2009 and 2012 IECC Code Level Insulation – ENERGY STAR Requirements

    Scope

    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 videos Insulation Installation (RESNET Grade 1) - Part 1 and Insulation Installation (RESNET Grade 1) - Part 2. 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-Design Review Checklist: 3. High-Performance Insulation.

    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.

    Typical R-values for common insulation materials are summarized in this table, which also identifies the vapor retarder classification for each insulation.

    Climate

    The map in Figure 1 shows the climate zones for states that have adopted energy codes equivalent to the International Energy Conservation Code (IECC) 2009, 12, 15, and 18. The map in Figure 2 shows the climate zones for states that have adopted energy codes equivalent to the IECC 2021. Climate zone-specific requirements specified in the IECC are shown in the Compliance Tab of this guide. 

    Figure 1. Climate Zone Map from IECC 2009, 12, 15, and 18.
    Figure 1. Climate Zone Map from IECC 2009, 12, 15, and 18 (Source: 2012 IECC). 
    Climate Zone Map from IECC 2021.
    Figure 2. Climate Zone Map from IECC 2021 (Source: 2021 IECC).

     

    Right and Wrong Images
    Image
    Right – RESNET grade I installation of batt insulation
    Right – RESNET grade I installation of batt insulation
    Image
    Right - Batt was properly split around wires to achieve RESNET Grade I
    Right - Batt was properly split around wires to achieve RESNET Grade I
    Image
    Right – RESNET Grade I installation of blown insulation
    Right – RESNET Grade I installation of blown insulation

    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.

    Footnote 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.

     

    2009-2021 IECC and IRC Insulation Requirements Table

    The minimum insulation requirements for ceilings, walls, floors, and foundations in new homes, as listed in the 2009, 2012, 2015, 2018, and 2021 IECC and IRC, can be found in this table

     

    2009, 2012, 2015, 2018,  and 2021 International Energy Conservation Code (IECC)

    Building thermal envelope components to meet or exceed the values in Table R402.1.3 (R402.1.2 in 2015 and 2018, 402.1.1 in 2012 and 2009 IECC) Insulation 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. In the 2021 IECC, this exception is extended: R-49 can satisfy R-60 requirements where the full height of uncompressed R-49 insulation extends over the wall top plate at the eaves.

    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 402.2.9.1 (R402.2.10 in 2015 and 2018, R402.2.9 in 2012, and 402.2.8 in 2009 IECC) Slab-on-grade floors, slabs less than 12 inches below grade to be insulated per Table 402.1.3 (or respective table) 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 402.1.3 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.

    Retrofit:   2009, 2012, 2015, 2018,  and 2021 IECC

    Section R101.4.3 (in 2009 and 2012). 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.)

    Chapter 5 (in 2015, 2018, 2021). The provisions of this chapter shall control the alteration, repair, addition, and change of occupancy of existing buildings and structures.

    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
    Author(s)
    Pacific Northwest National Laboratory,
    U.S. Department of Energy
    Organization(s)
    PNNL,
    DOE
    Publication Date
    Description
    Case study describing a DOE Zero Energy Ready Home 2013 Housing Innovation Award Winner in Winter Park FL that scored HERS 57 without PV or HERS -7 with PV.
    References and Resources*
    Author(s)
    U.S. Environmental Protection Agency
    Organization(s)
    EPA
    Publication Date
    Description
    Guide describing details that serve as a visual reference for each of the line items in the Thermal Enclosure System Rater Checklist.
    *For non-dated media, such as websites, the date listed is the date accessed.
    Contributors to this Guide

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

    Building Science Measures
    Building Science-to-Sales Translator

    High-R Insulation = High-Efficiency or Ultra-Efficient Insulation

    Image(s)
    Technical Description

    There are two levels of insulation: high-efficiency insulation, which meets the 2015 International Energy Conservation Code, and ultra-efficient insulation, which is 25% more efficient than this national code. Using high-efficiency and ultra-efficient insulation along with professional installation (e.g., no gaps, voids, compression, or misalignment with air barriers; complete air barriers; and minimal thermal bridging) creates conditioned spaces that require very little heating and cooling, along with, even comfort and quiet throughout the house.

    High-Efficiency or Ultra-Efficient Insulation
    Sales Message

    High-efficiency insulation helps provide added thermal protection. What this means to you is less wasted energy along with enhanced comfort and quiet. Knowing there is only one opportunity during construction to lock in your home’s thermal protection, wouldn’t you agree high-efficiency insulation that meets or exceeds future codes is a great investment?

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