Department of Energy: New Model Residential Energy Code Includes Increases in Efficiency Requirements
The Department of Energy (DOE) today issued a positive determination that the 2021 International Energy Conservation Code (IECC) contains new requirements that result in an incremental increase in energy efficiency in residential buildings.
The IECC is part of a family of model building codes published by the International Code Council (ICC) and adopted in many jurisdictions around the country, often with specific amendments based on local market and climatic conditions.
DOE reports it came to this conclusion by conducting a technical analysis evaluating the impacts of the updated code relative to the 2018 IECC edition.
DOE estimates national savings of approximately:
- 9.38% site energy savings
- 8.79% source energy savings
- 8.66% energy cost savings
- 8.66% carbon emissions
DOE is required by law to issue a determination as to whether the latest version of the IECC includes increases in energy efficiency compared to the previous edition of the code. DOE has one year to publish a determination in the Federal Register after each new edition of the standard/code is published.
States will now be required to certify that they have reviewed the provisions of their residential building code regarding energy efficiency, and made a determination as to whether it is appropriate for them to revise their code to meet or exceed the updated edition of the IECC.State certifications for the 2021 IECC must be submitted by July 21, 2023.
DOE’s determination is consistent with the analysis released by Home Innovation Research Labs last month that showed similar increases in efficiency. The Home Innovation report also contains the associated cost and cost-effectiveness metrics for the changes in efficiency requirements in the 2021 IECC.
Latest from NAHBNow
Oct 23, 2025
IBS 2026 Exhibit Home Aims for Groundbreaking Energy-Efficiency RatingFor anyone curious about how far today’s innovative building products can take a home’s performance, The New American Home 2026 is the must-see showcase at the upcoming Builders’ Show, taking place Feb. 17–19.
Oct 22, 2025
NAHB Generates Enthusiasm for the Trades During the Big BuildNAHB recently introduced thousands of students to the skilled trades during The Big Build event at the National Building Museum in Washington, D.C.
Latest Economic News
Oct 20, 2025
Non-Conventional Financing for New Home Sales Loses Ground in 2024Nationwide, the share of non-conventional financing for new home sales accounted for 31% of the market per NAHB analysis of the 2024 Census Bureau Survey of Construction (SOC) data. This is 1.7 percentage point lower than the 2023 share of 32.4%. As in previous years, conventional financing dominated the market at 69.3% of sales, higher than the 2023 share of 67.6%.
Oct 17, 2025
Better Growth, Larger Deficits: CBO Fiscal OutlookThe Congressional Budget Office (CBO) is a key nonpartisan score keeper that measures the effects of policy changes by the Federal Government. With several policy changes since January of this year, including the One Big Beautiful Bill Act (OBBBA), stricter immigration, and higher tariffs, the CBO updated its economic projections through 2028.
Oct 16, 2025
Amid Market Challenges, Builder Expectations Rise in OctoberEven as builders continue to grapple with market and macroeconomic uncertainty, sentiment levels posted a solid gain in October as future sales expectations surpassed the 50-point breakeven mark for the first time since last January.