- Sections R401 through R404.
- Section R405 and the provisions of Sections R401 through R404 labeled "Mandatory."
- An energy rating index (ERI) approach in Section R406.
Residential buildings in the tropical zone at elevations below 2,400 feet (731.5 m) above sea level shall be deemed to comply with this chapter where the following conditions are met:
- Not more than one-half of the occupied space is air conditioned.
- The occupied space is not heated.
- Solar, wind or other renewable energy source supplies not less than 80 percent of the energy for service water heating.
- Glazing in conditioned space has a solar heat gain coefficient of less than or equal to 0.40, or has an overhang with a projection factor equal to or greater than 0.30.
- Permanently installed lighting is in accordance with Section R404.
- The exterior roof surface complies with one of the options in Table C402.3 or the roof/ceiling has insulation with an R-value of R-15 or greater. If present, attics above the insulation are vented and attics below the insulation are unvented.
- Roof surfaces have a minimum slope of 1/4 inch per foot of run. The finished roof does not have water accumulation areas.
- Operable fenestration provides ventilation area equal to not less than 14 percent of the floor area in each room. Alternatively, equivalent ventilation is provided by a ventilation fan.
- Bedrooms with exterior walls facing two different directions have operable fenestration on exterior walls facing two direction exterior walls.
- Interior doors to bedrooms are capable of being secured in the open position.
- A ceiling fan or ceiling fan rough-in is provided for bedrooms and the largest space that is not used as a bedroom.
- 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.
- Those that do not contain conditioned space.
TABLE R402.1.2 INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENTa
CLIMATE ZONE | FENESTRATION U-FACTORb | SKYLIGHTb U-FACTOR | GLAZED FENESTRATION SHGCb, e | CEILING R-VALUE | WOOD FRAME WALL R-VALUE | MASS WALL R-VALUEi | FLOOR R-VALUE | BASEMENTc WALL R-VALUE | SLABd R-VALUE & DEPTH | CRAWL SPACEc WALL R-VALUE |
1 | NR | 0.75 | 0.25 | 30 | 13 | 3/4 | 13 | 0 | 0 | 0 |
2 | 0.40 | 0.65 | 0.25 | 38 | 13 | 4/6 | 13 | 0 | 0 | 0 |
3 | 0.35 | 0.55 | 0.25 | 38 | 20 or 13+5h | 8/13 | 19 | 5/13f | 0 | 5/13 |
4 except Marine | 0.35 | 0.55 | 0.40 | 49 | 20 or 13+5h | 8/13 | 19 | 10/13 | 10, 2 ft | 10/13 |
5 and Marine 4 | 0.32 | 0.55 | NR | 49 | 20 or 13+5h | 13/17 | 30g | 15/19 | 10, 2 ft | 15/19 |
6 | 0.32 | 0.55 | NR | 49 | 20+5 or 13+10h or 18 + 6.5h | 15/20 | 30g | 15/19 | 10, 4 ft | 15/19 |
7 and 8 | 0.32 | 0.55 | NR | 49 | 20+5 or 13+10h | 19/21 | 38g | 15/19 | 10, 4 ft | 15/19 |
For SI: 1 foot = 304.8 mm. |
a. R-values are minimums. U-factors and SHGC are maximums. When insulation is installed in a cavity which is less than the label or design thickness of the insulation, the installed R-value of the insulation shall not be less than the R-value specified in the table. |
b. The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration. Exception: Skylights may be excluded from glazed fenestration SHGC requirements in climate zones 1 through 3 where the SHGC for such skylights does not exceed 0.30. |
c. "15/19" means R-15 continuous insulation on the interior or exterior of the home or R-19 cavity insulation at the interior of the basement wall. "15/19" shall be permitted to be met with R-13 cavity insulation on the interior of the basement wall plus R-5 continuous insulation on the interior or exterior of the home. "10/13" means R-10 continuous insulation on the interior or exterior of the home or R-13 cavity insulation at the interior of the basement wall. |
d. R-5 shall be added to the required slab edge R-values for heated slabs. Insulation depth shall be the depth of the footing or 2 feet, whichever is less in Climate Zones 1 through 3 for heated slabs. |
e. There are no SHGC requirements in the Marine Zone. |
f. Basement wall insulation is not required in warm-humid locations as defined by Figure R301.1 and Table R301.1. |
g. Or insulation sufficient to fill the framing cavity, R-19 minimum. |
h. The first value is cavity insulation, the second value is continuous insulation, so "13+5" means R-13 cavity insulation plus R-5 continuous insulation. |
i. The second R-value applies when more than half the insulation is on the interior of the mass wall. |
j. R-18 insulation to be permitted in place of R-20 requirement provided the wall framing factor is 20% or less or exterior walls with 24" o.c. nominal vertical stud spacing. |
CLIMATE ZONE | FENESTRATION U-FACTOR | SKYLIGHT U-FACTOR | CEILING U-FACTOR | FRAME WALL U-FACTOR | MASS WALL U-FACTORb | FLOOR U-FACTOR | BASEMENT WALL U-FACTOR | CRAWL SPACE WALL U-FACTOR |
1 | 0.50 | 0.75 | 0.035 | 0.084 | 0.197 | 0.064 | 0.360 | 0.477 |
2 | 0.40 | 0.65 | 0.030 | 0.084 | 0.165 | 0.064 | 0.360 | 0.477 |
3 | 0.35 | 0.55 | 0.030 | 0.060 | 0.098 | 0.047 | 0.091c | 0.136 |
4 except Marine | 0.35 | 0.55 | 0.026 | 0.060 | 0.098 | 0.047 | 0.059 | 0.065 |
5 and Marine 4 | 0.32 | 0.55 | 0.026 | 0.060 | 0.082 | 0.033 | 0.050 | 0.055 |
6 | 0.32 | 0.55 | 0.026 | 0.045 | 0.060 | 0.033 | 0.050 | 0.055 |
7 and 8 | 0.32 | 0.55 | 0.026 | 0.045 | 0.057 | 0.028 | 0.050 | 0.055 |
- Nonfenestration U-factors shall be obtained from measurement, calculation or an approved source.
- When more than half the insulation is on the interior, the mass wall U-factors shall be a maximum of 0.17 in Climate Zone 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.
- Basement wall U-factor of 0.360 in warm-humid locations as defined by Figure R301.1 and Table R301.1.
TABLE R402.2.6 STEEL-FRAME CEILING, WALL AND FLOOR INSULATION (R-VALUE)
WOOD FRAME R-VALUE REQUIREMENT | COLD-FORMED STEEL 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-Framed Wall, 16" on center | |
R-13 | R-13 + 4.2 or R-19 + 2.1 or R-21 + 2.8 or R-0 + 9.3 or R-15 + 3.8 or R-21 + 3.1 |
R-13 + 3 | R-0 + 11.2 or R-13 + 6.1 or R-15 + 5.7 or R-19 + 5.0 or R-21 + 4.7 |
R-20 | R-0 + 14.0 or R-13 + 8.9 or R-15 + 8.5 or R-19 + 7.8 or R-19 + 6.2 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 Framed Wall, 24" on center | |
R-13 | R-0 + 9.3 or R-13 + 3.0 or R-15 + 2.4 |
R-13 + 3 | R-0 + 11.2 or R-13 + 4.9 or R-15 + 4.3 or R-19 + 3.5 or R-21 + 3.1 |
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 |
a Cavity insulation R-value is listed first, followed by continuous insulation R-value. |
b. Insulation exceeding the height of the framing shall cover the framing. |
Exception: The floor framing-cavity insulation shall be permitted to be in contact with the topside of sheathing or continuous insulation installed on the bottom side of floor framing where combined with insulation that meets or exceeds the minimum wood frame wall R-value in Table 402.1.2 and that extends from the bottom to the top of all perimeter floor framing members.
- The minimum ceiling insulation R-values shall be R-19 in Climate Zones 1 through 4 and R-24 in Climate Zones 5 through 8.
- The minimum wall R-value shall be R-13 in all climate zones. Walls separating a sunroom with a thermal isolation from conditioned space shall meet the building thermal envelope requirements of this code.
Dynamic glazing shall be permitted to satisfy the SHGC requirements of Table R402.1.2 provided 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 not be permitted.
TABLE R402.4.1.1 AIR BARRIER AND INSULATION INSTALLATION
COMPONENT | AIR BARRIER CRITERIA | INSULATION INSTALLATION CRITERIA |
General requirements | A continuous air barrier shall be installed in the building envelope. The exterior thermal envelope contains a continuous air barrier. 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/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 of R-3 per inch minimum. 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 window/door jambs and framing, and skylights and framing shall be sealed. | |
Rim joists | Rim joists shall include the air barrier. | Rim joists shall be insulated. |
Floors (including above garage and cantilevered floors) | 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, or floor framing cavity insulation shall be permitted to be in contact with the top side of sheathing, or continuous insulation installed on the underside of floor framing and extends from the bottom to the top of all perimeter floor framing members. |
Crawl space walls | Exposed earth in unvented crawl spaces shall be covered with a Class I vapor retarder with overlapping joints taped. | Where provided instead of floor insulation, insulation shall be permanently attached to the crawlspace walls. |
Shafts, penetrations | Duct shafts, utility penetrations, and flue shafts opening to exterior or unconditioned space shall be sealed. | |
Narrow cavities | Batts in narrow cavities shall be cut to fit, or narrow cavities shall be filled by insulation that on installation readily conforms to the available cavity space. | |
Garage separation | Air sealing shall be provided between the garage and conditioned spaces. | |
Recessed lighting | Recessed light fixtures installed in the building thermal envelope shall be sealed to the drywall. | Recessed light fixtures installed in the building thermal envelope shall be air tight and IC rated. |
Plumbing and wiring | Batt insulation shall be cut neatly to fit around wiring and plumbing in exterior walls, or insulation that on installation readily conforms to available space shall extend behind piping and wiring. | |
Shower/tub on exterior wall | The air barrier installed at exterior walls adjacent to showers and tubs shall separate them from the showers and tubs. | Exterior walls adjacent to showers and tubs shall be insulated. |
Electrical/phone box on exterior walls | The air barrier shall be installed behind electrical or communication boxes or air-sealed boxes shall be installed. | |
HVAC register boots | HVAC register boots that penetrate building thermal envelope shall be sealed to the subfloor or drywall. | |
Concealed sprinklers | When 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. |
During testing:
- Exterior windows and doors, fireplace and stove doors shall be closed, but not sealed, beyond the intended weatherstripping or other infiltration control measures.
- Dampers including exhaust, intake, makeup air, backdraft and flue dampers shall be closed, but not sealed beyond intended infiltration control measures.
- Interior doors, if installed at the time of the test, shall be open.
- Exterior doors for continuous ventilation systems and heat recovery ventilators shall be closed and sealed.
- Heating and cooling systems, if installed at the time of the test, shall be turned off.
- Supply and return registers, if installed at the time of the test, shall be fully open.
Exception: Site-built windows, skylights and doors.
Exceptions:
- Direct vent appliances with both intake and exhaust pipes installed continuous to the outside.
- Fireplaces and stoves complying with Section R402.4.2 and Section R1006 of the International Residential Code.
Exception: Ducts or portions thereof located completely inside the building thermal envelope.
Exceptions:
1. Air-impermeable spray foam products shall be permitted to be applied without additional joint seals.
2 For ducts having a static pressure classification of less than 2 inches of water column (500 Pa), additional closure systems shall not be required for continuously welded joints and seams, and locking-type joints and seams of other than the snap-lock and button-lock types.
- 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. All registers shall be taped or otherwise sealed during the test.
- 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.
A written report of the results of the test shall be signed by the party conducting the test and provided to the code official.
- Rough-in test: The total leakage shall be less than or equal to 4 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 cubic feet per minute (85 L/min) per 100 square feet (9.29 m2) of conditioned floor area.
- Postconstruction test: Total leakage shall be less than or equal to 4 cubic feet per minute (113.3 L/min) per 100 square feet (9.29 m2) of conditioned floor area.
Where supply and return air ducts are partially or completely buried in ceiling insulation, such ducts shall comply with all of the following:
- The supply and return ducts shall have an insulation R-value not less than R-8.
- 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.
In Climate Zones 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.
For ducts to be considered as inside a conditioned space, such ducts shall comply with either of the following:
- The duct system shall be located completely within the continuous air barrier and within the building thermal envelope.
The ducts shall be buried within ceiling insulation in accordance with Section R403.3.6 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 R403.3.4, 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.
- The control shall 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.
- The control shall limit the temperature of the water entering the cold water piping to 104°F (40°C).
- Piping 3/4 inch (19.1 mm) and larger in nominal diameter.
- Piping serving more than one dwelling unit.
- Piping located outside the conditioned space.
- Piping from the water heater to a distribution manifold.
- Piping located under a floor slab.
- Buried piping.
- Supply and return piping in recirculation systems other than demand recirculation systems.
FAN LOCATION | AIR FLOW RATE MINIMUM (CFM) |
MINIMUM EFFICACYa (CFM/WATT) |
AIR FLOW RATE MAXIMUM (CFM) |
Range hoods | Any | 2.8 cfm/watt | Any |
In-line fan | Any | 2.8 cfm/watt | Any |
Bathroom, utility room | 10 | 1.4 cfm/watt | < 90 |
Bathroom, utility room | 90 | 2.8 cfm/watt | Any |
- When tested in accordance with HVI Standard 916
Exceptions:
- Where public health standards require 24-hour pump operation.
- Pumps that operate solar- and waste-heat-recovery pool heating systems.
Exception: Low-voltage lighting.
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.
Compliance reports shall include information in accordance with Sections R405.4.2.1 and R405.4.2.2. Where the proposed design of a building could be built on different sites where the cardinal orientation of the building on each site is different, compliance of the proposed design for the purposes of the application for the building permit shall be based on the worst-case orientation, worst-case configuration, worst-case building air leakage and worst-case duct leakage. Such worst-case parameters shall be used as inputs to the compliance software for energy analysis.
- Building street address, or other building site identification.
- A statement indicating that the proposed design complies with Section R405.3.
- An inspection checklist documenting the building component characteristics of the proposed design as indicated in Table R405.5.2(1). The inspection checklist shall show results for both the standard reference design and the proposed design with user inputs to the compliance software to generate the results.
- A site-specific energy analysis report that is in compliance with Section R405.3.
- The name of the individual performing the analysis and generating the report.
- The name and version of the compliance software tool.
- Building street address, or other building site identification.
- A statement indicating that the as-built building complies with Section R405.3.
- A certificate indicating that the building passes the performance matrix for code compliance and listing the energy saving features of the buildings.
- A site-specific energy analysis report that is in compliance with Section R405.3.
- The name of the individual performing the analysis and generating the report.
- The name and version of the compliance software tool.
- Documentation of the building component characteristics of the standard reference design.
- A certification signed by the builder providing the building component characteristics of the proposed design as given in Table R405.5.2(1).
- Documentation of the actual values used in the software calculations for the proposed design.
TABLE R405.5.2(1) SPECIFICATIONS FOR THE STANDARD REFERENCE AND PROPOSED DESIGNS
BUILDING COMPONENT | STANDARD REFERENCE DESIGN | PROPOSED DESIGN |
Above-grade walls | Type: mass wall if proposed wall is mass; otherwise wood frame. | As proposed |
Gross area: same as proposed | As proposed | |
U-factor: as specified in Table R402.1.4 | 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: from Table R402.1.4, with insulation layer on interior side of walls | As proposed | |
Above-grade floors | Type: wood frame | As proposed |
Gross area: same as proposed | As proposed | |
U-factor: as specified in Table R402.1.4 | As proposed | |
Ceilings | Type: wood frame | As proposed |
Gross area: same as proposed | As proposed | |
U-factor: as specified in Table R402.1.4 | 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 aperture = 1 ft2 per 300 ft2 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 from Table R402.1.4 | 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 in Table R402.1.4 | As proposed | |
SHGC: as specified in Table R402.1.2 except that for climates with no requirement (NR) SHGC = 0.40 shall be used. | As proposed | |
Interior shade fraction: 0.92-(0.21 × SHGC for the standard reference design) | 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 | Air leakage rate of 5 air changes per hour in climate zones 1 and 2, and 3 air changes per hour in climate zones 3 through 8 at a pressure of 0.2 inches w.g (50 Pa). The mechanical ventilation rate shall be in addition to the air leakage rate and the same as in the proposed design, but no greater than 0.01 × CFA + 7.5 × (Nbr + 1) where: CFA = conditioned floor area Nbr = number of bedrooms Energy recovery shall not be assumed for mechanical ventilation. | For residences that are not tested, the same air leakage rate as the standard reference design. For tested residences, the measured air exchange ratea. The mechanical ventilation rateb shall be in addition to the air leakage rate and shall be as proposed. |
TABLE R405.5.2(1)—continued SPECIFICATIONS FOR THE STANDARD REFERENCE AND PROPOSED DESIGNS
BUILDING COMPONENT | STANDARD REFERENCE DESIGN | PROPOSED DESIGN |
Mechanical ventilation | None, except where mechanical ventilation is specified by the proposed design, in which case: Annual vent fan energy use: kWh/yr = 0.03942 × CFA + 29.565 × (Nbr + 1) where: CFA = conditioned floor area Nbr = number of bedrooms | As proposed |
Internal gains | IGain = 17,900 + 23.8 × CFA + 4104 × Nbr (Btu/day per dwelling unit) | Same as standard reference design. |
Internal mass | An internal mass for furniture and contents of 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 required by Table R402.1.4 located on the interior side of the walls | As proposed | |
For other walls, for ceilings, floors, and interior walls, wood frame construction | As proposed | |
Heating systemsd, e | As proposed for other than electric heating without a heat pump, 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, e, f, g | As proposed Use: same as proposed design | As proposed gal/day = 30 + (10 × Nbr) |
Thermal distribution systems | Duct insulation: From Section R403.2.1 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. 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 inches w.g. (25 Pa). | As tested or as specified in Table R405.5.2(2) if not tested. Duct insulation shall be as proposed. |
Thermostat | Type: Manual, cooling temperature setpoint = 75°F; Heating temperature setpoint = 72°F | Same as standard reference |
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.
- 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.
- 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.
- Thermal storage element shall mean a component 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 must be in the same room as fenestration that faces within 15 degrees (0.26 rad) of true south, or must be connected to such a room with pipes or ducts that allow the element to be actively charged.
- 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.
- For a proposed design without a proposed heating system, a heating system with the prevailing federal minimum efficiency shall be assumed for both the standard reference design and proposed design.
- For a proposed design home without a proposed cooling system, an electric air conditioner with the prevailing federal minimum efficiency shall be assumed for both the standard reference design and the proposed design.
- For a proposed design with a nonstorage-type water heater, a 40-gallon storage-type water heater with the prevailing federal minimum energy factor for the same fuel as the predominant heating fuel type shall be assumed. For the case of a proposed design without a proposed water heater, a 40-gallon storage-type water heater with 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.
- For residences with conditioned basements, R-2 and R-4 residences and 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. 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.L and CFA are in the same units.
TABLE R405.5.2(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 | — |
For SI: 1 cubic foot per minute = 0.47 L/s, 1 square foot = 0.093 m2, 1 pound per square inch = 6895 Pa, 1 inch water gauge = 1250 Pa.
- Default values given by this table are for untested distribution systems, which must still meet minimum requirements for duct system insulation.
- 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.
- 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.
- 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.
- 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.
- 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 R403.6.
- 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.
- Printed code official inspection checklist listing each of the proposed design component characteristics from Table R405.5.2(1) determined by the analysis to provide compliance, along with their respective performance ratings (R-value, U-factor, SHGC, HSPF, AFUE, SEER, EF are some examples).
Exception: Supply and return ducts not completely inside the building thermal envelope shall be insulated to a minimum of R-6.
The proposed residential building shall be shown to have an annual total normalized modified load less than or equal to the annual total loads of the ERI reference design.
CLIMATE ZONE | ENERGY RATING INDEX |
1 | 52 |
2 | 52 |
3 | 51 |
4 | 54 |
5 | 55 |
6 | 54 |
7 | 53 |
8 | 53 |
CLIMATE ZONE | ENERGY RATING INDEXa |
1 | 57 |
2 | 57 |
3 | 57 |
4 | 62 |
5 | 61 |
6 | 61 |
7 | 58 |
8 | 58 |
- Where on-site renewable energy is included for compliance using the ERI analysis of Section R406.4, the building shall meet the mandatory requirements of Section R406.2, and 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 2015 International Energy Conservation Code.
- Address or other identification of the residential building.
- An inspection checklist documenting the building component characteristics of the rated design. The inspection checklist shall show results for both the ERI reference design and the rated design, and shall document all inputs entered by the user necessary to reproduce the results.
- Name of individual completing the compliance report.
- Name and version of the compliance software tool.
- Documentation of the building component characteristics of the ERI reference design.
- A certification signed by the builder providing the building component characteristics of the rated design.
- Documentation of the actual values used in the software calculations for the rated design.
- Computer generation of the ERI reference design using only the input for the rated design.
The calculation procedure shall not allow the user to directly modify the building component characteristics of the ERI reference design. - Calculation of whole building, as a single zone, sizing for the heating and cooling equipment in the ERI reference design residence in accordance with Section R403.7.
- 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.
- Printed code official inspection checklist listing each of the rated design component characteristics determined by the analysis to provide compliance, along with their respective performance ratings.