ADOPTS WITHOUT AMENDMENTS:

International Energy Conservation Code 2021 (IECC 2021)

IECC—COMMERCIAL Provisions

IECC—RESIDENTIAL Provisions

Heads up: There are no amended sections in this chapter.

User note:

About this chapter: Chapter 4 presents the paths and options for compliance with the energy efficiency provisions. Chapter 4 contains energy efficiency provisions for the building envelope, mechanical and water heating systems, lighting and additional efficiency requirements. A performance alternative, energy rating alternative, and tropical regional alternative are also provided to allow for energy code compliance other than by the prescriptive method.

This chapter applies to residential buildings.

Residential buildings shall comply with Section R401.2.5 and either Sections R401.2.1, R401.2.2, R401.2.3 or R401.2.4

Exception: Additions, alterations, repairs and changes of occupancy to existing buildings complying with Chapter 5.

The Prescriptive Compliance Option requires compliance with Sections R401 through R404.
The Total Building Performance Option requires compliance with Section R405.
The Energy Rating Index (ERI) Option requires compliance with Section R406.
The Tropical Climate Region Option requires compliance with Section R407.
This section establishes additional requirements applicable to all compliance approaches to achieve additional energy efficiency.
  1. For buildings complying with Section R401.2.1, one of the additional efficiency package options shall be installed according to Section R408.2.
  2. For buildings complying with Section R401.2.2 , the building shall meet one of the following:

    2.1.  One of the additional efficiency package options in Section R408.2 shall be installed without including such measures in the proposed design under Section R405; or

    2.2.  The proposed design of the building under Section R405.3 shall have an annual energy cost that is less than or equal to 95 percent of the annual energy cost of the standard reference design.

  3. For buildings complying with the Energy Rating Index alternative Section R401.2.3, the Energy Rating Index value shall be at least 5 percent less than the Energy Rating Index target specified in Table R406.5.
The option selected for compliance shall be identified in the certificate required by Section R401.3.

A permanent certificate shall be completed by the builder or other approved party and posted on a wall in the space where the furnace is located, a utility room or an approved location inside the building. Where located on an electrical panel, the certificate shall not cover or obstruct the visibility of the circuit directory label, service disconnect label or other required labels. The certificate shall indicate the following:

  1. The predominant R-values of insulation installed in or on ceilings, roofs, walls, foundation components such as slabs, basement walls, crawl space walls and floors and ducts outside conditioned spaces.
  2. U-factors of fenestration and the solar heat gain coefficient (SHGC) of fenestration. Where there is more than one value for any component of the building envelope, the certificate shall indicate both the value covering the largest area and the area weighted average value if available.
  3. The results from any required duct system and building envelope air leakage testing performed on the building.
  4. The types, sizes and efficiencies of heating, cooling and service water-heating equipment. Where a gas-fired unvented room heater, electric furnace or baseboard electric heater is installed in the residence, the certificate shall indicate "gas-fired unvented room heater," "electric furnace" or "baseboard electric heater," as appropriate. An efficiency shall not be indicated for gas-fired unvented room heaters, electric furnaces and electric baseboard heaters.
  5. Where on-site photovoltaic panel systems have been installed, the array capacity, inverter efficiency, panel tilt and orientation shall be noted on the certificate.
  6. For buildings where an Energy Rating Index score is determined in accordance with Section R406, the Energy Rating Index score, both with and without any on-site generation, shall be listed on the certificate.
  7. The code edition under which the structure was permitted and the compliance path used.

The building thermal envelope shall comply with the requirements of Sections R402.1.1 through R402.1.5.

Exceptions:

  1. The following low-energy buildings, or portions thereof, separated from the remainder of the building by building thermal envelope assemblies complying with this section shall be exempt from the building thermal envelope provisions of Section R402.

    1.1.  Those with a peak design rate of energy usage less than 3.4 Btu/h × ft2 (10.7 W/m2) or 1.0 watt/ft2 of floor area for space-conditioning purposes.

    1.2.  Those that do not contain conditioned space.

  2. Log homes designed in accordance with ICC 400.
Wall assemblies in the building thermal envelope shall comply with the vapor retarder requirements of Section R702.7 of the International Residential Code or Section 1404.3 of the International Building Code, as applicable.
The building thermal envelope shall meet the requirements of Table R402.1.2, based on the climate zone specified in Chapter 3. Assemblies shall have a U-factor equal to or less than that specified in Table R402.1.2. Fenestration shall have a U-factor and glazed fenestration SHGC equal to or less than that specified in Table R402.1.2.

TABLE R402.1.2

MAXIMUM ASSEMBLY U-FACTORSAND FENESTRATION REQUIREMENTS

CLIMATE ZONE FENESTRATION U-FACTORf SKYLIGHT U-FACTOR GLAZED FENESTRATION SHGCd, e CEILING U-FACTOR WOOD FRAME WALL U-FACTOR MASS WALL U-FACTORb FLOOR U-FACTOR BASEMENT WALL U-FACTOR CRAWL SPACE WALL U-FACTOR
0 0.50 0.75 0.25 0.035 0.084 0.197 0.064 0.360 0.477
1 0.50 0.75 0.25 0.035 0.084 0.197 0.064 0.360 0.477
2 0.40 0.65 0.25 0.026 0.084 0.165 0.064 0.360 0.477
3 0.30 0.55 0.25 0.026 0.060 0.098 0.047 0.091c 0.136
4 except Marine 0.30 0.55 0.40 0.024 0.045 0.098 0.047 0.059 0.065
5 and Marine 4 0.30 0.55 0.40 0.024 0.045 0.082 0.033 0.050 0.055
6 0.30 0.55 NR 0.024 0.045 0.060 0.033 0.050 0.055
7 and 8 0.30 0.55 NR 0.024 0.045 0.057 0.028 0.050 0.055

For SI: 1 foot = 304.8 mm.

  1. Nonfenestration U-factors shall be obtained from measurement, calculation or an approved source.
  2. Mass walls shall be in accordance with Section R402.2.5. Where more than half the insulation is on the interior, the mass wall U-factors shall not exceed 0.17 in Climate Zones 0 and 1, 0.14 in Climate Zone 2, 0.12 in Climate Zone 3, 0.087 in Climate Zone 4 except Marine, 0.065 in Climate Zone 5 and Marine 4, and 0.057 in Climate Zones 6 through 8.
  3. In Warm Humid locations as defined by Figure R301.1 and Table R301.1, the basement wall U-factor shall not exceed 0.360.
  4. The SHGC column applies to all glazed fenestration.

    Exception: In Climate Zones 0 through 3, skylights shall be permitted to be excluded from glazed fenestration SHGC requirements provided that the SHGC for such skylights does not exceed 0.30.

  5. There are no SHGC requirements in the Marine Zone.
  6. A maximum U-factor of 0.32 shall apply in Marine Climate Zone 4 and Climate Zones 5 through 8 to vertical fenestration products installed in buildings located either:

    1. Above 4,000 feet in elevation above sea level, or
    2. In windborne debris regions where protection of openings is required by Section R301.2.1.2 of the International Residential Code.
Assemblies with R-value of insulation materials equal to or greater than that specified in Table R402.1.3 shall be an alternative to the U-factor in Table R402.1.2

TABLE R402.1.3

INSULATION MINIMUM R-VALUES AND FENESTRATION REQUIREMENTS BY COMPONENTa

CLIMATE ZONE FENESTRATION U-FACTORb, i SKYLIGHTb U-FACTOR GLAZED FENESTRATION SHGCb, e CEILING R-VALUE WOOD FRAME WALL R-VALUEg MASS WALL R-VALUEh FLOOR R-VALUE BASEMENTc,g WALL R-VALUE SLABd R-VALUE & DEPTH CRAWL SPACEc,g WALL R-VALUE
0 NR 0.75 0.25 30 13 or 0 & 10ci 3/4 13 0 0 0
1 NR 0.75 0.25 30 13 or 0 & 10ci 3/4 13 0 0 0
2 0.40 0.65 0.25 49 13 or 0 & 10ci 4/6 13 0 0 0
3 .30 0.55 0.25 49 20 or 13 & 5cih
or 0 & 15cih
8/13 19 5ci or 13f 10ci, 2 ft 5ci or 13f
4 except Marine .30 0.55 0.40 60 30 or 20 & 5cih or 13 & 10cih or 0 & 20cih 8/13 19 10ci or 13 10ci, 4 ft 10ci or 13
5 and Marine 4 0.30i 0.55 0.40 60 30 or 20 & 5cih or 13 & 10cih or 0 & 20cih 13/17 30 15ci or 19 or
13 & 5ci
10ci, 4 ft 15ci or 19 or 13 & 5ci
6 0.30i 0.55 NR 60 30 or 20 & 5cih or 13 & 10cih or 0 & 20cih 15/20 30 15ci or 19 or
13 & 5ci
10ci, 4 ft 15ci or 19 or 13 & 5ci
7 and 8 0.30i 0.55 NR 60 30 or 20 & 5cih or 13 & 10cih or 0 & 20cih 19/21 38 15ci or 19 or
13 & 5ci
10ci, 4 ft 15ci or 19 or 13 & 5ci

For SI: 1 foot = 304.8 mm.

NR = Not Required.

ci = continuous insulation.

  1. R-values are minimums. U-factors and SHGC are maximums. Where insulation is installed in a cavity that is less than the label or design thickness of the insulation, the installed R-value of the insulation shall be not less than the R-value specified in the table.
  2. The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration.

    Exception: In Climate Zones 0 through 3, skylights shall be permitted to be excluded from glazed fenestration SHGC requirements provided that the SHGC for such skylights does not exceed 0.30.

  3. "5ci or 13" means R-5 continuous insulation (ci) on the interior or exterior surface of the wall or R-13 cavity insulation on the interior side of the wall. "10ci or 13" means R-10 continuous insulation (ci) on the interior or exterior surface of the wall or R-13 cavity insulation on the interior side of the wall. "15ci or 19 or 13 + 5ci" means R-15 continuous insulation (ci) on the interior or exterior surface of the wall; or R-19 cavity insulation on the interior side of the wall; or R-13 cavity insulation on the interior of the wall in addition to R-5 continuous insulation on the interior or exterior surface of the wall.
  4. R-5 insulation shall be provided under the full slab area of a heated slab in addition to the required slab-edge insulation R-value for slabs. as indicated in the table. The slab edge insulation for heated slabs shall not be required to extend below the slab.
  5. There are no SHGC requirements in the Marine Zone.
  6. Basement wall insulation is not required in Warm Humid locations as defined by Figure R301.1 and Table R301.1.
  7. The first value is cavity insulation; the second value is continuous insulation. Therefore, as an example, "13 + 5" means R-13 cavity insulation plus R-5 continuous insulation.
  8. Mass walls shall be in accordance with Section R402.2.5. The second R-value applies where more than half of the insulation is on the interior of the mass wall.
  9. A maximum U-factor of 0.32 shall apply in Climate Zones 3 through 8 to vertical fenestration products installed in buildings located either:

    1. Above 4,000 feet in elevation, or
    2. In windborne debris regions where protection of openings is required by Section R301.2.1.2 of the International Residential Code.
Cavity insulation alone shall be used to determine compliance with the cavity insulation R-value requirements in Table R402.1.3. Where cavity insulation is installed in multiple layers, the R-values of the cavity insulation layers shall be summed to  determine compliance with the cavity insulation R-value requirements. The manufacturer's settled R-value shall be used for blown-in insulation. Continuous insulation (ci) alone shall be used to determine compliance with the continuous insulation R-value requirements in Table R402.1.3. Where continuous insulation is installed in multiple layers, the R-values of the continuous insulation layers shall be summed to determine compliance with the continuous insulation R-value requirements. Cavity insulation R-values shall not be used to determine compliance with the continuous insulation R-value requirements in Table R402.1.3. Computed R-values shall not include an R-value for other building materials or air films. Where insulated siding is used for the purpose of complying with the continuous insulation requirements of Table R402.1.3, the manufacturer's labeled R-value for the insulated siding shall be reduced by R-0.6.
Where the total building thermal envelope UA, the sum of U-factor times assembly area, is less than or equal to the total UA resulting from multiplying the U-factors in Table R402.1.2 by the same assembly area as in the proposed building, the building shall be considered to be in compliance with Table R402.1.2. The UA calculation shall be performed using a method consistent with the ASHRAE Handbook of Fundamentals and shall include the thermal bridging effects of framing materials. In addition to UA compliance, the SHGC requirements of Table R402.1.2 and the maximum fenestration U-factors of Section R402.5 shall be met.
In addition to the requirements of Section R402.1, insulation shall meet the specific requirements of Sections R402.2.1 through R402.2.12.
Where Section R402.1.3 requires R-49 insulation in the ceiling or attic, installing R-38 over 100 percent of the ceiling or attic area requiring insulation shall satisfy the requirement for R-49 insulation wherever the full height of uncompressed R-38 insulation extends over the wall top plate at the eaves. Where Section R402.1.3 requires R-60 insulation in the ceiling or attic, installing R-49 over 100 percent of the ceiling or attic area requiring insulation shall satisfy the requirement for R-60 insulation wherever the full height of uncompressed R-49 insulation extends over the wall top plate at the eaves. This reduction shall not apply to the insulation and fenestration criteria in Section R402.1.2 and the Total UA alternative in Section R402.1.5.
Where Section R402.1.3 requires insulation R-values greater than R-30 in the interstitial space above a ceiling and below the structural roof deck, and the design of the roof/ceiling assembly does not allow sufficient space for the required insulation, the minimum required insulation R-value for such roof/ceiling assemblies shall be R-30. Insulation shall extend over the top of the wall plate to the outer edge of such plate and shall not be compressed. This reduction of insulation from the requirements of Section R402.1.3 shall be limited to 500 square feet (46 m2) or 20 percent of the total insulated ceiling area, whichever is less. This reduction shall not apply to the Total UA alternative in Section R402.1.5.
For air-permeable insulation in vented attics, a baffle shall be installed adjacent to soffit and eave vents. Baffles shall maintain a net free area opening equal to or greater than the size of the vent. The baffle shall extend over the top of the attic insulation. The baffle shall be permitted to be any solid material. The baffle shall be installed to the outer edge of the exterior wall top plate so as to provide maximum space for attic insulation coverage over the top plate. Where soffit venting is not continuous, baffles shall be installed continuously to prevent ventilation air in the eave soffit from bypassing the baffle.
Access hatches and doors from conditioned to unconditioned spaces such as attics and crawl spaces shall be insulated to the same R-value required by Table R402.1.3 for the wall or ceiling in which they are installed.

Exceptions:

  1. Vertical doors providing access from conditioned spaces to unconditioned spaces that comply with the fenestration requirements of Table R402.1.3 based on the applicable climate zone specified in Chapter 3.
  2. Horizontal pull-down, stair-type access hatches in ceiling assemblies that provide access from conditioned to unconditioned spaces in Climate Zones 0 through 4 shall not be required to comply with the insulation level of the surrounding surfaces provided the hatch meets all of the following:

    2.1.  The average U-factor of the hatch shall  be less than or equal to U-0.10 or have an average insulation R-value of R-10 or greater.

    2.2.  Not less than 75 percent of the panel area shall have an insulation R-value of R-13 or greater.

    2.3.  The net area of the framed opening shall be less than or equal to 13.5 square feet (1.25 m2).

    2.4.  The perimeter of the hatch edge shall be weatherstripped.

The reduction shall not apply to the total UA alternative in Section R402.1.5.
Vertical or horizontal access hatches and doors from conditioned spaces to unconditioned spaces such as attics and crawl spaces shall be weatherstripped. Access that prevents damaging or compressing the insulation shall be provided to all equipment. Where loose-fill insulation is installed, a wood-framed or equivalent baffle, retainer, or dam shall be installed to prevent loose-fill insulation from spilling into living space, from higher to lower sections of the attic and from attics covering conditioned spaces to unconditioned spaces. The baffle or retainer shall provide a permanent means of maintaining the installed R-value of the loose-fill insulation.

Mass walls where used as a component of the building thermal envelope shall be one of the following:

  1. Above-ground walls of concrete block, concrete, insulated concrete form, masonry cavity, brick but not brick veneer, adobe, compressed earth block, rammed earth, solid timber, mass timber or solid logs.
  2. Any wall having a heat capacity greater than or equal to 6 Btu/ft2× °F (123 kJ/m2× K).
Steel-frame ceilings, walls, and floors shall comply with the insulation requirements of Table R402.2.6 or the U-factor requirements of Table R402.1.2. The calculation of the U-factor for a steel-frame envelope assembly shall use a series-parallel path calculation method.

TABLE R402.2.6

STEEL-FRAME CEILING, WALL AND FLOOR INSULATION R-VALUES

WOOD FRAME R-VALUE REQUIREMENT COLD-FORMED STEEL-FRAME EQUIVALENT R-VALUEa
Steel Truss Ceilingsb

R-30

R-38 or R-30 + 3 or R-26 + 5

R-38

R-49 or R-38 + 3

R-49

R-38 + 5
Steel Joist Ceilingsb

R-30

R-38 in 2 × 4 or 2 × 6 or 2 × 8 R-49 in any framing

R-38

R-49 in 2 × 4 or 2 × 6 or 2 × 8 or 2 × 10
Steel-frame Wall, 16 inches on center

R-13

R-13 + 4.2 or R-21 + 2.8 or R-0 + 9.3 or R-15 + 3.8 or R-21 + 3.1

R-13+5

R-0 + 15 or R-13 + 9 or R-15 + 8.5 or R-19 + 8 or R-21 + 7

R-13+10

R-0+20 or R-13 + 15 or R-15 + 14 or R-19 + 13 or R-21 + 13

R-20

R-0 + 14.0 or R-13 + 8.9 or R-15 + 8.5 or R-19 + 7.8 or R-21 + 7.5

R-20 + 5

R-13 + 12.7 or R-15 + 12.3 or R-19 + 11.6 or R-21 + 11.3 or R-25 + 10.9

R-21

R-0 + 14.6 or R-13 + 9.5 or R-15 + 9.1 or R-19 + 8.4 or R-21 + 8.1 or R-25 + 7.7
Steel-frame Wall, 24 inches on center

R-13

R-0 + 9.3 or R-13 + 3.0 or R-15 + 2.4

R-13+5

R-0 + 15 or R-13 + 7.5 or R-15 + 7 or R-19 + 6 or R-21 + 6

R-13+10

R-0 + 20 or R-13 + 13 or R-15 + 12 or R-19 + 11 or R-21 + 11

R-20

R-0 + 14.0 or R-13 + 7.7 or R-15 + 7.1 or R-19 + 6.3 or R-21 + 5.9

R-20+5

R-13 + 11.5 or R-15 + 10.9 or R-19 + 10.1 or R-21 + 9.7 or R-25 + 9.1

R-21

R-0 + 14.6 or R-13 + 8.3 or R-15 + 7.7 or R-19 + 6.9 or R-21 + 6.5 or R-25 + 5.9
Steel Joist Floor

R-13

R-19 in 2 × 6, or R-19 + 6 in 2 × 8 or 2 × 10

R-19

R-19 + 6 in 2 × 6, or R-19 + 12 in 2 × 8 or 2 × 10
  1. The first value is cavity insulation R-value; the second value is continuous insulation R-value. Therefore, for example, "R-30 + 3" means R-30 cavity insulation plus R-3 continuous insulation.
  2. Insulation exceeding the height of the framing shall cover the framing.

Floor cavity insulation shall comply with one of the following:

  1. Installation shall be installed to maintain permanent contact with the underside of the subfloor decking in accordance with manufacturer instructions to maintain required R-value or readily fill the available cavity space.
  2. Floor framing cavity insulation shall be permitted to be in contact with the top side of sheathing separating the cavity and the unconditioned space below. Insulation shall extend from the bottom to the top of all perimeter floor framing members and the framing members shall be air sealed.
  3. A combination of cavity and continuous insulation shall be installed so that the cavity insulation is in contact with the top side of the continuous insulation that is installed on the underside of the floor framing separating the cavity and the unconditioned space below. The combined R-value of the cavity and continuous insulation shall equal the required R-value for floors. Insulation shall extend from the bottom to the top of all perimeter floor framing members and the framing members shall be air sealed.
Basement walls shall be insulated in accordance with Table R402.1.3.

Exception: Basement walls associated with unconditioned basements where all of the following requirements are met:

  1. The floor overhead, including the underside stairway stringer leading to the basement, is insulated in accordance with Section R402.1.3  and applicable provisions of Sections R402.2 and R402.2.7.
  2. There are no uninsulated duct, domestic hot water, or hydronic heating surfaces exposed to the basement.
  3. There are no HVAC supply or return diffusers serving the basement.
  4. The walls surrounding the stairway and adjacent to conditioned space are insulated in accordance with Section R402.1.3 and applicable provisions of Section R402.2.
  5. The door(s) leading to the basement from conditioned spaces are insulated in accordance with Sections R402.1.3 and applicable provisions of Section R402.2, and weatherstripped in accordance with Section R402.4.
  6. The building thermal envelope separating the basement from adjacent conditioned spaces complies with Section R402.4.
Where basement walls are insulated, the insulation shall be installed from the top of the basement wall down to 10 feet (3048 mm) below grade or to the basement floor, whichever is less.

Slab-on-grade floors with a floor surface less than 12 inches (305 mm) below grade shall be insulated in accordance with Table R402.1.3.

Exception: Slab-edge insulation is not required in jurisdictions designated by the code official as having a very heavy termite infestation.

Where installed, the insulation shall extend downward from the top of the slab on the outside or inside of the foundation wall. Insulation located below grade shall be extended the distance provided in Table R402.1.3 or the distance of the proposed design, as applicable, by any combination of vertical insulation, insulation extending under the slab or insulation extending out from the building. Insulation extending away from the building shall be protected by pavement or by not less than 10 inches (254 mm) of soil. The top edge of the insulation installed between the exterior wall and the edge of the interior slab shall be permitted to be cut at a 45-degree (0.79 rad) angle away from the exterior wall.
Crawl space walls shall be insulated in accordance with Table R402.1.3.

Exception: Crawl space walls associated with a crawl space that is vented to the outdoors and the floor overhead is insulated in accordance with Table R402.1.3 and Section R402.2.7.

Where crawl space wall insulation is installed, it shall be permanently fastened to the wall and shall extend downward from the floor to the finished grade elevation and then vertically or horizontally for not less than an additional 24 inches (610 mm). Exposed earth in unvented crawl space foundations shall be covered with a continuous Class I vapor retarder in accordance with the International Building Code or International Residential Code, as applicable. Joints of the vapor retarder shall overlap by 6 inches (153 mm) and be sealed or taped. The edges of the vapor retarder shall extend not less than 6 inches (153 mm) up stem walls and shall be attached to the stem walls.
Insulation shall not be required on the horizontal portion of a foundation that supports a masonry veneer.

Sunrooms enclosing conditioned space and heated garages shall meet the insulation requirements of this code.

Exception: For sunrooms and heated garages provided thermal isolation, and enclosed conditioned space, the following exceptions to the insulation requirements of this code shall apply:

  1. The minimum ceiling insulation R-values shall be R-19 in Climate Zones  0 through 4 and R-24 in Climate Zones 5 through 8.
  2. The minimum wall insulation R-value shall be R-13 in all climate zones. Walls separating a sunroom or heated garage with thermal isolation from conditioned space shall comply with the building thermal envelope requirements of this code.
In addition to the requirements of Section R402, fenestration shall comply with Sections R402.3.1 through R402.3.5.
An area-weighted average of fenestration products shall be permitted to satisfy the U-factor requirements.

An area-weighted average of fenestration products more than 50-percent glazed shall be permitted to satisfy the SHGC requirements.

Dynamic glazing shall be permitted to satisfy the SHGC requirements of Table R402.1.2 provided that the ratio of the higher to lower labeled SHGC is greater than or equal to 2.4, and the dynamic glazing is automatically controlled to modulate the amount of solar gain into the space in multiple steps. Dynamic glazing shall be considered separately from other fenestration, and area-weighted averaging with other fenestration that is not dynamic glazing shall be prohibited.

Exception: Dynamic glazing shall not be required to comply with this section where both the lower and higher labeled SHGC comply with the requirements of Table R402.1.2.

Not greater than 15 square feet (1.4 m2) of glazed fenestration per dwelling unit shall be exempt from the U-factor and SHGC requirements in Section R402.1.2. This exemption shall not apply to the Total UA alternative in Section R402.1.5.
One side-hinged opaque door assembly not greater than 24 square feet (2.22 m2) in area shall be exempt from the U-factor requirement in Section R402.1.2. This exemption shall not apply to the Total UA alternative in Section R402.1.5.

Sunrooms and heated garages enclosing conditioned space shall comply with the fenestration requirements of this code.

Exception: In Climate Zones 2 through 8, for sunrooms and heated garages with thermal isolation and enclosing conditioned space, the fenestration U-factor shall not exceed 0.45 and the skylight U-factor shall not exceed 0.70.

New fenestration separating a sunroom or heated garage with thermal isolation from conditioned space shall comply with the building thermal envelope requirements of this code.

The building thermal envelope shall be constructed to limit air leakage in accordance with the requirements of Sections R402.4.1 through R402.4.5.
The building thermal envelope shall comply with Sections R402.4.1.1 through R402.4.1.3. The sealing methods between dissimilar materials shall allow for differential expansion and contraction.
The components of the building thermal envelope as indicated in Table R402.4.1.1 shall be installed in accordance with the manufacturer's instructions and the criteria indicated in Table R402.4.1.1, as applicable to the method of construction. Where required by the code officialan approved third party shall inspect all components and verify compliance.

TABLE R402.4.1.1

AIR BARRIER, AIR SEALING AND INSULATION INSTALLATIONa

COMPONENT AIR BARRIER CRITERIA INSULATION INSTALLATION CRITERIA
General requirements A continuous air barrier shall be installed in the building envelope.

Breaks or joints in the air barrier shall be sealed.
Air-permeable insulation shall not be used as a sealing material.
Ceiling/attic The air barrier in any dropped ceiling or soffit shall be aligned with the insulation and any gaps in the air barrier shall be sealed.

Access openings, drop down stairs or knee wall doors to unconditioned attic spaces shall be sealed.
The insulation in any dropped ceiling/soffit shall be aligned with the air barrier.
Walls The junction of the foundation and sill plate shall be sealed.

The junction of the top plate and the top of exterior walls shall be sealed.

Knee walls shall be sealed.
Cavities within corners and headers of frame walls shall be insulated by completely filling the cavity with a material having a thermal resistance, R-value, of not less than R-3 per inch. Exterior thermal envelope insulation for framed walls shall be installed in substantial contact and continuous alignment with the air barrier.
Windows, skylights and doors The space between framing and skylights, and the jambs of windows and doors, shall be sealed.
Rim joists Rim joists shall include an exterior air barrier.b

The junctions of the rim board to the sill plate and the rim board and the subfloor shall be air sealed.
Rim joists shall be insulated so that the insulation maintains permanent contact with the exterior rim board.b
Floors, including cantilevered floors and floors above garages The air barrier shall be installed at any exposed edge of insulation. Floor framing cavity insulation shall be installed to maintain permanent contact with the underside of subfloor decking. Alternatively, floor framing cavity insulation shall be in contact with the top side of sheathing, or continuous insulation installed on the underside of floor framing and extending from the bottom to the top of all perimeter floor framing members.
Basement crawl space and slab foundations Exposed earth in unvented crawl spaces shall be covered with a Class I vapor retarder/air barrier in accordance with Section R402.2.10 .

Penetrations through concrete foundation walls and slabs shall be air sealed.

Class 1 vapor retarders shall not be used as an air barrier on below-grade walls and shall be installed in accordance with Section R702.7 of the International Residential Code.
Crawl space insulation, where provided instead of floor insulation, shall be installed in accordance with Section R402.2.10.

Conditioned basement foundation wall insulation shall be installed in accordance with Section R402.2.8.1.

Slab-on-grade floor insulation shall be installed in accordance with Section R402.2.10.
Shafts, penetrations Duct and flue shafts to exterior or unconditioned space shall be sealed.

Utility penetrations of the air barrier shall be caulked, gasketed or otherwise sealed and shall allow for expansion, contraction of materials and mechanical vibration.
Insulation shall be fitted tightly around utilities passing through shafts and penetrations in the building thermal envelope to maintain required R-value.
Narrow cavities

Narrow cavities of 1 inch or less that are not able to be insulated shall be air sealed.

Batts to be installed in narrow cavities shall be cut to fit or narrow cavities shall be filled with insulation that on installation readily conforms to the available cavity space.
Garage separation Air sealing shall be provided between the garage and conditioned spaces. Insulated portions of the garage separation assembly shall be installed in accordance with Sections R303 and R402.2.7.
Recessed lighting

Recessed light fixtures installed in the building thermal envelope shall be air sealed in accordance with Section R402.4.5 

Recessed light fixtures installed in the building thermal envelope shall be airtight and IC rated, and shall be buried or surrounded with insulation.
Plumbing, wiring or other obstructions

All holes created by wiring, plumbing or other obstructions in the air barrier assembly shall be air sealed.

Insulation shall be installed to fill the available space and surround wiring, plumbing, or other obstructions, unless the required R-value can be met by installing insulation and air barrier systems completely to the exterior side of the obstructions.
Shower/tub on exterior wall The air barrier installed at exterior walls adjacent to showers and tubs shall separate the wall from the shower or tub. Exterior walls adjacent to showers and tubs shall be insulated.
Electrical/phone box on exterior walls The air barrier shall be installed behind electrical and communication boxes. Alternatively, air-sealed boxes shall be installed.
HVAC register boots HVAC supply and return register boots that penetrate building thermal envelope shall be sealed to the subfloor, wall covering or ceiling penetrated by the boot.
Concealed sprinklers Where required to be sealed, concealed fire sprinklers shall only be sealed in a manner that is recommended by the manufacturer. Caulking or other adhesive sealants shall not be used to fill voids between fire sprinkler cover plates and walls or ceilings.
  1. Inspection of log walls shall be in accordance with the provisions of ICC 400.
  2. Air barrier and insulation full enclosure is not required in unconditioned/ventilated attic spaces and at rim joists.

The building or dwelling unit shall be tested for air leakage. The maximum air leakage rate for any building or dwelling unit under any compliance path shall not exceed 5.0 air changes per hour or 0.28 cubic feet per minute (CFM) per square foot [0.0079 m3/(s × m2)] of dwelling unit enclosure area. Testing shall be conducted in accordance with ANSI/RESNET/ICC 380, ASTM E779 or ASTM E1827 and reported at a pressure of 0.2 inch w.g. (50 Pascals). Where required by the code official, testing shall be conducted by an approved third party. A written report of the results of the test shall be signed by the party conducting the test and provided to the code official. Testing shall be performed at any time after creation of all penetrations of the building thermal envelope have been sealed.

Exception: For heated, attached private garages and heated, detached private garages accessory to one- and two-family dwellings and townhouses not more than three stories above grade plane in height, building envelope tightness and insulation installation shall be considered acceptable where the items in Table R402.4.1.1, applicable to the method of construction, are field verified. Where required by the code official, an approved third party independent from the installer shall inspect both air barrier and insulation installation criteria. Heated, attached private garage space and heated, detached private garage space shall be thermally isolated from all other habitable, conditioned spaces in accordance with Sections R402.2.12 and R402.3.5, as applicable.

During testing:

  1. Exterior windows and doors, fireplace and stove doors shall be closed, but not sealed, beyond the intended weatherstripping or other infiltration control measures.
  2. Dampers including exhaust, intake, makeup air, backdraft and flue dampers shall be closed, but not sealed beyond intended infiltration control measures.
  3. Interior doors, where installed at the time of the test, shall be open.
  4. Exterior or interior terminations for continuous ventilation systems shall be sealed.
  5. Heating and cooling systems, where installed at the time of the test, shall be turned off.
  6. Supply and return registers, where installed at the time of the test, shall be fully open.

Exception: When testing individual dwelling units, an air leakage rate not exceeding 0.30 cubic feet per minute per square foot [0.008 m3/(s × m2)] of the dwelling unit enclosure area, tested in accordance with  ANSI/RESNET/ICC 380, ASTM E779 or ASTM E1827 and reported at a pressure of 0.2 inch w.g. (50 Pa), shall be permitted in all climate zones for:

  1. Attached single and multiple-family building dwelling units.
  2. Buildings or dwelling units that are 1,500 square feet (139.4 m2) or smaller.
Mechanical ventilation shall be provided in accordance with Section M1505 of the International Residential Code or Section 403.3.2 of the International Mechanical Code, as applicable, or with other approved means of ventilation.
When complying with Section R401.2.1, the building or dwelling unit shall have an air leakage rate not exceeding 5.0 air changes per hour in Climate Zones 0, 1 and 2, and 3.0 air changes per hour in Climate Zones 3 through 8, when tested in accordance with Section R402.4.1.2.
New wood-burning fireplaces shall have tight-fitting flue dampers or doors, and outdoor combustion air. Where using tight-fitting doors on factory-built fireplaces listed and labeled in accordance with UL 127, the doors shall be tested and listed for the fireplace.

Windows, skylights and sliding glass doors shall have an air infiltration rate of not greater than 0.3 cfm per square foot (1.5 L/s/m2), and for swinging doors, not greater than 0.5 cfm per square foot (2.6 L/s/m2), when tested in accordance with NFRC 400 or AAMA/WDMA/CSA 101/I.S.2/A440 by an accredited, independent laboratory and listed and labeled by the manufacturer.

Exception: Site-built windows, skylights and doors.

In Climate Zones 3 through 8, where open combustion air ducts provide combustion air to open combustion fuel-burning appliances, the appliances and combustion air opening shall be located outside the building thermal envelope or enclosed in a room that is isolated from inside the thermal envelope. Such rooms shall be sealed and insulated in accordance with the envelope requirements of Table R402.1.3, where the walls, floors and ceilings shall meet a minimum of the basement wall R-value requirement. The door into the room shall be fully gasketed and any water lines and ducts in the room insulated in accordance with Section R403. The combustion air duct shall be insulated where it passes through conditioned space to an R-value of not less than R-8.

Exceptions:

  1. Direct vent appliances with both intake and exhaust pipes installed continuous to the outside.
  2. Fireplaces and stoves complying with Section R402.4.2 and Section R1006 of the International Residential Code.
Recessed luminaires installed in the building thermal envelope shall be sealed to limit air leakage between conditioned and unconditioned spaces. Recessed luminaires shall be IC-rated and labeled as having an air leakage rate of not greater than 2.0 cfm (0.944 L/s) when tested in accordance with ASTM E283 at a pressure differential of 1.57 psf (75 Pa). Recessed luminaires shall be sealed with a gasket or caulked between the housing and the interior wall or ceiling covering.
Electrical and communication outlet boxes installed in the building thermal envelope shall be sealed to limit air leakage between conditioned and unconditioned spaces. Electrical and communication outlet boxes shall be tested in accordance with NEMA OS 4, Requirements for Air-Sealed Boxes for Electrical and Communication Applications, and shall have an air leakage rate of not greater than 2.0 cubic feet per minute (0.944 L/s) at a pressure differential of 1.57 psf (75 Pa).  Electrical and communication outlet boxes shall be marked "NEMA OS 4" or "OS 4" in accordance with NEMA OS 4. Electrical and communication outlet boxes shall be installed per the manufacturer's instructions and with any supplied components required to achieve compliance with NEMA OS 4.

The area-weighted average maximum fenestration U-factor permitted using tradeoffs from Section R402.1.5 or R405 shall be 0.48 in Climate Zones 4 and 5 and 0.40 in Climate Zones 6 through 8 for vertical fenestration, and 0.75 in Climate Zones 4 through 8 for skylights. The area-weighted average maximum fenestration SHGC permitted using tradeoffs from Section R405 in Climate Zones  0 through 3 shall be 0.40.

Exception: The maximum U-factor and solar heat gain coefficient (SHGC) for fenestration shall not be required in storm shelters complying with ICC 500.

Not less than one thermostat shall be provided for each separate heating and cooling system.
The thermostat controlling the primary heating or cooling system of the dwelling unit shall be capable of controlling the heating and cooling system on a daily schedule to maintain different temperature set points at different times of day and different days of the week. This thermostat shall include the capability to set back or temporarily operate the system to maintain zone temperatures of not less than 55°F (13°C) to not greater than 85°F (29°C). The thermostat shall be programmed initially by the manufacturer with a heating temperature setpoint of not greater than 70°F (21°C) and a cooling temperature setpoint of not less than 78°F (26°C).
Heat pumps having supplementary electric-resistance heat shall have controls that, except during defrost, prevent supplemental heat operation when the heat pump compressor can meet the heating load.
The manufacturer shall equip each gas, oil and electric boiler (other than a boiler equipped with a tankless domestic water heating coil) with automatic means of adjusting the water temperature supplied by the boiler to ensure incremental change of the inferred heat load will cause an incremental change in the temperature of the water supplied by the boiler. This can be accomplished with outdoor reset, indoor reset or water temperature sensing.
Ducts and air handlers shall be installed in accordance with Sections R403.3.1 through R403.3.7.
Supply and return ducts located outside conditioned space shall be insulated to an R-value of not less than R-8 for ducts 3 inches (76 mm) in diameter and larger and not less than R-6 for ducts smaller than 3 inches (76 mm) in diameter. Ducts buried beneath a building shall be insulated as required per this section or have an equivalent thermal distribution efficiency. Underground ducts utilizing the thermal distribution efficiency method shall be listed and labeled to indicate the R-value equivalency.

For ductwork to be considered inside a conditioned space, it shall comply with one of the following:

  1. The duct system shall be located completely within the continuous air barrier and within the building thermal envelope.
  2. Ductwork in ventilated attic spaces shall be buried within ceiling insulation in accordance with Section R403.3.3 and all of the following conditions shall exist:

    2.1.  The air handler is located completely within the continuous air barrier and within the building thermal envelope.

    2.2.  The duct leakage, as measured either by a rough-in test of the ducts or a post-construction total system leakage test to outside the building thermal envelope in accordance with Section R403.3.6, is less than or equal to 1.5 cubic feet per minute (42.5 L/min) per 100 square feet (9.29 m2) of conditioned floor area served by the duct system.

    2.3.  The ceiling insulation R-value installed against and above the insulated duct is greater than or equal to the proposed ceiling insulation R-value, less the R-value of the insulation on the duct.

  3. Ductwork in floor cavities located over unconditioned space shall comply with all of the following:

    3.1.  A continuous air barrier installed between unconditioned space and the duct.

    3.2.  Insulation installed in accordance with Section R402.2.7.

    3.3.  A minimum R-19 insulation installed in the cavity width separating the duct from unconditioned space.

  4. Ductwork located within exterior walls of the building thermal envelope shall comply with the following:

    4.1.  A continuous air barrier installed between unconditioned space and the duct.

    4.2.  Minimum R-10 insulation installed in the cavity width separating the duct from the outside sheathing.

    4.3.  The remainder of the cavity insulation shall be fully insulated to the drywall side.

Where supply and return air ducts are partially or completely buried in ceiling insulation, such ducts shall comply with all of the following:

  1. The supply and return ducts shall have an insulation R-value not less than R-8.
  2. At all points along each duct, the sum of the ceiling insulation R-value against and above the top of the duct, and against and below the bottom of the duct, shall be not less than R-19, excluding the R-value of the duct insulation.
  3. In Climate Zones 0A, 1A, 2A and 3A, the supply ducts shall be completely buried within ceiling insulation, insulated to an R-value of not less than R-13 and in compliance with the vapor retarder requirements of Section 604.11 of the International Mechanical Code or Section M1601.4.6 of the International Residential Code, as applicable.

    Exception: Sections of the supply duct that are less than 3 feet (914 mm) from the supply outlet shall not be required to comply with these requirements.

Where using the Total Building Performance Compliance Option in accordance with Section R401.2.2, sections of ducts that are installed in accordance with Section R403.3.3, located directly on or within 5.5 inches (140 mm) of the ceiling, surrounded with blown-in attic insulation having an R-value of R-30 or greater and located such that the top of the duct is not less than 3.5 inches (89 mm) below the top of the insulation, shall be considered as having an effective duct insulation R-value of R-25.
Ducts, air handlers and filter boxes shall be sealed. Joints and seams shall comply with either the International Mechanical Code or International Residential Code, as applicable.
Air handlers shall have a manufacturer's designation for an air leakage of not greater than 2 percent of the design airflow rate when tested in accordance with ASHRAE 193.

Ducts shall be pressure tested in accordance with ANSI/RESNET/ICC 380 or ASTM E1554 to determine air leakage by one of the following methods:

  1. Rough-in test: Total leakage shall be measured with a pressure differential of 0.1 inch w.g. (25 Pa) across the system, including the manufacturer's air handler enclosure if installed at the time of the test. Registers shall be taped or otherwise sealed during the test.
  2. Postconstruction test: Total leakage shall be measured with a pressure differential of 0.1 inch w.g. (25 Pa) across the entire system, including the manufacturer's air handler enclosure. Registers shall be taped or otherwise sealed during the test.
Exception: A duct air-leakage test shall not be required for ducts serving  ventilation systems that are not integrated with ducts serving heating or cooling systems.

A written report of the results of the test shall be signed by the party conducting the test and provided to the code official.

The total leakage of the ducts, where measured in accordance with Section R403.3.5, shall be as follows:

  1. Rough-in test: The total leakage shall be less than or equal to 4.0 cubic feet per minute (113.3 L/min) per 100 square feet (9.29 m2) of conditioned floor area where the air handler is installed at the time of the test. Where the air handler is not installed at the time of the test, the total leakage shall be less than or equal to 3.0 cubic feet per minute (85 L/min) per 100 square feet (9.29 m2) of conditioned floor area.
  2. Postconstruction test: Total leakage shall be less than or equal to 4.0 cubic feet per minute (113.3 L/min) per 100 square feet (9.29 m2) of conditioned floor area.
  3. Test for ducts within thermal envelope: Where all ducts and air handlers are located entirely within the building thermal envelope, total leakage shall be less than or equal to 8.0 cubic feet per minute (226.6 L/min) per 100 square feet (9.29 m2) of conditioned floor area.
Building framing cavities shall not be used as ducts or plenums.
Mechanical system piping capable of carrying fluids greater than 105°F (41°C) or less than 55°F (13°C) shall be insulated to an R-value of not less than R-3.
Piping insulation exposed to weather shall be protected from damage, including that caused by sunlight, moisture, equipment maintenance and wind. The protection shall provide shielding from solar radiation that can cause degradation of the material. Adhesive tape shall be prohibited.
Energy conservation measures for service hot water systems shall be in accordance with Sections R403.5.1 through R403.5.3.
Heated water circulation systems shall be in accordance with Section R403.5.1.1. Heat trace temperature maintenance systems shall be in accordance with Section R403.5.1.2. Automatic controls, temperature sensors and pumps shall be in a location with access. Manual controls shall be in a location with ready access.
Heated water circulation systems shall be provided with a circulation pump. The system return pipe shall be a dedicated return pipe or a cold water supply pipe. Gravity and thermosyphon circulation systems shall be prohibited. Controls for circulating hot water system pumps shall automatically turn off the pump when the water in the circulation loop is at the desired temperature and when there is no demand for hot water. The controls shall limit the temperature of the water entering the cold water piping to not greater than 104°F (40°C).
Where installed, demand recirculation water systems shall have controls that start the pump upon receiving a signal from the action of a user of a fixture or appliance, sensing the presence of a user of a fixture or sensing the flow of hot or tempered water to a fixture fitting or appliance.
Electric heat trace systems shall comply with IEEE 515.1 or UL 515. Controls for such systems shall automatically adjust the energy input to the heat tracing to maintain the desired water temperature in the piping in accordance with the times when heated water is used in the occupancy.

Insulation for service hot water piping with a thermal resistance, R-value, of not less than R-3 shall be applied to the following:

  1. Piping 3/4 inch (19.1 mm) and larger in nominal diameter located inside the conditioned space.
  2. Piping serving more than one dwelling unit.
  3. Piping located outside the conditioned space.
  4. Piping from the water heater to a distribution manifold.
  5. Piping located under a floor slab.
  6. Buried piping.
  7. Supply and return piping in circulation and recirculation systems other than cold water pipe return demand recirculation systems.
Where installed, drain water heat recovery units shall comply with CSA B55.2. Drain water heat recovery units shall be tested in accordance with CSA B55.1. Potable water-side pressure loss of drain water heat recovery units shall be less than 3 psi (20.7 kPa) for individual units connected to one or two showers. Potable water-side pressure loss of drain water heat recovery units shall be less than 2 psi (13.8 kPa) for individual units connected to three or more showers.
The buildings complying with Section R402.4.1 shall be provided with ventilation that complies with the requirements of Section M1505 the International Residential Code or International Mechanical Code, as applicable, or with other approved means of ventilation. Outdoor air intakes and exhausts shall have automatic or gravity dampers that close when the ventilation system is not operating.
Dwelling units shall be provided with a heat recovery or energy recovery ventilation system in Climate Zones 7 and 8. The system shall be balanced with a minimum sensible heat recovery efficiency of 65 percent at 32°F (0°C) at a flow greater than or equal to the design airflow.
Fans used to provide whole-dwelling mechanical ventilation shall meet the efficacy requirements of Table R403.6.2 at one or more rating points. Fans shall be tested in accordance with HVI 916 and listed. The airflow shall be reported in the product listing or on the label. Fan efficacy shall be reported in the product listing or shall be derived from the input power and airflow values reported in the product listing or on the label. Fan efficacy for fully ducted HRV, ERC, balanced, and in-line fans shall be determined at a static pressure of not less than 0.2 inch w.c. (49.85 Pa). Fan efficacy for ducted range hoods, bathroom and utility room fans shall be determined at a static pressure of not less than 0.1 inch w.c. (24.91 Pa).

TABLE R403.6.2

WHOLE-DWELLING MECHANICAL VENTILATION SYSTEM FAN EFFICACYa

FAN LOCATION AIRFLOW RATE MINIMUM (CFM) MINIMUM EFFICACY (CFM/WATT)
HRV, ERV Any 1.2 cfm/watt
In-line supply or exhaust fan Any 3.8 cfm/watt
Other exhaust fan < 90 2.8 cfm/watt
Other exhaust fan ≥ 90 3.5 cfm/watt
Air-handler that is integrated to tested and listed HVAC equipment Any 1.2 cfm/watt

For SI: 1 cubic foot per minute = 28.3 L/min.

  1.  Design outdoor airflow rate/watts of fan used.
Mechanical ventilation systems shall be tested and verified to provide the minimum ventilation flow rates required by Section R403.6. Testing shall be performed according to the ventilation equipment manufacturer's instructions, or by using a flow hood or box, flow grid, or other airflow measuring device at the mechanical ventilation fan's inlet terminals or grilles, outlet terminals or grilles, or in the connected ventilation ducts. Where required by the code official, testing shall be conducted by an approved third party. A written report of the results of the test shall be signed by the party conducting the test and provided to the code official.

Exception: Kitchen range hoods that are ducted to the outside with 6-inch (152 mm) or larger duct and not more than one 90-degree (1.57 rad) elbow or equivalent in the duct run.

Heating and cooling equipment shall be sized in accordance with ACCA Manual S based on building loads calculated in accordance with ACCA Manual J or other approved heating and cooling calculation methodologies. New or replacement heating and cooling equipment shall have an efficiency rating equal to or greater than the minimum required by federal law for the geographic location where the equipment is installed.
Systems serving multiple dwelling units shall comply with Sections C403 and C404 of the International Energy Conservation Code—Commercial Provisions instead of Section R403.
Snow- and ice-melting systems, supplied through energy service to the building, shall include automatic controls capable of shutting off the system when the pavement temperature is greater than 50°F (10°C) and precipitation is not falling, and an automatic or manual control that will allow shutoff when the outdoor temperature is greater than 40°F (4.8°C).
The energy consumption of pools and permanent spas shall be controlled by the requirements in Sections R403.10.1 through R403.10.3.
The electric power to heaters shall be controlled by an on-off switch that is an integral part of the heater mounted on the exterior of the heater in a location with ready access, or external to and within 3 feet (914 mm) of the heater. Operation of such switch shall not change the setting of the heater thermostat. Such switches shall be in addition to a circuit breaker for the power to the heater. Gas-fired heaters shall not be equipped with continuously burning ignition pilots.

Time switches or other control methods that can automatically turn  heaters and pump motors off and on according to a preset schedule shall be installed for heaters and pump motors. Heaters and pump motors that have built-in time switches shall be in compliance with this section.

Exceptions:

  1. Where public health standards require 24-hour pump operation.
  2. Pumps that operate solar- and waste-heat-recovery pool heating systems.

Outdoor heated pools and outdoor permanent spas shall be provided with a vapor-retardant cover or other approved vapor-retardant means.

Exception: Where more than 75 percent of the energy for heating, computed over an operation season of not fewer than 3 calendar months, is from a heat pump or an on-site renewable energy system, covers or other vapor-retardant means shall not be required.

The energy consumption of electric-powered portable spas shall be controlled by the requirements of APSP 14.
Where installed, the energy consumption of residential swimming pools and permanent residential spas shall be controlled in accordance with the requirements of APSP 15.
All permanently installed lighting fixtures, excluding kitchen appliance lighting fixtures, shall contain only high-efficacy lighting sources.
Connected exterior lighting for residential buildings shall comply with Section C405.5.

Exceptions:

  1. Detached one- and two- family dwellings.
  2. Townhouses.
  3. Solar-powered lamps not connected to any electrical service.
  4. Luminaires controlled by a motion sensor.
  5. Lamps and luminaires that comply with Section R404.1.
Fuel gas lighting systems shall not have continuously burning pilot lights.
Permanently installed lighting fixtures shall be controlled with either a dimmer, an occupant sensor control or other control that is installed or built into the fixture. 

Exception: Lighting controls shall not be required for the following:

  1. Bathrooms.
  2. Hallways.
  3. Exterior lighting fixtures.
  4. Lighting designed for safety or security.
Where the total permanently installed exterior lighting power is greater than 30 watts, the permanently installed exterior lighting shall comply with the following:
  1. Lighting shall be controlled by a manual on and off switch which permits automatic shut-off actions.

    Exception: Lighting serving multiple dwelling units.

  2. Lighting shall be automatically shut off when daylight is present and satisfies the lighting needs.
  3. Controls that override automatic shut-off actions shall not be allowed unless the override automatically returns automatic control to its normal operation within 24 hours.
This section establishes criteria for compliance using total building performance analysis. Such analysis shall include heating, cooling, mechanical ventilation and service water-heating energy only.

Compliance  based on total building performance requires that a proposed design meets all of the following:

  1. The requirements of the sections indicated within Table R405.2.
  2. The building thermal envelope shall be greater than or equal to levels of efficiency and solar heat gain coefficients in Table R402.1.1 or R402.1.3 of the 2009 International Energy Conservation Code.
  3. An annual energy cost that is less than or equal to the annual energy cost of the standard reference design. Energy prices shall be taken from a source approved by the code official, such as the Department of Energy, Energy Information Administration's State Energy Data System Prices and Expenditures reports. Code officials shall be permitted to require time-of-use pricing in energy cost calculations.

    Exception: The energy use based on source energy expressed in Btu or Btu per square foot of conditioned floor area shall be permitted to be substituted for the energy cost. The source energy multiplier for electricity shall be 3.16. The source energy multiplier for fuels other than electricity shall be 1.1.

TABLE R405.2

REQUIREMENTS FOR TOTAL BUILDING PERFORMANCE

SECTIONa TITLE
General
R401.2.5 Additional energy efficiency
R401.3 Certificate
Building Thermal Envelope
R402.1.1 Vapor retarder
R402.2.3 Eave baffle
R402.2.4.1 Access hatches and doors
R402.2.10.1 Crawl space wall insulation installations
R402.4.1.1 Installation
R402.4.1.2 Testing
R402.5 Maximum fenestration U-factor and SHGC
Mechanical
R403.1 Controls
R403.3, including R403.3.1, except Sections R403.3.2, R403.3.3 and R403.6 Ducts
R403.4 Mechanical system piping insulation
R403.5.1 Heated water circulation and temperature maintenance systems
R403.5.3 Drain water heat recovery units
R403.6 Mechanical ventilation
R403.7 Equipment sizing and efficiency rating
R403.8 Systems serving multiple dwelling units
R403.9 Snow melt and ice systems
R403.10 Energy consumption of pools and spas
R403.11 Portable spas
R403.12 Residential pools and permanent residential spas
Electrical Power and Lighting Systems
R404.1 Lighting equipment
R404.2 Interior lighting controls
  1. Reference to a code section includes all the relative subsections except as indicated in the table.
Documentation of the software used for the performance design and the parameters for the building shall be in accordance with Sections R405.3.1 through R405.3.2.2.
Documentation verifying that the methods and accuracy of the compliance software tools conform to the provisions of this section shall be provided to the code official.

Compliance software tools shall generate a report that documents that the proposed design complies with Section R405.3. A compliance report on the proposed design shall be submitted with the application for the building permit. Upon completion of the building, a confirmed compliance report based on the confirmed condition of the building shall be submitted to the code official before a certificate of occupancy is issued.

Compliance reports shall include information in accordance with Sections R405.3.2.1 and R405.3.2.2.

A compliance report submitted with the application for building permit shall include the following:

  1. Building street address, or other building site identification.
  2. The name of the individual performing the analysis and generating the compliance report.
  3. The name and version of the compliance software tool.
  4. Documentation of all inputs entered into the software used to produce the results for the reference design and/or the rated home.
  5. A certificate indicating that the proposed design complies with Section R405.3. The certificate shall document the building components' energy specifications that are included in the calculation including: component-level insulation R-values or U-factors; duct system and building envelope air leakage testing assumptions; and the type and rated efficiencies of proposed heating, cooling, mechanical ventilation and service water-heating equipment to be installed. If on-site renewable energy systems will be installed, the certificate shall report the type and production size of the proposed system.
  6. Where a site-specific report is not generated, the proposed design shall be based on the worst-case orientation and configuration of the rated home.

A compliance report submitted for obtaining the certificate of occupancy shall include the following:

  1. Building street address, or other building site identification.
  2. Declaration of the total building performance path on the title page of the energy report and the title page of the building plans.
  3. A statement, bearing the name of the individual performing the analysis and generating the report, indicating that the as-built building complies with Section R405.3
  4. The name and version of the compliance software tool.
  5. A site-specific energy analysis report that is in compliance with Section R405.3.
  6. A final confirmed certificate indicating compliance based on inspection, and a statement indicating that the confirmed rated design of the built home complies with Section R405.3. The certificate shall report the energy features that were confirmed to be in the home, including component level insulation R-values or U-factors; results from any required duct system and building envelope air leakage testing; and the type and rated efficiencies of the heating, cooling, mechanical ventilation and service water-heating equipment installed.
  7. When on-site renewable energy systems have been installed, the certificate shall report the type and production size of the installed system.
Calculations of the performance design shall be in accordance with Sections R405.4.1 and R405.4.2.
Except as specified by this section, the standard reference design and proposed design shall be configured and analyzed using identical methods and techniques.
The standard reference design and proposed design shall be configured and analyzed as specified by Table R405.4.2(1). Table R405.4.2(1) shall include, by reference, all notes contained in Table R402.1.3.

TABLE R405.4.2(1)

SPECIFICATIONS FOR THE STANDARD REFERENCE AND PROPOSED DESIGNS

BUILDING COMPONENT STANDARD REFERENCE DESIGN PROPOSED DESIGN
Above-grade walls Type: mass where the proposed wall is a mass wall; otherwise wood frame. As proposed
Gross area: same as proposed. As proposed
U-factor: as specified inTable R402.1.2. As proposed
Solar absorptance = 0.75. As proposed
Emittance = 0.90. As proposed
Basement and crawl space walls Type: same as proposed. As proposed
Gross area: same as proposed. As proposed
U-factor: as specified inTable R402.1.2, with the insulation layer on the interior side of the walls. As proposed
Above-grade floors Type: wood frame. As proposed
Gross area: same as proposed. As proposed
U-factor: as specified inTable R402.1.2. As proposed
Ceilings Type: wood frame. As proposed
Gross area: same as proposed. As proposed
U-factor: as specified inTable R402.1.2. As proposed
Roofs Type: composition shingle on wood sheathing. As proposed
Gross area: same as proposed. As proposed
Solar absorptance = 0.75. As proposed
Emittance = 0.90. As proposed
Attics Type: vented with an aperture of 1 ft2 per 300 ft2 of ceiling area. As proposed
Foundations Type: same as proposed. As proposed
Foundation wall area above and below grade and soil characteristics: same as proposed. As proposed
Opaque doors Area: 40 ft2. As proposed
Orientation: North. As proposed
U-factor: same as fenestration as specified inTable R402.1.2. As proposed
Vertical fenestration other than opaque doors Total areah =

(a) The proposed glazing area, where the proposed glazing area is less than 15 percent of the conditioned floor area.

(b) 15 percent of the conditioned floor area, where the proposed glazing area is 15 percent or more of the conditioned floor area.

As proposed
Orientation: equally distributed to four cardinal compass orientations (N, E, S & W). As proposed
U-factor: as specified inTable R402.1.2. As proposed
SHGC: as specified inTable R402.1.2 except for climate zones without an SHGC requirement, the SHGC shall be equal to 0.40. As proposed
Interior shade fraction: 0.92 — (0.21 × SHGC for the standard reference design). Interior shade fraction: 0.92 — (0.21 × SHGC as proposed)
External shading: none As proposed
Skylights None As proposed
Thermally isolated sunrooms None As proposed
Air exchange rate The air leakage rate at a pressure of 0.2 inch w.g. (50 Pa) shall be

Climate Zones 0 through 2: 5.0 air changes per hour.

Climate Zones 3 through 8: 3.0 air changes per hour.
The measured air exchange rate.a
The mechanical ventilation rate shall be in addition to the air leakage rate and shall be the same as in the proposed design, but not greater than 0.01 × CFA + 7.5 × (Nbr + 1)

where:

CFA = conditioned floor area, ft2.

Nbr = number of bedrooms.

The mechanical ventilation system type shall be the same as in the proposed design. Energy recovery shall not be assumed for mechanical ventilation.
The mechanical ventilation rateb shall be in addition to the air leakage rate and shall be as proposed.
Mechanical ventilation Where mechanical ventilation is not specified in the proposed design: None

Where mechanical ventilation is specified in the proposed design, the annual vent fan energy use, in units of kWh/yr, shall equal (1/ef) ×[0.0876 × CFA + 65.7 × (Nbr+1)]

where:

ef = the minimum fan efficacy, as specified in Table 403.6.2, corresponding to the system type at a flow rate of 0.01 × CFA + 7.5 × (Nbr+1)

CFA = conditioned floor area, ft2.

Nbr = number of bedrooms.

As proposed
Internal gains IGain, in units of Btu/day per dwelling unit, shall equal 17,900 + 23.8 ×CFA + 4,104 × Nbr

where:

CFA = conditioned floor area, ft2.

Nbr = number of bedrooms.

Same as standard reference design.
Internal mass Internal mass for furniture and contents: 8 pounds per square foot of floor area. Same as standard reference design, plus any additional mass specifically designed as a thermal storage elementc but not integral to the building envelope or structure.
Structural mass For masonry floor slabs: 80 percent of floor area covered by R-2 carpet and pad, and 20 percent of floor directly exposed to room air. As proposed
For masonry basement walls: as proposed, but with insulation as specified in Table R402.1.3, located on the interior side of the walls. As proposed
For other walls, ceilings, floors, and interior walls: wood frame construction. As proposed
Heating systemsd, e For other than electric heating without a heat pump: as proposed.

Where the proposed design utilizes electric heating without a heat pump, the standard reference design shall be an air source heat pump meeting the requirements of Section C403 of the IECC—Commercial Provisions.

Capacity: sized in accordance with Section R403.7.
As proposed
Cooling systemsd, f As proposed.

Capacity: sized in accordance with Section R403.7.
As proposed
Service water heatingd, g As proposed.

Use, in units of gal/day = 25.5 + (8.5 × Nbr)

where:
Nbr= number of bedrooms.
As proposed

Use, in units of gal/day = 25.5 + (8.5 × Nbr) × (1 — HWDS)

where:

Nbr
= number of bedrooms.

HWDS = factor for the compactness of the hot water distribution system.
Compactness ratioi factor HWDS
1 story 2 or more stories  
> 60% > 30% 0
> 30% to ≤ 60% > 15% to ≤ 30% 0.05
> 15% to ≤ 30% > 7.5% to ≤ 15% 0.10
< 15% < 7.5% 0.15
Thermal distribution systems Duct insulation: in accordance with Section R403.3.1.

A thermal distribution system efficiency (DSE) of 0.88 shall be applied to both the heating and cooling system efficiencies for all systems other than tested duct systems.

Duct location: same as proposed design.

Exception: For nonducted heating and cooling systems that do not have a fan, the standard reference design thermal distribution system efficiency (DSE) shall be 1. For tested duct systems, the leakage rate shall be 4 cfm (113.3 L/min) per 100 ft2 (9.29 m2) of conditioned floor area at a pressure of differential of 0.1 inch w.g. (25 Pa).

Duct location: as proposed

Duct insulation: as proposed.

As tested or, where not tested, as specified in Table R405.4.2(2).

Thermostat Type: Manual, cooling temperature setpoint = 75°F;

Heating temperature setpoint = 72°F.

Same as standard reference design.

Dehumidistat Where a mechanical ventilation system with latent heat recovery is not specified in the proposed design:
None.
Where the proposed design utilizes a mechanical ventilation system with latent heat recovery:

Dehumidistat type: manual, setpoint = 60% relative humidity.

Dehumidifier: whole-dwelling with integrated energy factor = 1.77 liters/kWh.

Same as standard reference design.

For SI: 1 square foot = 0.93 m2, 1 British thermal unit = 1055 J, 1 pound per square foot = 4.88 kg/m2, 1 gallon (US) = 3.785 L, °C = (°F — 32)/1.8, 1 degree = 0.79 rad.

  1. Where required by the code official, testing shall be conducted by an approved party. Hourly calculations as specified in the ASHRAE Handbook of Fundamentals, or the equivalent, shall be used to determine the energy loads resulting from infiltration.
  2. The combined air exchange rate for infiltration and mechanical ventilation shall be determined in accordance with Equation 43 of 2001 ASHRAE Handbook of Fundamentals, page 26.24 and the "Whole-house Ventilation" provisions of 2001 ASHRAE Handbook of Fundamentals, page 26.19 for intermittent mechanical ventilation.
  3. Thermal storage element shall mean a component that is not part of the floors, walls or ceilings that is part of a passive solar system, and that provides thermal storage such as enclosed water columns, rock beds, or phase-change containers. A thermal storage element shall be in the same room as fenestration that faces within 15 degrees (0.26 rad) of true south, or shall be connected to such a room with pipes or ducts that allow the element to be actively charged.
  4. For a proposed design with multiple heating, cooling or water heating systems using different fuel types, the applicable standard reference design system capacities and fuel types shall be weighted in accordance with their respective loads as calculated by accepted engineering practice for each equipment and fuel type present.
  5. For a proposed design without a proposed heating system, a heating system having the prevailing federal minimum efficiency shall be assumed for both the standard reference design and proposed design.
  6. For a proposed design home without a proposed cooling system, an electric air conditioner having the prevailing federal minimum efficiency shall be assumed for both the standard reference design and the proposed design.
  7. For a proposed design with a nonstorage-type water heater, a 40-gallon storage-type water heater having the prevailing federal minimum energy factor for the same fuel as the predominant heating fuel type shall be assumed. For a proposed design without a proposed water heater, a 40-gallon storage-type water heater having the prevailing federal minimum efficiency for the same fuel as the predominant heating fuel type shall be assumed for both the proposed design and standard reference design.
  8. For residences with conditioned basements, R-2 and R-4 residences, and for townhouses, the following formula shall be used to determine glazing area: 

    AF = As × FA × F

     where:

     AF = Total glazing area.

     As = Standard reference design total glazing area.

     FA = (Above-grade thermal boundary gross wall area)/(above-grade boundary wall area + 0.5 × below-grade boundary wall area).

     F = (above-grade thermal boundary wall area)/(above-grade thermal boundary wall area + common wall area) or 0.56, whichever is greater.

     and where:

     Thermal boundary wall is any wall that separates conditioned space from unconditioned space or ambient conditions.

     Above-grade thermal boundary wall is any thermal boundary wall component not in contact with soil.

     Below-grade boundary wall is any thermal boundary wall in soil contact.

     Common wall area is the area of walls shared with an adjoining dwelling unit.

  9. The factor for the compactness of the hot water distribution system is the ratio of the area of the rectangle that bounds the source of hot water and the fixtures that it serves (the "hot water rectangle") divided by the floor area of the dwelling.

    1. Sources of hot water include water heaters, or in multiple-family buildings with central water heating systems, circulation loops or electric heat traced pipes.
    2. The hot water rectangle shall include the source of hot water and the points of termination of all hot water fixture supply piping.
    3. The hot water rectangle shall be shown on the floor plans and the area shall be computed to the nearest square foot.
    4. Where there is more than one water heater and each water heater serves different plumbing fixtures and appliances, it is permissible to establish a separate hot water rectangle for each hot water distribution system and add the area of these rectangles together to determine the compactness ratio. 
    5. The basement or attic shall be counted as a story when it contains the water heater.
    6. Compliance shall be demonstrated by providing a drawing on the plans that shows the hot water distribution system rectangle(s), comparing the area of the rectangle(s) to the area of the dwelling and identifying the appropriate compactness ratio and HWDS factor.

TABLE R405.4.2(2)

DEFAULT DISTRIBUTION SYSTEM EFFICIENCIES FOR PROPOSED DESIGNSa

DISTRIBUTION SYSTEM CONFIGURATION AND CONDITION FORCED AIR SYSTEMS HYDRONIC SYSTEMSb
Distribution system components located in unconditioned space 0.95
Untested distribution systems entirely located in conditioned spacec 0.88 1
"Ductless" systemsd 1
  1. Default values in this table are for untested distribution systems, which must still meet minimum requirements for duct system insulation.
  2. Hydronic systems shall mean those systems that distribute heating and cooling energy directly to individual spaces using liquids pumped through closed-loop piping and that do not depend on ducted, forced airflow to maintain space temperatures.
  3. Entire system in conditioned space shall mean that no component of the distribution system, including the air-handler unit, is located outside of the conditioned space.
  4. Ductless systems shall be allowed to have forced airflow across a coil but shall not have any ducted airflow external to the manufacturer's air-handler enclosure.
Calculation software, where used, shall be in accordance with Sections R405.5.1 through R405.5.3.

Calculation procedures used to comply with this section shall be software tools capable of calculating the annual energy consumption of all building elements that differ between the standard reference design and the proposed design and shall include the following capabilities:

  1. Computer generation of the standard reference design using only the input for the proposed design. The calculation procedure shall not allow the user to directly modify the building component characteristics of the standard reference design.
  2. Calculation of whole-building (as a single zone) sizing for the heating and cooling equipment in the standard reference design residence in accordance with Section R403.7.
  3. Calculations that account for the effects of indoor and outdoor temperatures and part-load ratios on the performance of heating, ventilating and air-conditioning equipment based on climate and equipment sizing.
  4. Printed code official inspection checklist listing each of the proposed design component characteristics from Table R405.4.2(1) determined by the analysis to provide compliance, along with their respective performance ratings such as R-value, U-factor, SHGC, HSPF, AFUE, SEER and EF.
Performance analysis tools meeting the applicable provisions of Section R405 shall be permitted to be approved. Tools are permitted to be approved based on meeting a specified threshold for a jurisdiction. The code official shall be permitted to approve such tools for a specified application or limited scope.
When calculations require input values not specified by Sections R402, R403, R404 and R405, those input values shall be taken from an approved source.
This section establishes criteria for compliance using an Energy Rating Index (ERI) analysis.
Compliance based on the ERI requires that the rated design meets all of the following:
  1. The requirements of the sections indicated within Table R406.2.
  2. Maximum ERI of Table R406.5.

TABLE R406.2

REQUIREMENTS FOR ENERGY RATING INDEX

SECTIONa TITLE
General
R401.2.5

Additional efficiency packages

R401.3

Certificate

Building Thermal Envelope
R402.1.1

Vapor retarder

R402.2.3 Eave baffle
R402.2.4.1 Access hatches and doors
R402.2.10.1 Crawl space wall insulation installation
R402.4.1.1 Installation
R402.4.1.2 Testing
Mechanical
R403.1

Controls

R403.3 except Sections R403.3.2, R403.3.3 and R403.3.6

Ducts

R403.4

Mechanical system piping insulation

R403.5.1

Heated water calculation and temperature maintenance systems

R403.5.3

Drain water heat recovery units

R403.6

Mechanical ventilation

R403.7

Equipment sizing and efficiency rating

R403.8

Systems serving multiple dwelling units

R403.9

Snow melt and ice systems

R403.10

Energy consumption of pools and spas

R403.11

Portable spas

R403.12

Residential pools and permanent residential spas

Electrical Power and Lighting Systems
R404.1

Lighting equipment

R404.2

Interior lighting controls

R406.3

Building thermal envelope

  1. Reference to a code section includes all of the relative subsections except as indicated in the table.
Building and portions thereof shall comply with Section R406.3.1 or R406.3.2.
Where on-site renewable energy is not included for compliance using the ERI analysis of Section R406.4, the proposed total building thermal envelope UA, which is sum of U-factor times assembly area, shall be less than or equal to the building thermal envelope UA using the prescriptive U-factors from Table R402.1.2 multiplied by 1.15 in accordance with Equation 4-1. The area-weighted maximum fenestration SHGC permitted in Climate Zones 0 through 3 shall be 0.30. 
(Equation 4-1)
Where on-site renewable energy is included for compliance using the ERI analysis of Section R406.4, the building thermal envelope shall be greater than or equal to the levels of efficiency and SHGC in Table R402.1.2 or Table R402.1.4 of the 2018 International Energy Conservation Code.

The Energy Rating Index (ERI) shall be determined in accordance with RESNET/ICC 301 except for buildings covered by the International Residential Code, the ERI reference design ventilation rate shall be in accordance with Equation 4-2.

(Equation 4-2)

Energy used to recharge or refuel a vehicle used for transportation on roads that are not on the building site shall not be included in the ERI reference design or the rated design. For compliance purposes, any reduction in energy use of the rated design associated with on-site renewable energy shall not exceed 5 percent of the total energy use.

Compliance based on an ERI analysis requires that the rated proposed design and confirmed built dwelling be shown to have an ERI less than or equal to the appropriate value indicated in Table R406.5 when compared to the ERI reference design.

TABLE R406.5

MAXIMUM ENERGY RATING INDEX

CLIMATE ZONE ENERGY RATING INDEX
0-1 52
2 52
3 51
4 54
5 55
6 54
7 53
8 53

Verification of compliance with Section R406 as outlined in Sections R406.4 and R406.6 shall be completed by an approved third party. Verification of compliance with Section R406.2 shall be completed by the authority having jurisdiction or an approved third-party inspection agency in accordance with Section R105.4.
Documentation of the software used to determine the ERI and the parameters for the residential building shall be in accordance with Sections R406.7.1 through R406.7.4.
Software tools used for determining ERI shall be Approved Software Rating Tools in accordance with RESNET/ICC 301.
Compliance software tools shall generate a report that documents that the home and the ERI score of the rated design complies with Sections R406.2, R406.3 and R406.4. Compliance documentation shall be created for the proposed design and shall be submitted with the application for the building permit. Confirmed compliance documents of the built dwelling unit shall be created and submitted to the code official for review before a certificate of occupancy is issued. Compliance reports shall include information in accordance with Sections R406.7.2.1 and R406.7.2.2.
Compliance reports submitted with the application for a building permit shall include the following:
  1. Building street address, or other building site identification.
  2. Declare ERI on title page and building plans.
  3. The name of the individual performing the analysis and generating the compliance report.
  4. The name and version of the compliance software tool.
  5. Documentation of all inputs entered into the software used to produce the results for the reference design and/or the rated home.
  6. A certificate indicating that the proposed design has an ERI less than or equal to the appropriate score indicated in Table R406.5 when compared to the ERI reference design. The certificate shall document the building component energy specifications that are included in the calculation, including: component level insulation R-values or U-factors; assumed duct system and building envelope air leakage testing results; and the type and rated efficiencies of proposed heating, cooling, mechanical ventilation, and service water-heating equipment to be installed. If on-site renewable energy systems will be installed, the certificate shall report the type and production size of the proposed system.
  7. When a site-specific report is not generated, the proposed design shall be based on the worst-case orientation and configuration of the rated home.
A confirmed compliance report submitted for obtaining the certificate of occupancy shall be made site and address specific and include the following:
  1. Building street address or other building site identification.
  2. Declaration of ERI on title page and on building plans.
  3. The name of the individual performing the analysis and generating the report.
  4. The name and version of the compliance software tool.
  5. Documentation of all inputs entered into the software used to produce the results for the reference design and/or the rated home.
  6. A final confirmed certificate indicating that the confirmed rated design of the built home complies with Sections R406.2 and R406.4. The certificate shall report the energy features that were confirmed to be in the home, including: component-level insulation R-values or U-factors; results from any required duct system and building envelope air leakage testing; and the type and rated efficiencies of the heating, cooling, mechanical ventilation, and service water-heating equipment installed. Where on-site renewable energy systems have been installed on or in the home, the certificate shall report the type and production size of the installed system.
Where on-site renewable energy is included in the calculation of an ERI, one of the following forms of documentation shall be provided to the code official:
  1. Substantiation that the RECs associated with the on-site renewable energy are owned by, or retired on behalf of, the homeowner.
  2. A contract that conveys to the homeowner the RECs associated with the on-site renewable energy, or conveys to the homeowner an equivalent quantity of RECs associated with other renewable energy.

The code official shall be permitted to require the following documents:

  1. Documentation of the building component characteristics of the ERI reference design.
  2. A certification signed by the builder providing the building component characteristics of the rated design.
  3. Documentation of the actual values used in the software calculations for the rated design.
Performance analysis tools meeting the applicable subsections of Section R406 shall be approved. Documentation demonstrating the approval of performance analysis tools in accordance with Section R406.7.1 shall be provided.
Where calculations require input values not specified by Sections R402, R403, R404 and R405, those input values shall be taken from RESNET/ICC 301.
This section establishes alternative criteria for residential buildings in the tropical region at elevations less than 2,400 feet (731.5 m) above sea level.

 Compliance with this section requires the following:

  1. Not more than one-half of the occupied space is air conditioned.
  2. The occupied space is not heated.
  3. Solar, wind or other renewable energy source supplies not less than 80 percent of the energy for service water heating.
  4. Glazing in conditioned spaces has a solar heat gain coefficient (SHGC) of less than or equal to 0.40, or has an overhang with a projection factor equal to or greater than 0.30.
  5. Permanently installed lighting is in accordance with Section R404.
  6. The exterior roof surface complies with one of the options in Table C402.3 of the International Energy Conservation Code—Commercial Provisionsor the roof or ceiling has insulation with an R-value of R-15 or greater. Where attics are present, attics above the insulation are vented and attics below the insulation are unvented.
  7. Roof surfaces have a slope of not less than 1/4 unit vertical in 12 units horizontal (21-percent slope). The finished roof does not have water accumulation areas.
  8. Operable fenestration provides a ventilation area of not less than 14 percent of the floor area in each room. Alternatively, equivalent ventilation is provided by a ventilation fan.
  9. Bedrooms with exterior walls facing two different directions have operable fenestration on exterior walls facing two directions.
  10. Interior doors to bedrooms are capable of being secured in the open position.
  11. A ceiling fan or ceiling fan rough-in is provided for bedrooms and the largest space that is not used as a bedroom.
This section establishes additional efficiency package options to achieve additional energy efficiency in accordance with Section R401.2.5.
Additional efficiency package options for compliance with Section R401.2.1 are set forth in Sections R408.2.1 through R408.2.5.
The total building thermal envelope UA, the sum of U-factor times assembly area, shall be less than or equal to 95 percent of the total UA resulting from multiplying the U-factors in Table R402.1.2 by the same assembly area as in the proposed building. The UA calculation shall be performed in accordance with Section R402.1.5. The area-weighted average SHGC of all glazed fenestration shall be less than or equal to 95 percent of the maximum glazed fenestration SHGC in Table R402.1.2.
Heating and cooling equipment shall meet one of the following efficiencies:
  1. Greater than or equal to 95 AFUE natural gas furnace and 16 SEER air conditioner.
  2. Greater than or equal to 10 HSPF/16 SEER air source heat pump.
  3. Greater than or equal to 3.5 COP ground source heat pump.
For multiple cooling systems, all systems shall meet or exceed the minimum efficiency requirements in this section and shall be sized to serve 100 percent of the cooling design load. For multiple heating systems, all systems shall meet or exceed the minimum efficiency requirements in this section and shall be sized to serve 100 percent of the heating design load.
The hot water system shall meet one of the following efficiencies:
  1. Greater than or equal to .82 EF fossil fuel service water-heating system.
  2. Greater than or equal to 2.0 EF electric service water-heating system.
  3. Greater than or equal to 0.4 solar fraction solar water-heating system.
The thermal distribution system shall meet one of the following efficiencies:
  1. 100 percent of ducts and air handlers located entirely within the building thermal envelope.
  2. 100 percent of ductless thermal distribution system or hydronic thermal distribution system located completely inside the building thermal envelope.
  3. 100 percent of duct thermal distribution system located in conditioned space as defined by Section R403.3.2.
The measured air leakage rate shall be less than or equal to 3.0 ACH50, with either an Energy Recovery Ventilator (ERV) or Heat Recovery Ventilator (HRV) installed. Minimum HRV and ERV requirements, measured at the lowest tested net supply airflow, shall be greater than or equal to 75 percent Sensible Recovery Efficiency (SRE), less than or equal to 1.1 cubic feet per minute per watt (0.03 m3/min/watt) and shall not use recirculation as a defrost strategy. In addition, the ERV shall be greater than or equal to 50 percent Latent Recovery/Moisture Transfer (LRMT).
UpCodes Premium
Leverage the most sophisticated code compliance platform.
TRY FREE FOR TWO WEEKS VISIT PRICING