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2009 and 2012 IECC Code Level Insulation – ENERGY STAR Requirements

Scope

Identify what materials will constitute the continuous air barrier around the building envelope.
Identify what materials will constitute the continuous air barrier around the building envelope.

Install ceiling, wall, and foundation insulation that meets or exceeds the requirements of the most recent International Energy Conservation Code adopted by your state or municipality.

See the Compliance Tab for related codes and standards requirements, and specific criteria to meet ENERGY STAR Certified Homes and DOE’s Zero Energy Ready Home program.

Description

ENERGY STAR Certified Homes Version 3.0, Revision 09 - for States that Have Adopted the 2009 IECC

For builders who wish to certify their homes to the ENERGY STAR Certified Homes program (Version 3.0, Rev 09), the ENERGY STAR National Program Requirements and Rater Design Review Checklist, Item 3.1, specify that the home's ceiling, wall, floor, and slab insulation levels must comply with one of the following options:

3.1.1 Meet or exceed 2009 IECC levels OR

3.1.2  Achieve ≤ 133% of the total UA resulting from the U-factors in 2009 IECC Table 402.1.3, and meet the following infiltration limits:

  • 3 ACH50 in CZs 1,2 
  • 2.5 ACH 50 in CZs 3,4 
  • 2 ACH 50 in CZs 5,6,7
  • 1.5 ACH 50 in CZ 8

Details and exceptions for these options are described in the Compliance tab.

In addition to these requirements, ENERGY STAR (Version 3/3.1, Rev 09) requires that insulation be installed to RESNET Grade 1 quality as described in the guide Insulation Installation (RESNET Grade 1). ENERGY STAR requires that the insulation be fully aligned with (in continuous contact with) a complete air barrier and that thermal bridging be reduced and building assemblies be properly air sealed as described in the ENERGY STAR Rater Field Checklist.

ENERGY STAR Certified Homes Version 3.1, Revision 09 - for States that Have Adopted the 2012, 2015, or 2018 IECC

States that have adopted the 2012, 2015, or 2018 IECC, or an equivalent code, should follow the requirements of ENERGY STAR Version 3.1, which requires the higher insulation levels found in the 2012 IECC. Note that regional program requirements, and associated implementation timelines, have been developed for homes in CA, FL, GU, HI, the Northern Mariana Islands, OR, PR, and WA. The National Version 3.1 and regional program requirements can be found at ENERGY STAR's Residential New Construction Program Requirements web page.

Visit the U.S. DOE Building Energy Codes Program website to see what code has been adopted in your state.

Ensuring Success

For Option 3.1.1, consult the insulation requirements of the 2009 or 2012 International Energy Conservation Code (IECC) to ensure the R-value requirements are met or exceeded. Also review the exceptions that ENERGY STAR provides for ceilings as these can affect the required insulation levels.

Option 3.1.2 relaxes overall insulation requirements for the ceiling, walls, and foundation components if specified infiltration rates are met.

Climate

Climate-specific requirements as specified in the IECC are shown in Table 1 on the Compliance Tab of this guide. 

IECC Climate Zone Map
IECC Climate Zone Map 

Training

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Presentations

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Compliance

The Compliance tab contains both program and code information. Code language is excerpted and summarized below. For exact code language, refer to the applicable code, which may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.

ENERGY STAR Certified Homes (Version 3.0, Revision 09)

States that have adopted IECC 2012, 2015, or 2018 must meet the requirements of ENERGY STAR Version 3.1, which specifies that homes meet or exceed 2012 IECC insulation levels. Regional program requirements, and associated implementation timelines, have been developed for homes in CA, FL, GU, HI, the Northern Mariana Islands, OR, PR, and WA. The National Version 3.1 and regional program requirements can be found at ENERGY STAR's Residential New Construction Program Requirements web page.

Rater Design Review Checklist

3. High-Performance Insulation.
3.1 Specified ceiling, wall, floor, and slab insulation levels comply with one of the following options:
3.1.1 Meets or exceeds 2009 IECC levels4, 5, 6 OR;
3.1.2 Achieves ≤ 133% of the total UA resulting from the U-factors in 2009 IECC Table 402.1.3, per guidance in Footnote 4d, AND specified home infiltration does not exceed the following:5, 6

  • 3 ACH50 in CZs 1, 2
  • 2.5 ACH50 in CZs 3, 4
  • 2 ACH50 in CZs 5, 6, 7
  • 1.5 ACH50 in CZ 8

Footnote 4) Specified levels shall meet or exceed the component insulation levels in 2009 IECC Table 402.1.1. The following exceptions apply:
a. Steel-frame ceilings, walls, and floors shall meet the insulation levels of 2009 IECC Table 402.2.5. In CZ 1 and 2, the continuous insulation requirements in this table shall be permitted to be reduced to R-3 for steel-frame wall assemblies with studs spaced at 24 in. on center. This exception shall not apply if the alternative calculations in d) are used;
b. For ceilings with attic spaces, R-30 shall satisfy the requirement for R-38 and R-38 shall satisfy the requirement for R-49 wherever the full height of uncompressed insulation at the lower R-value extends over the wall top plate at the eaves. This exemption shall not apply if the alternative calculations in d) are used;
c. For ceilings without attic spaces, R-30 shall satisfy the requirement for any required value above R-30 if the design of the roof / ceiling assembly does not provide sufficient space for the required insulation value. This exemption shall be limited to 500 sq. ft. or 20% of the total insulated ceiling area, whichever is less. This exemption shall not apply if the alternative calculations in d) are used;
d. An alternative equivalent U-factor or total UA calculation may also be used to demonstrate compliance, as follows: An assembly with a U-factor equal or less than specified in 2009 IECC Table 402.1.3 complies. A total building thermal envelope UA that is less than or equal to the total UA resulting from the U-factors in Table 402.1.3 also complies. The performance of all components (i.e., ceilings, walls, floors, slabs, and fenestration) can be traded off using the UA approach. Note that Items 3.1 through 3.3 of the National Rater Field Checklist shall be met regardless of the UA tradeoffs calculated. 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 calculation for a steel-frame envelope assembly shall use the ASHRAE zone method or a method providing equivalent results, and not a series-parallel path calculation method.

Footnote 5) Consistent with the 2009 IECC, slab edge insulation is only required for slab-on-grade floors with a floor surface less than 12 inches below grade. Slab insulation shall extend to the top of the slab to provide a complete thermal break. If the top edge of the insulation is installed between the exterior wall and the edge of the interior slab, it shall be permitted to be cut at a 45-degree angle away from the exterior wall. Alternatively, the thermal break is permitted to be created using ≥ R-3 rigid insulation on top of an existing slab (e.g., in a home undergoing a gut rehabilitation). In such cases, up to 10% of the slab surface is permitted to not be insulated (e.g., for sleepers, for sill plates). Insulation installed on top of slab shall be covered by a durable floor surface (e.g., hardwood, tile, carpet).

Footnote 6) Where an insulated wall separates a garage, patio, porch, or other unconditioned space from the conditioned space of the house, slab insulation shall also be installed at this interface to provide a thermal break between the conditioned and unconditioned slab. Where specific details cannot meet this requirement, partners shall provide the detail to EPA to request an exemption prior to the home’s certification. EPA will compile exempted details and work with industry to develop feasible details for use in future revisions to the program. A list of currently exempted details is available at: energystar.gov/slabedge.

Rater Field Checklist

Thermal Enclosure System
1. High-Performance Fenestration & Insulation.
1.2 Insulation meets or exceeds specification in Item 3.1 of the National Rater Design Review Checklist.
1.3 All insulation achieves Grade I install. per ANSI / RESNET / ICC Std. 301. Alternatives in Footnote 4.4, 5

Footnote 4) Two alternatives are provided: a) Grade II cavity insulation is permitted to be used for assemblies that contain a layer of continuous, air impermeable insulation ≥ R-3 in Climate Zones 1 to 4, ≥ R-5 in Climate Zones 5 to 8; b) Grade II batts are permitted to be used in floors if they fill the full depth of the floor cavity, even when compression occurs due to excess insulation, as long as the R-value of the batts has been appropriately assessed based on manufacturer guidance and the only defect preventing the insulation from achieving Grade I is the compression caused by the excess insulation.

Foontote 5) Ensure compliance with this requirement using the version of ANSI / RESNET / ICC Std. 301 utilized by RESNET for HERS ratings. 

Please see the ENERGY STAR Certified Homes Implementation Timeline for the program version and revision currently applicable in in your state.

DOE Zero Energy Ready Home Program (Revision 07)

Exhibit 1 Mandatory Requirements.
Exhibit 1, Item 1) Certified under the ENERGY STAR Qualified Homes Program or the ENERGY STAR Multifamily New Construction Program.
Exhibit 2, Item 2) Ceiling, wall, floor, and slab insulation shall meet or exceed 2015 IECC levels and achieve Grade 1 installation, per RESNET standards.

Footnote 12) Building envelope assemblies, including exterior walls and unvented attic assemblies (where used), shall comply with the relevant vapor retarder provisions of the 2015 International Residential Code (IRC).

Footnote 13) Insulation levels in a home shall meet or exceed the component insulation requirements in the 2015 International Energy Conservation Code (IECC) - Table R402.1.2. The following exceptions apply:

a. Steel-frame ceilings, walls, and floors shall meet the insulation requirements of the 2015 IECC – Table 402.2.6.

b. For ceilings with attic spaces, R-30 shall satisfy the requirement for R-38 and R-38 shall satisfy the requirement for R-49 wherever the full height of uncompressed insulation at the lower R-value extends over the wall top plate at the eaves. This exemption shall not apply if the alternative calculations in d) are used;

c. For ceilings without attic spaces, R-30 shall satisfy the requirement for any required value above R-30 if the design of the roof / ceiling assembly does not provide sufficient space for the required insulation value. This exemption shall be limited to 500 sq. ft. or 20% of the total insulated ceiling area, whichever is less. This exemption shall not apply if the alternative calculations in d) are used;

d. An alternative equivalent U-factor or total UA calculation may also be used to demonstrate compliance, as follows: An assembly with a U-factor equal or less than specified in 2015 IECC Table 402.1.4 complies. A total building thermal envelope UA that is less than or equal to the total UA resulting from the U-factors in Table 402.1.4 also complies. The insulation levels of fenestration, ceilings, walls, floors, and slabs can be traded off using the UA approach under both the Prescriptive and the Performance Path. Also, note that while ceiling and slab insulation can be included in trade-off calculations, Items 3.1 through 3.3 of the ENERGY STAR Rev 09 Rater Field Checklist shall be met regardless of the UA tradeoffs calculated. 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 calculation for a steel-frame envelope assembly shall use the ASHRAE zone method or a method providing equivalent results, and not a series-parallel path calculation method.

DOE Zero Energy Ready Home National Program Requirements Revision 07 are required for homes permitted starting 06/01/2019. Homes started before 06/01/2019 but on or after 07/20/2017 may use either the Revision 06 or Revision 07 requirements.

2009 IECC

Building thermal envelope components to meet or exceed the values in Table 402.1.1Insulation and Fenestration Requirements By Component. Section 402.2.1 Ceilings with attic spaces, R-30 satisfies the requirement for R-38 in the ceiling wherever insulation achieves its full height over the wall top plate at the eaves and is uncompressed. Similarly, R-38 can satisfy an R-49 wherever insulation achieves its full height over the wall top plate at the eaves and is uncompressed. Section 402.2.2 Ceilings without attic spaces, R-30 satisfies the requirement for any required value above R-30 if the design of the roof/ceiling assembly does not provide sufficient space for the required insulation value. This exemption is limited to 500 sq. ft. or 20% of the total insulated ceiling area, whichever is less. Section 402.2.8 Slab-on-grade floors, slabs less than 12 inches below grade to be insulated per Table 402.1.1 with insulation extending downward from top of the slab on inside or outside of the foundation wall. Below-grade insulation to extend the distance in Table 402.1.1. Insulation extending away from the building to be protected by pavement or at least 10 inches of soil. The top insulation edge may be cut at a 45-degree angle away from the exterior wall. Slab insulation isn’t required in areas of very heavy termite infestation, with approval of code official.

2012 IECC

Building thermal envelope components to meet or exceed the values in Table R402.1.1Insulation and Fenestration Requirements By Component. Section R402.2.1 Ceilings with attic spaces, R-30 satisfies the requirement for R-38 in the ceiling wherever insulation achieves its full height over the wall top plate at the eaves and is uncompressed. Similarly, R-38 can satisfy an R-49 wherever insulation achieves its full height over the wall top plate at the eaves and is uncompressed. Section R402.2.2 Ceilings without attic spaces, R-30 satisfies the requirement for any required value above R-30 if the design of the roof/ceiling assembly does not provide sufficient space for the required insulation value. This exemption is limited to 500 sq. ft. or 20% of the total insulated ceiling area, whichever is less. Section R402.2.9 Slab-on-grade floors, slabs less than 12 inches below grade to be insulated per Table 402.1.1 with insulation extending downward from top of the slab on inside or outside of the foundation wall. Below-grade insulation to extend the distance in Table 402.1.1. Insulation extending away from the building to be protected by pavement or at least 10 inches of soil. The top insulation edge may be cut at a 45-degree angle away from the exterior wall. Slab insulation isn’t required in areas of very heavy termite infestation, with approval of code official.

2015 IECC and 2018 IECC

Building thermal envelope components to meet or exceed the values in Table R402.1.1, Insulation and Fenestration Requirements by Component. Follow specific insulation requirements in Section R402.2.

200920122015, and 2018 IECC / 200920122015, and 2018 IRC

The minimum insulation requirements for ceilings, walls, floors, and foundations in new homes, as listed in the 2009, 2012, 2015, and 2018 IECC and IRC, can be found in Table 1. 

Minimum Insulation Requirements for New Homes as Listed in the 2009, 2012, 2015, and 2018 IECC and 2009, 2012, 2015, and 2018 IRC.

 

Retrofit: 2009, 2012, 2015, and 2018 IECC

Section R101.4.3 (Section R501.1.1 in 2015 and 2018 IECC). Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with this code. (See code for additional requirements and exceptions.)

2009 IRC, 2012 IRC, 2015 IRC, and 2018 IRC

For IRC 2009-18 insulation requirements, see Table 1 above. Insulation requirements are described in Chapter 11 Energy Efficiency. Water management details are descried in R405 Foundation Drainage and R406 Foundation Waterproofing and Dampproofing.

Retrofit: 2009, 2012, 2015, and 2018 IRC

Section N1101.3 (Section N1107.1.1 in 2015 and 2018 IRC). Additions, alterations, renovations, or repairs shall conform to the provisions of this code, without requiring the unaltered portions of the existing building to comply with this code. (See code for additional requirements and exceptions.)

Appendix J regulates the repair, renovation, alteration, and reconstruction of existing buildings and is intended to encourage their continued safe use.

More Info.

Access to some references may require purchase from the publisher. While we continually update our database, links may have changed since posting. Please contact our webmaster if you find broken links.

Case Studies

  1. Author(s): PNNL
    Organization(s): PNNL
    Publication Date: January, 2013

    Case study about the first certified DOE Zero Energy Ready Home—the “Wilson Residence” in Winter Park, Florida.

  2. Author(s): PNNL
    Organization(s): PNNL
    Publication Date: January, 2013

    Case study of a DOE Challenge Home in Winter Park FL that scored HERS 57 without PV or HERS -7 with PV. This 4,305 ft2 custom home has autoclaved aerated concrete walls, a sealed attic with R-20 spray foam, and ductless mini-split heat pumps.

References and Resources*

  1. Author(s): International Code Council
    Organization(s): ICC
    Publication Date: January, 2009

    Code establishing a baseline for energy efficiency by setting performance standards for the building envelope (defined as the boundary that separates heated/cooled air from unconditioned, outside air), mechanical systems, lighting systems and service water heating systems in homes and commercial businesses.

  2. Author(s): Baechler, Adams, Hefty, Gilbride, Love
    Organization(s): Pacific Northwest National Laboratory, Oak Ridge National Laboratory
    Publication Date: May, 2012

    Guide to help contractors and homeowners identify ways to make homes more comfortable, more energy efficient, and healthier to live in.

  3. Author(s): U.S. Department of Energy
    Organization(s): DOE
    Publication Date: May, 2019

    Standard requirements for DOE's Zero Energy Ready Home national program certification.

  4. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: September, 2018

    Webpage with links to documents providing the program requirements and checklists for ENERGY STAR Certified Homes (Ver. 3/3.1, Rev. 09).

  5. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: October, 2011

    Guide describing details that serve as a visual reference for each of the line items in the Thermal Enclosure System Rater Checklist.

Contributors to this Guide

The following authors and organizations contributed to the content in this Guide.

Last Updated: 07/16/2019