ADOPTS WITH AMENDMENTS:

International Residential Code 2009 (IRC 2009)

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

Chapter 11 Energy Efficiency

AMENDMENT
This section has been amended at the state or city level.
This chapter has been revised in its entirety; there will be no marginal markings or underlines.

Section N1101 General

AMENDMENT
This section has been amended at the state or city level.

Section N1101 Scope, General Requirements, and Additional Definitions

AMENDMENT
This section has been amended at the state or city level.

N1101.1 Scope

AMENDMENT
This section has been amended at the state or city level.

This chapter shall regulate the design and construction of buildings for the effective use of energy. This code is intended to provide flexibility to permit the use of innovative approaches and techniques to achieve the effective use of energy. This code is not intended to prevent the use of any material, method of construction, design or insulating system not specifically prescribed herein, provided that such construction, design or insulating system has been approved by the code official as meeting the intent of this code.

Exception: Portions of the building envelope that do not enclose conditioned space.

N1101.1.2 Existing Buildings

AMENDMENT
This section has been amended at the state or city level.
Except as specified in this chapter, this code shall not be used to require the removal, alteration or abandonment of, nor prevent the continued use and maintenance of, an existing building or building system lawfully in existence at the time of adoption of this code.

N1101.1.3 Additions, Alterations, Renovations or Repairs

AMENDMENT
This section has been amended at the state or city level.
Additions, alterations, renovations or repairs to an existing building, building system or portion thereof shall conform to the provisions of this code as they relate to new construction without requiring the unaltered portion(s) of the existing building or building system to comply with this code. Additions, alterations, renovations or repairs shall not create an unsafe or hazardous condition or overload existing building systems. An addition shall be deemed to comply with this code if the addition alone complies or if the existing building and addition comply with this code as a single building.

Exception:
  1. The following need not comply provided the energy use of the building is not increased:

    1. Storm windows installed over existing fenestration.
    2. Incidental repairs requiring a new sash or new glazing.
    3. Existing ceiling, wall or floor cavities exposed during construction provided that these cavities are filled with insulation.
    4. Construction where the existing roof, wall or floor cavity is not exposed.
  2. Converting unconditioned attic space to conditioned attic space. Ceilings shall be insulated to a minimum of R-30, walls shall be insulated to the exterior wall requirements in Table N1102.1 and follow backing requirements in Section N1102.2.12.

N1101.2 Compliance

AMENDMENT
This section has been amended at the state or city level.

Compliance shall be demonstrated by either meeting the requirements of the North Carolina Energy Conservation Code or meeting the requirements of this chapter. Climate zones from Figures N1101.2(1), Figure N1101.2(2) or Table N1101.2 shall be used in determining the applicable requirements from this chapter. Projects shall comply with Sections N1101, N1102.4, N1102.5, and N1103.1, N1103.2.2, N1103.2.3, and N1103.3 through N1103.9 and either:

  1. Sections N1102.1 through N1102.3, N1103.2.1 and N1104.1; or
  2. North Carolina specific REScheck shall be permitted to demonstrate compliance with this code. Envelope requirements may not be traded off against the use of high efficiency heating and/or cooling equipment. No trade-off calculations are needed for required termite inspection and treatment gaps.
FIGURE N1101.2(1)
NORTH CAROLINA CLIMATE ZONES

FIGURE N1101.2(2)
CLIMATE ZONES
TABLE N1101.2
NORTH CAROLINA CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID DESIGNATIONS BY COUNTY Key: A — Moist, B — Dry, C — Marine. Absence of moisture designation indicates moisture regime is irrelevant. Asterisk (*) indicates a warm-humid location.
NORTH
CAROLINA
3A Craven 3A Johnston 3A Richmond
3A Cumberland 3A Jones 3A Robeson
4A Alamance 3A Currituck 4A Lee 4A Rockingham
4A Alexander 3A Dare 3A Lenoir 3A Rowan
5A Alleghany 3A Davidson 4A Lincoln 4A Rutherford
3A Anson 4A Davie 4A Macon 3A Sampson
5A Ashe 3A Duplin 4A Madison 3A Scotland
5A Avery 4A Durham 3A Martin 3A Stanly
3A Beaufort 3A Edgecombe 4A McDowell 4A Stokes
4A Bertie 4A Forsyth 3A Mecklenburg 4A Surry
3A Bladen 4A Franklin 5A Mitchell 4A Swain
3A Brunswick* 3A Gaston 3A Montgomery 4A Transylvania
4A Buncombe 4A Gates 3A Moore 3A Tyrrell
4A Burke 4A Graham 4A Nash 3A Union
3A Cabarrus 4A Granville 3A New Hanover* 4A Vance
4A Caldwell 3A Greene 4A Northampton 4A Wake
3A Camden 4A Guilford 3A Onslow* 4A Warren
3A Carteret* 4A Halifax 4A Orange 3A Washington
4A Caswell 4A Harnett 3A Pamlico 5A Watauga
4A Catawba 4A Haywood 3A Pasquotank 3A Wayne
4A Chatham 4A Henderson 3A Pender* 4A Wilkes
4A Cherokee 4A Hertford 3A Perquimans 3A Wilson
3A Chowan 3A Hoke 4A Person 4A Yadkin
4A Clay 3A Hyde 3A Pitt 5A Yancey
4A Cleveland 4A Iredell 4A Polk
3A Columbus* 4A Jackson 3A Randolph
Warm humid counties are identified in Table N1101.2 by an asterisk.

N1101.2.2 Change in Space Conditioning

AMENDMENT
This section has been amended at the state or city level.
Any nonconditioned space that is altered to become conditioned space shall be required to be brought into full compliance with this code.
Exceptions:
  1. Existing enclosed ceiling, wall or floor cavities comply provided that these cavities are filled with insulation.
  2. See N1101.1.3, Exception 2.
Materials, systems and equipment shall be identified in a manner that will allow a determination of compliance with the applicable provisions of this chapter.

N1101.4 Building Thermal Envelope Insulation

AMENDMENT
This section has been amended at the state or city level.
An R-value identification mark shall be applied by the manufacturer to each piece of building thermal envelope insulation 12 inches (305 mm) or greater in width. Alternately, the insulation installers shall provide a certification listing the type, manufacturer and R-value of insulation installed in each element of the building thermal envelope. For blown or sprayed insulation (fiberglass and cellulose), the initial installed thickness, settled thickness, settled R-value, installed density, coverage area and number of bags installed shall be listed on the certification. For sprayed polyurethane foam (SPF) insulation, the installed thickness of the areas covered and R-value of installed thickness shall be listed on the certification. The insulation installer shall sign, date and post the certification in a conspicuous location on the job site.

N1101.4.1 Blown or Sprayed Roof/Ceiling Insulation

AMENDMENT
This section has been amended at the state or city level.
The thickness of blown-in or sprayed roof/ceiling insulation (fiberglass or cellulose) shall be written in inches (mm) on markers that are installed at least one for every 300 square feet (28 m2) throughout the attic space. The markers shall be affixed to the trusses or joists and marked with the minimum initial installed thickness with numbers a minimum of 1 inch (25 mm) in height. Each polyurethane foam thickness and installed R-value shall be listed on certification provided by the insulation installer.
Insulating materials shall be installed such that the manufacturer's R-value mark is readily observable upon inspection.

N1101.5 Fenestration Product Rating

AMENDMENT
This section has been amended at the state or city level.

U-factors of fenestration products (windows, doors and skylights) shall be determined in accordance with NFRC 100 by an accredited, independent laboratory, and labeled and certified by the manufacturer. Products lacking such a labeled U-factor shall be assigned a default U-factor from Tables N1101.5(1) or N1101.5(2). The solar heat gain coefficient (SHGC) of glazed fenestration products (windows, glazed doors and skylights) shall be determined in accordance with NFRC 200 by an accredited, independent laboratory, and labeled and certified by the manufacturer. Products lacking such a labeled SHGC shall be assigned a default SHGC from Table N1101.5(3).

TABLE N1101.5(1)
DEFAULT GLAZED FENESTRATION U-FACTORS

FRAME TYPE

SINGLE PANE

DOUBLE PANE

SKYLIGHT

Single

Double

Metal

1.2

0.8

2

1.3

Metal with thermal break

1.1

0.65

1.9

1.1

Nonmetal or metal clad

0.95

0.55

1.75

1.05

Glazed block

0.6


TABLE N1101.5(2)
DEFAULT DOOR U-FACTORS

DOOR TYPE

U-FACTOR

Uninsulated metal

1.2

Insulated metal

0.6

Wood

0.5

Insulated, nonmetal edge, max 45% glazing, any glazing double pane

0.35


TABLE N1101.5(3)
DEFAULT GLAZED FENESTRATION SHGC

SINGLE GLAZED

DOUBLE GLAZED

GLAZED BLOCK

Clear

Tinted

Clear

Tinted

0.8

0.7

0.7

0.6

0.6

N1101.6 Insulation Product Rating

AMENDMENT
This section has been amended at the state or city level.
The thermal resistance (R-value) of insulation shall be determined in accordance with the U.S. Federal Trade Commission R-value rule (CFR Title 16, Part 460, May 31, 2005) in units of h × ft2 ×°F/Btu at a mean temperature of 75°F (24°C).

N1101.7 Installation

AMENDMENT
This section has been amended at the state or city level.
All materials, systems and equipment shall be installed in accordance with the manufacturer's installation instructions and this code.

N1101.7.1 Protection of Exposed Foundation Insulation

AMENDMENT
This section has been amended at the state or city level.
Insulation applied to the exterior of basement walls, crawlspace walls and the perimeter of slab-on-grade floors shall have a rigid, opaque and weather-resistant protective covering to prevent the degradation of the insulation's thermal performance. The protective covering shall cover the exposed exterior insulation and extend a minimum of 6 inches (153 mm) below grade.

N1101.8 Above Code Programs

AMENDMENT
This section has been amended at the state or city level.

N1101.9 Certificate

AMENDMENT
This section has been amended at the state or city level.

A permanent certificate shall be posted on or in the electrical distribution panel, in the attic next to the attic insulation card, or inside a kitchen cabinet or other approved location. The certificate shall not cover or obstruct the visibility of the circuit directory label, service disconnect label or other required labels. The builder, permit holder, or registered design professional shall be responsible for completing the certificate. The certificate shall list the predominant R-values of insulation installed in or on ceiling/roof, walls, foundation (slab, basement wall, crawlspace wall and floor) and ducts outside conditioned spaces; U-factors for fenestration and the solar heat gain coefficient (SHGC) of fenestration.

   Where there is more than one value for each component, the certificate shall list the value covering the largest area. The certificate shall indicate whether the building air leakage was visually inspected as required in Section N1102.4.2.1 or provide results of the air leakage testing required in Section N1102.4.2.2 The certificate shall provide results of duct leakage test required in Section N1102.4.2.2. Appendix E-1 contains a sample certificate.



N1101.10 Additional Voluntary Criteria for Increasing Residential Energy Efficiency

AMENDMENT
This section has been amended at the state or city level.
Appendix E-4 contains additional voluntary measures for increasing residential energy efficiency beyond code minimums. Implementation of the increased energy efficiency measures is strictly voluntary at the option of the permit holder. The sole purpose of the appendix is to provide guidance for achieving additional residential energy efficiency improvements that have been evaluated to be those that are most cost effective for achieving an additional 15-20 percent improvement in energy efficiency beyond code minimums.

N1102.1 Insulation and Fenestration Criteria

AMENDMENT
This section has been amended at the state or city level.
The building thermal envelope shall meet the requirements of Table N1102.1 based on the climate zone specified in Table N1101.2.

TABLE N1102.1
INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENTa

CLIMATE
ZONE

FENESTRATION
U -FACTORb,l

SKYLIGHTb
U-FACTOR

GLAZED
FENESTRATION
SHGCb, e, m

CEILING
R -VALUEk

WOOD
FRAME
WALL
R -VALUEe

MASS
WALL
R -VALUEi

FLOOR
R-VALUE

BASEMENTc
WALL
R-VALUE

SLABd
R-VALUE
AND DEPTH

CRAWL
SPACEc

WALL
R-VALUE

3

0.35

0.65

0.30

30

13

5/10

19

10/13f

0

5/13

4

0.35

0.60

0.30

38 or 30 cont.j

15
13 + 2.5h

5/10

19

10/13

10d

10/13

5

0.35

0.60

NR

38 or 30 cont.j

15,
13 + 5, or
15 + 3e,h

13/17

30g

10/13

10d

10/13

For SI: 1 foot = 304.8 mm.
  1. R-values are minimums. U-factors and SHGC are maximums.
  2. The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration.
  3. "10/13" means R-10 continuous insulated sheathing on the interior or exterior of the home or R-13 cavity insulation at the interior of the basement wall or crawl space wall.
  4. For monolithic slabs, insulation shall be applied from the inspection gap downward to the bottom of the footing or a maximum of 18 inches below grade whichever is less. For floating slabs, insulation shall extend to the bottom of the foundation wall or 24 inches, whichever is less. (See Appendix O) R-5 shall be added to the required slab edge R-values for heated slabs.
  5. R-19 fiberglass batts compressed and installed in a nominal 2 × 6 framing cavity is deemed to comply. Fiberglass batts rated R-19 or higher compressed and installed in a 2 × 4 wall is not deemed to comply.
  6. Basement wall insulation is not required in warm-humid locations as defined by Figure N1101.2(1) and (2) and Table N1101.2.
  7. Or insulation sufficient to fill the framing cavity, R-19 minimum.
  8. "13+5" means R-13 cavity insulation plus R-5 insulated sheathing. 15+3 means R-15 cavity insulation plus R-3 insulated sheathing. If structural sheathing covers 25 percent or less of the exterior, insulating sheathing is not required where structural sheathing is used. If structural sheathing covers more than 25 percent of exterior, structural sheathing shall be supplemented with insulated sheathing of at least R-2. 13+2.5 means R-13 cavity insulation plus R-2.5 sheathing.
  9. For Mass Walls, the second R-value applies when more than half the insulation is on the interior of the mass wall.
  10. R-30 shall be deemed to satisfy the ceiling insulation requirement wherever the full height of uncompressed R-30 insulation extends over the wall top plate at the eaves. Otherwise R-38 insulation is required where adequate clearance exists or insulation must extend to either the insulation baffle or within 1" of the attic roof deck.
  11. Table value required except for roof edge where the space is limited by the pitch of the roof, there the insulation must fill the space up to the air baffle.
  12. In addition to the exemption in Section N1102.3.3, a maximum of two glazed fenestration product assemblies having a U-factor no greater than 0.55 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.
  13. In addition to the exemption in Section N1102.3.3, a maximum of two glazed fenestration product assemblies having a SHGC no greater than 0.70 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.
Insulation material used in layers, such as framing cavity insulation and insulating sheathing, shall be summed to compute the component R-value. The manufacturer's settled R-value shall be used for blown insulation.

Computed R-values shall not include an R-value for other building materials or air films.

N1102.1.2 U-factor Alternative

AMENDMENT
This section has been amended at the state or city level.

An assembly with a U-factor equal to or less than that specified in Table N1102.1.2 shall be permitted as an alternative to the R-value in Table N1102.1.

TABLE N1102.1.2
EQUIVALENT U-FACTORS
a

CLIMATE
ZONE

FENESTRATION
U -FACTORe

SKYLIGHT
U-FACTOR

CEILING
U-FACTOR

FRAME
WALL
U-FACTOR

MASS
WALL
U-FACTOR
b

FLOOR
U-FACTOR

BASEMENT
WALL
U- FACTORd

CRAWL
SPACE
WALL
U -FACTORc

3

0.35

0.65

0.035

0.082

0.141

0.047

0.059

0.136

4

0.35

0.60

0.030

0.077

0.141

0.047

0.059

0.065

5

0.35

0.60

0.030

0.061

0.082

0.033

0.059

0.065

  1. Nonfenestration U-factors shall be obtained from measurement, calculation or an approved source.
  2. When more than half the insulation is on the interior, the mass wall U-factors shall be a maximum 0.12 in Zone 3, 0.10 in Zone 4, and the same as the frame wall U-factor in zone 5.
  3. Basement wall U-factor of 0.360 in warm-humid locations as defined by Figures N1101.2(1), N1101.2(2) and Table N1101.2.
  4. Foundation U-factor requirements shown in Table N1102.1.2 include wall construction and interior air films but exclude soil conductivity and exterior air films. U-factors for determining code compliance in accordance with Section N1102.1.3 (total UA alternative) shall be modified to include soil conductivity and exterior air films.
  5. A maximum of two glazed fenestration product assemblies having a U-factor no greater than 0.55 and a SHGC no greater than 0.70 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty. When applying this note and using the REScheck "UA Trade-off" compliance method to allow continued use of the software, the applicable fenestration products shall be modeled as meeting the U-factor of 0.35 and the SHGC of 0.30, as applicable, but the fenestration products actual U-factor and actual SHGC shall be noted in the comments section of the software for documentation of application of this note to the applicable products. Compliance for these substitute products shall be verified compared to the allowed substituted maximum U-value requirement and maximum SHGC requirement, as applicable.
If the total building thermal envelope UA (sum of U-factor times assembly area) is less than or equal to the total UA resulting from using the U-factors in Table N1102.1.2 (multiplied by the same assembly area as in the proposed building), the building shall be considered in compliance with Table N1102.1. The UA calculation shall be done using a method consistent with the ASHRAE Handbook of Fundamentals and shall include the thermal bridging effects of framing materials. The SHGC requirements shall be met in addition to UA compliance.

N1102.2.1 Ceilings With Attic Spaces

AMENDMENT
This section has been amended at the state or city level.
Ceilings with attic spaces over conditioned space shall meet the insulation requirements in Table N1102.1.

Exceptions:
  1. When insulation is installed in a fully enclosed attic floor system, as described in Appendix E 2.1, R-30 shall be deemed compliant.
  2. In roof edge and other details such as bay windows, dormers, and similar areas where the space is limited, the insulation must fill the space up to the air baffle.

N1102.2.2 Ceilings Without Attic Spaces

AMENDMENT
This section has been amended at the state or city level.
Where the design of the roof/ceiling assembly, including cathedral ceilings, bay windows and other similar areas, does not allow sufficient space for the required insulation, the minimum required insulation for such roof/ceiling assemblies shall be R-30. This reduction of insulation from the requirements of Section N1102.1 shall be limited to 500 square feet (46 m2) of ceiling surface area. This reduction shall not apply to the U-factor alternative approach in Section N1102.1.2 and the Total UA alternative in Section N1102.1.3.

N1102.2.3 Access Hatches and Doors

AMENDMENT
This section has been amended at the state or city level.
Horizontal access doors from conditioned spaces to unconditioned spaces (e.g., attics and crawl spaces) shall be weatherstripped and insulated to an R-10 minimum value, and vertical doors to such spaces shall be weatherstripped and insulated to R-5. Access shall be provided to all equipment that prevents damaging or compressing the insulation. A wood framed or equivalent baffle or retainer is required to be provided when loose fill insulation is installed, the purpose of which is to prevent the loose fill insulation from spilling into the living space when the attic access is opened, and to provide a permanent means of maintaining the installed R-value of the loose fill insulation.

Exceptions:
  1. Pull down stair systems shall be weatherstripped and insulated with a minimum of R-5 insulation. The insulation shall not interfere with proper operation of the stair. Non-rigid insulation materials are not allowed. Additional insulation systems that enclose the stair system from above are allowed. Exposed foam plastic must meet the provisions of the North Carolina Residential Code.
  2. Full size doors that are part of the building thermal envelope and provide a passageway to unconditioned spaces shall meet the requirements of exterior doors in Section N1102.3.4.
Mass walls for the purposes of this chapter shall be considered above-grade walls of concrete block, concrete, insulated concrete form (ICF), masonry cavity, brick (other than brick veneer), earth (adobe, compressed earth block, rammed earth) and solid timber/logs.

N1102.2.5 Steel-Frame Ceilings, Walls and Floors

AMENDMENT
This section has been amended at the state or city level.

Steel-frame ceilings, walls and floors shall meet the insulation requirements of Table N1102.2.5 or shall meet the U-factor requirements in Table N1102.1.2. The calculation of the U-factor for a steel-frame envelope assembly shall use a series-parallel path calculation method.

TABLE N1102.2.5
STEEL-FRAME CEILING, WALL AND FLOOR INSULATION (R-VALUE)

WOOD FRAME R-VALUE REQUIREMENT

COLD-FORMED STEEL EQUIVALENT R-VALUEa

Steel Truss Ceilingsa

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

R-13

R-13 + 5 or R-15 + 4 or R-21 + 3

R-19

R-13 + 9 or R-19 + 8 or R-25 + 7

R-21

R-13 + 10 or R-19 + 9 or R-25 + 8

Steel Joist Floor

R-13

R-19 in 2 × 6

R-19 + R-6 in 2 × 8 or 2 × 10

R-19

R-19 + R-6 in 2 × 6

R-19 + R-12 in 2 × 8 or 2 × 10

For SI: 1 inch = 25.4 mm.

  1. Cavity insulation R-value is listed first, followed by continuous insulation R-value.
  2. Insulation exceeding the height of the framing shall cover the framing.

N1102.2.6 Floors

AMENDMENT
This section has been amended at the state or city level.
Floor insulation shall be installed to maintain permanent contact with the underside of the subfloor decking. The distance between tension support wires or other devices that hold the floor insulation in place against the subfloor shall be no more than 18 inches. In addition, supports shall be located no further than 6 inches from each end of the insulation.

Exception: Enclosed floor cavity such as garage ceilings, cantilevers or buildings on pilings with enclosed floor cavity with the insulation fully in contact with the lower air barrier. In this case, the band boards shall be fully insulated to maintain thermal envelope continuity.

N1102.2.7 Basement Walls

AMENDMENT
This section has been amended at the state or city level.
Walls associated with conditioned basements shall be insulated from the top of the basement wall down to 10 feet (3048 mm) below grade or to the basement floor, whichever is less. Walls associated with unconditioned basements shall meet this requirement unless the floor overhead is insulated in accordance with Sections N1102.1 and N1102.2.6.

N1102.2.8 Slab-On-Grade Floors

AMENDMENT
This section has been amended at the state or city level.
Slab-on-grade floors with a floor surface less than 12 inches (305 mm) below grade shall be insulated in accordance with Table N1102.1. 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. Slab edge insulation shall have 2 inch termite inspection gap consistent with Appendix O of this code.

N1102.2.9 Closed Crawl Space Walls

AMENDMENT
This section has been amended at the state or city level.
Where the floor above a closed crawl space is not insulated, the exterior crawlspace walls shall be insulated in accordance with table 1102.1.

   Wall insulation may be located in any combination of the outside and inside wall surfaces and within the structural cavities or materials of the wall system.

   Wall insulation requires that the exterior wall band joist area of the floor frame be insulated. Wall insulation shall begin 3 inches (76.2 mm) below the top of the masonry foundation wall and shall extend down to 3 inches (76.2 mm) above the top of the footing or concrete floor, 3 inches (76.2 mm ) above the interior ground surface or 24 inches (609.6 mm) below the outside finished ground level, whichever is less. (See Appendix E-2.2 details.)

   Termite inspection, clearance, and wicking gaps are allowed in wall insulation systems. Insulation may be omitted in the gap area without energy penalty. The allowable insulation gap widths are listed in Table N1102.2.9. If gap width exceeds the allowances, one of the following energy compliance options shall be met:
  1. Wall insulation is not allowed and the required insulation value shall be provided in the floor system.
  2. Compliance shall be demonstrated with energy trade-off methods provided by a North Carolina-specific version of RESCHECK.
TABLE N1102.2.9
WALL INSULATION ALLOWANCES FOR TERMITE TREATMENT AND INSULATION GAPS
MAXIMUM GAP
WIDTH (inches)
INSULATION
LOCATION
GAP
DESCRIPTION
3 Outside Above grade inspection
between top of insulation and bottom of siding
6 Outside Below grade treatment
4a Inside Wall inspection between top of insulation and bottom of sill
Clearance/wicking space
between bottom of insulation
and top of ground surface, footing, or concrete floor.
For SI: 1 inch = 25.4 mm.
  1. No insulation shall be required on masonry wall of 9 inches in height or less.
Insulation shall not be required on the horizontal portion of the foundation that supports a masonry veneer.

N1102.2.11 Thermally Isolated Conditioned Sunroom Insulation

AMENDMENT
This section has been amended at the state or city level.
The minimum ceiling insulation R-values shall be R-19 in zones 3 and 4, and R-24 in Zone 5. The minimum wall R-value shall be R-13. New wall(s) separating a sunroom from conditioned space shall meet the building thermal envelope requirements. Floor and slab insulation shall comply with values in Table N1102.1.

N1102.2.12 Framed Cavity Walls

AMENDMENT
This section has been amended at the state or city level.
The exterior thermal envelope wall insulation shall be installed in substantial contact and continuous alignment with the building envelope air barrier. Insulation shall be substantially free from installation gaps, voids, or compression. For framed walls, the cavity insulation shall be enclosed on all sides with a rigid material or an air barrier material. Wall insulation shall be enclosed at the following locations when installed on exterior walls prior to being covered by subsequent construction, consistent with Appendix E-2.3 of this code:
  1. Tubs
  2. Showers
  3. Stairs
  4. Fireplace units
   Enclosure of wall cavity insulation also applies to walls that adjoin attic spaces by placing a rigid material or air barrier material on the attic space side of the wall on the attic space side of the wall.
An area-weighted average of fenestration products shall be permitted to satisfy the U-factor requirements.

N1102.3.2 Glazed Fenestration SHGC

AMENDMENT
This section has been amended at the state or city level.
An area-weighted average of fenestration products more than 50 percent glazed shall be permitted to satisfy the SHGC requirements.
Up to 15 square feet (1.4 m2) of glazed fenestration per dwelling unit shall be permitted to be exempt from U-factor and SHGC requirements in Section N1102.1. This exemption shall not apply to the U-factor alternative approach in Section N1102.1.2 and the Total UA alternative in Section N1102.1.3.

N1102.3.4 Opaque Door Exemption

AMENDMENT
This section has been amended at the state or city level.
Opaque doors separating conditioned and unconditioned space shall have a maximum U-factor of 0.35.

Exception: One side-hinged opaque door assembly up to 24 square feet (2.22 m2) in area is exempted from the U-factor requirement in Section N1102.1. This exemption shall not apply to the U-factor alternative approach in Section N1102.1.2 and the Total UA alternative in Section N1102.1.3.

N1102.3.5 Thermally Isolated Conditioned Sunroom U-factor and SHGC

AMENDMENT
This section has been amended at the state or city level.
The maximum fenestration U-factor shall be 0.40 and the maximum skylight U-factor shall be 0.75. Sunrooms with cooling systems shall have a maximum fenestration SHGC of 0.40 for all glazing.

   New windows and doors separating the sunroom from conditioned space shall meet the building thermal envelope requirements. Sunroom additions shall maintain thermal isolation; and shall be served by a separate heating or cooling system, or be thermostatically controlled as a separate zone of the existing system.

Exception: A maximum of two glazed fenestration product assemblies having a U-factor no greater than 0.55 and, when cooling is provided, a SHGC no greater than 0.70 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.

N1102.3.6 Replacement Fenestration

AMENDMENT
This section has been amended at the state or city level.
Where an entire existing fenestration unit is replaced with a new fenestration product, including frame, sash and glazing, the replacement fenestration unit shall meet the applicable requirements for U-factor and SHGC in Table N1102.1.

N1102.4 Air Leakage Control

AMENDMENT
This section has been amended at the state or city level.

N1102.4.1 Building Thermal Envelope

AMENDMENT
This section has been amended at the state or city level.

The building thermal envelope shall be durably sealed with an air barrier system to limit infiltration. The sealing methods between dissimilar materials shall allow for differential expansion and contraction. For all homes, where present, the following shall be caulked, gasketed, weatherstripped or otherwise sealed with an air barrier material or solid material consistent with Appendix E-2.4 of this code:

  1. Blocking and sealing floor/ceiling systems and under knee walls open to unconditioned or exterior space.
  2. Capping and sealing shafts or chases, including flue shafts.
  3. Capping and sealing soffit or dropped ceiling areas.

N1102.4.2 Air Sealing and Insulation

AMENDMENT
This section has been amended at the state or city level.

Building envelope air tightness shall be demonstrated by Section N1102.4.2.1 or N1102.4.2.2. Appendix E-3 contains optional sample worksheets for visual inspection or testing for the permit holder's use only.

TABLE N1102.4.2
AIR BARRIER INSPECTION

COMPONENT

CRITERIA

Ceiling/attic

Sealants or gaskets provide a continuous air barrier system joining the top plate of framed walls with either the ceiling drywall or the top edge of wall drywall to prevent air leakage. Top plate penetrations are sealed.
For ceiling finishes that are not air barrier systems such as tongue-and-groove planks, air barrier systems,(for example, taped house wrap), shall be used above the finish
Note: It is acceptable that sealants or gaskets applied as part of the application of the drywall will not be observable by the code official.

Walls

Sill plate is gasketed or sealed to subfloor or slab.

Windows and doors

Space between window and exterior door jambs and framing is sealed.

Floors (including above garage and cantilevered floors)

Air barrier system is installed at any exposed edge of insulation.

Penetrations

Utility penetrations through the building thermal envelope, including those for plumbing, electrical wiring, ductwork, security and fire alarm wiring, and control wiring, shall be sealed.

Garage separation

Air sealing is provided between the garage and conditioned spaces. An air barrier system shall be installed between the ceiling system above the garage and the ceiling system of interior spaces.

Duct boots

Sealing HVAC register boots and return boxes to subfloor or drywall.

Recessed lighting

Recessed light fixtures are airtight, IC rated and sealed to drywall.
    Exception—fixtures in conditioned space.

N1102.4.2.1 Testing Option

AMENDMENT
This section has been amended at the state or city level.

N1102.4.2.1 Visual Inspection Option

AMENDMENT
This section has been amended at the state or city level.
Building envelope tightness shall be considered acceptable when items providing insulation enclosure in Section N1102.2.12 and air sealing in Section N1102.4.1 are addressed and when the items listed in Table N1102.4.2, applicable to the method of construction, are certified by the builder, permit holder or registered design professional via the certificate in Appendix E-1.

N1102.4.2.2 Visual Inspection Option

AMENDMENT
This section has been amended at the state or city level.

N1102.4.2.2 Testing Option

AMENDMENT
This section has been amended at the state or city level.
Building envelope tightness shall be considered acceptable when items providing insulation enclosure in Section N1102.2.12 and air sealing in Section N1102.4.1 are addressed and when tested air leakage is less than or equal to one of the two following performance measurements:
  1. 0.30 CFM50/square foot of surface area (SFSA) or
  2. Five (5) air changes per hour (ACH50)
When tested with a blower door fan assembly, at a pressure of 33.5 psf (50 Pa). A single point depressurization, not temperature corrected, test is sufficient to comply with this provision, provided that the blower door fan assembly has been certified by the manufacturer to be capable of conducting tests in accordance with ASTM E 779-03. Testing shall occur after rough in and after installation of penetrations of the building envelope, including penetrations for utilities, plumbing, electrical, ventilation and combustion appliances. Testing shall be reported by the permit holder, a NC licensed general contractor, a NC licensed HVAC contractor, a NC licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater.

During testing:
  1. Exterior windows and doors, fireplace and stove doors shall be closed, but not sealed;
  2. Dampers shall be closed, but not sealed, including exhaust, backdraft, and flue dampers;
  3. Interior doors shall be open;
  4. Exterior openings for continuous ventilation systems, air intake ducted to the return side of the conditioning system, and energy or heat recovery ventilators shall be closed and sealed;
  5. Heating and cooling system(s) shall be turned off; and
  6. Supply and return registers shall not be sealed.
   The air leakage information, including building air leakage result, tester name, date, and contact information, shall be included on the certificate described in Section N1101.9.

   For Test Criteria 1 above, the report shall be produced in the following manner: perform the blower door test and record the CFM50. Calculate the total square feet of surface area for the building thermal envelope (all floors, ceilings, and walls, including windows and doors, bounding conditioned space) and record the area. Divide CFM50 by the total square feet and record the result. If the result is less than or equal to 0.30 CFM50/SFSA the envelope tightness is acceptable; or

   For Test Criteria 2 above, the report shall be produced in the following manner: perform a blower door test and record the CFM50. Multiply the CFM50 by 60 minutes to create CFHour50 and record. Then calculate the total conditioned volume of the home and record. Divide the CFH50 by the total volume and record the result. If the result is less than or equal to 5 ACH50 the envelope tightness is acceptable.

N1102.4.3 Fireplaces

AMENDMENT
This section has been amended at the state or city level.
Site-built masonry fireplaces shall have dampers and comply with Section R1006 of the North Carolina Residential Code for combustion air.
Windows, skylights and sliding glass doors shall have an air infiltration rate of no more than 0.3 cfm per square foot (1.5 L/s/m2), and swinging doors no more than 0.5 cfm per square foot (2.6 L/s/m2), when tested according to 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.
Recessed luminaires installed in the building thermal envelope shall be sealed to limit air leakage between conditioned and unconditioned spaces. All recessed luminaires shall be IC-rated and labeled as meeting ASTM E 283 when tested at 1.57 psf (75 Pa) pressure differential with no more than 2.0 cfm (0.944 L/s) of air movement from the conditioned space to the ceiling cavity. All recessed luminaires shall be sealed with a gasket or caulk between the housing and the interior wall or ceiling covering.

N1102.5 Maximum Fenestration U-factor and SHGC

AMENDMENT
This section has been amended at the state or city level.
The area-weighted average maximum fenestration U-factor permitted using trade-offs from Section 1102.1.3 shall be 0.40. Maximum skylight U-factors shall be 0.65 in zones 4 and 5 and 0.60 in zone 3.

Exception: A maximum of two glazed fenestration product assemblies having a U-factor no greater than 0.55 and a SHGC no greater than 0.70 shall be permitted to be substituted for minimum code compliant fenestration product assemblies without penalty.

N1103.1 Controls

AMENDMENT
This section has been amended at the state or city level.
At least one thermostat shall be provided for each separate heating and cooling system.

N1103.1.1 Programmable Thermostat

AMENDMENT
This section has been amended at the state or city level.
Where the primary heating system is a forced-air furnace, at least one thermostat per 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 the day. This thermostat shall include the capability to set back or temporarily operate the system to maintain zone temperatures down to 55°F (13°C) or up to 85°F (29°C).

N1103.1.2 Heat Pump Supplementary Heat

AMENDMENT
This section has been amended at the state or city level.
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.

   A heat strip outdoor temperature lockout shall be provided to prevent supplemental heat operation in response to the thermostat being changed to a warmer setting. The lockout shall be set no lower than 35°F and no higher than 40°F.

Exception: In lieu of a heat strip outdoor temperature lockout, the following time and temperature electric-resistance control may be used. After six minutes of compressor run time in heat mode, supplemental electric heat shall energize only if the leaving air temperature from the indoor coil is below 90°F. If the indoor coil leaving air temperature exceeds 100°F, supplemental heat shall automatically de-energize, but allow the compressor to continue to operate until the call is satisfied. No thermostat shall initiate supplemental electric heat at any time. Thermostat controlled emergency heat shall not be limited by outdoor temperature. Electric resistance supplemental heat during defrost shall operate normally without limitation.

1103.1.3 Maintenance Information

AMENDMENT
This section has been amended at the state or city level.
Maintenance instructions shall be furnished for equipment and systems that require preventive maintenance.

N1103.2.1 Insulation

AMENDMENT
This section has been amended at the state or city level.
Supply and return ducts in unconditioned space and outdoors shall be insulated to R-8. Supply ducts inside semiconditioned space shall be insulated to R-4; return ducts inside conditioned and semi-conditioned space are not required to be insulated. Ducts located inside conditioned space are not required to be insulated other than as may be necessary for preventing the formation of condensation on the exterior of cooling ducts.

N1103.2.2 Sealing

AMENDMENT
This section has been amended at the state or city level.

All ducts, air handlers, filter boxes and building cavities used as ducts shall be sealed. Joints and seams shall comply with Part V—Mechanical, Section 603.9 of the North Carolina Residential Code. Duct testing shall be verified by compliance with Section 1103.2.2.1 or 1103.2.2.2.

1103.2.2.1 Total Duct Leakage

AMENDMENT
This section has been amended at the state or city level.
Total duct leakage less than or equal to 6 CFM (18 L/min) per 100 ft2 (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, including the manufacturer's air handler enclosure.

During testing:
  1. Block, if present, the ventilation air duct(s) connected to the conditioning system.
  2. The duct air leakage testing equipment shall be attached to the largest return in the system or to the air handler.
  3. The filter shall be removed and the air handler power shall be turned off.
  4. Supply boots or registers and return boxes or grilles shall be taped, plugged, or otherwise sealed air tight.
  5. The hose for measuring the 25 Pascals of pressure differential shall be inserted into the boot of the supply that is nominally closest to the air handler.
  6. Specific instructions from the duct testing equipment manufacturer shall be followed to reach duct test pressure and measure duct air leakage.

1103.2.2.2 Duct Leakage to the Outside

AMENDMENT
This section has been amended at the state or city level.
Conduct the test using fan pressurization of distribution system and building at a fixed reference pressure for combined supply and return leaks. Duct leakage to the outside shall be less than or equal to 6 CFM (12 L/min) per 100 ft2 (9.29 m2) of conditioned floor area served by that system when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, relative to the outside, including the manufacturer's air handler enclosure.

During testing:
  1. Block, if present, the ventilation air duct connected to the conditioning system.
  2. The duct air leakage testing equipment shall be attached to the largest return in the system or to the air handler.
  3. The filter shall be removed and the air handler power shall be turned off.
  4. Supply boots or registers and return boxes or grilles shall be taped, plugged, or otherwise sealed air tight or as tight as possible.
  5. The hose for measuring the 25 Pascals of pressure differential shall be inserted into the boot of the supply that is nominally closest to the air handler.
  6. Open all interconnecting doors in the building, close dampers for fireplaces and other operable dampers.
  7. Set up an envelope air moving/flow-regulating/flow measurement assembly, such as a blower door, following the manufacturer's prescribed procedure.
  8. Specific instructions from the duct testing equipment manufacturer shall be followed to reach duct test pressure and measure duct air leakage used in combination with a blower door. Typical steps are as follows:
    1. Depressurize the ductwork system to 25 Pa using the measurement hose in Step 5 above.
    2. Depressurize the house to 25 Pa using an envelope air moving/flow-regulating/flow measurement assembly, such as a blower door.
    3. Correct the duct pressure to measure 0 Pa of pressure differential between the house and the ductwork system.
    4. Read the CFM of duct leakage using the procedures for the specific equipment being used. (Note that most automatically calculating pressure gauges cannot compute the CFM25 automatically with a duct-to-house difference in pressure of 0 Pa, so the gauge setting should be set to read CFM instead of CFM25).
Duct testing shall be performed and reported by the permit holder, a North Carolina licensed general contractor, a North Carolina licensed HVAC contractor, a North Carolina licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater. A single point depressurization, not temperature corrected, test is sufficient to comply with this provision, provided that the duct testing fan assembly(s) has been certified by the manufacturer to be capable of conducting tests in accordance with ASTM E 1554-07.

The duct leakage information, including duct leakage result, tester name, date, and contact information, shall be included on the certificate described in Section N1101.9.

For the Test Criteria, the report shall be produced in the following manner: perform the HVAC system air leakage test and record the CFM25. Calculate the total square feet of Conditioned Floor Area (CFA) served by that system. Multiply the CFM25 by 100, then divide by the Conditioned Floor Area to find the CFM25/100SF and record the result. If the result is less than or equal to 6CFM25/100 SF the HVAC system air tightness is acceptable. Appendix E-3C contains optional sample worksheets for duct testing for the permit holder's use only.

Exceptions to testing requirements:
  1. Duct systems or portions thereof inside the building thermal envelope shall not be required to be leak tested.
  2. Installation of a partial system as part of replacement, renovation or addition does not require a duct leakage test.
Building framing cavities shall not be used as supply ducts.

N1103.3 Mechanical System Piping Insulation

AMENDMENT
This section has been amended at the state or city level.
Mechanical system piping capable of carrying fluids above 105°F (41°C) or below 55°F (13°C) shall be insulated to a minimum of R-3.
All circulating service hot water piping shall be insulated to at least R-2. Circulating hot water systems shall include an automatic or readily accessible manual switch that can turn off the hot water circulating pump when the system is not in use.

N1103.5 Mechanical Ventilation

AMENDMENT
This section has been amended at the state or city level.
Exhausts shall have automatic or gravity dampers that close when the ventilation system is not operating.

N1103.6 Equipment Sizing and Efficiency

AMENDMENT
This section has been amended at the state or city level.

N1103.6.1 Equipment Sizing

AMENDMENT
This section has been amended at the state or city level.
Heating and cooling equipment shall be sized in accordance with the mechanical section of the North Carolina Residential Code.

N1103.6.2 Equipment Efficiencies

AMENDMENT
This section has been amended at the state or city level.
Equipment efficiencies shall comply with the current NAECA minimum standards.

N1103.7 Snow Melt System Controls

AMENDMENT
This section has been amended at the state or city level.
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 above 50°F, and no precipitation is falling and an automatic or manual control that will allow shutoff when the outdoor temperature is above 40°F.

N1103.8 Pools, Inground Permanently Installed Spas (Mandatory)

AMENDMENT
This section has been amended at the state or city level.
Pools and inground permanently installed spas shall comply with Sections N1103.8.1 through N1103.8.3.

N1103.8.1 Pool Heaters

AMENDMENT
This section has been amended at the state or city level.

N1103.8.1 Heaters

AMENDMENT
This section has been amended at the state or city level.
All heaters shall be equipped with a readily accessible on-off switch that is mounted outside of the heater to allow shutting off the heater without adjusting the thermostat setting. Gas-fired heaters shall not be equipped with constant burning pilot lights.

N1103.8.2 Time Switches

AMENDMENT
This section has been amended at the state or city level.

Time switches or other control method that can automatically turn off and on heaters and pumps according to a preset schedule shall be installed on all heaters and pumps. Heaters, pumps and motors that have built-in timers shall be deemed in compliance with this requirement.

Exceptions:

  1. Where public health standards require 24-hour pump operation.
  2. Where pumps are required to operate solar- and waste-heat-recovery pool heating systems.

N1103.8.3 Pool Covers

AMENDMENT
This section has been amended at the state or city level.
Heated pools and inground permanently installed spas shall be provided with a vapor-retardant pool cover.

Exception: Pools deriving over 70 percent of the energy for heating from site-recovered energy, such as a heat pump or solar energy source computed over an operating season.

N1104.1 Lighting Equipment

AMENDMENT
This section has been amended at the state or city level.
A minimum of 75 percent of the lamps in permanently installed lighting fixtures shall be high-efficacy lamps.
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