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
Leading Suppliers Council
Dec 24, 2025
10 Ways to Turn Your Business Into a Lean, Mean Building MachineMyriad industry challenges are adding time and cost to home building projects. But with the right technology, you can better anticipate and manage those challenges to help optimize your business' performance and profits.
Sponsored Content
Dec 23, 2025
The 5 Types of Builders — and the One Built to ProsperMost builders want the same things: predictable profits, less stress, and a business that doesn’t grind them down year after year.
Latest Economic News
Economics
Dec 22, 2025
State-Level Employment Situation: September 2025In September 2025, nonfarm payroll employment was largely unchanged across states on a monthly basis, with a limited number of states seeing statistically significant increases or decreases. This reflects generally stable job counts across states despite broader labor market fluctuations. The data were impacted by collection delays due to the federal government shutdown.
Economics
Dec 19, 2025
Existing Home Sales Edge Higher in NovemberExisting home sales rose for the third consecutive month in November as lower mortgage rates continued to boost home sales, according to the National Association of Realtors (NAR). However, the increase remained modest as mortgage rates still stayed above 6% while down from recent highs. The weakening job market also weighed on buyer activity.
Economics
Dec 18, 2025
Lumber Capacity Lower Midway Through 2025Sawmill production has remained essentially flat over the past two years, according to the Federal Reserve G.17 Industrial Production report. This most recent data release contained an annual revision, which resulted in higher estimates for both production and capacity in U.S. sawmills.