The U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy recently issued a preliminary analysis of the 2021 International Energy Conservation Code (IECC), noting that the code will improve energy efficiency in residential buildings. DOE’s technical analysis of the updated code (relative to the 2018 IECC edition) pegs national savings of approximately:  

• 9.38 percent site energy savings
• 8.70 percent source energy savings
• 8.66 percent energy cost savings
• 8.66 percent carbon emissions reduction

DOE also published its technical analysis document which details the 114 code change proposals that were identified and analyzed for the 2021 IECC. That analysis revealed 35 changes with a direct impact on energy use in residential buildings – 29 of these expected to reduce energy use and 6 expected to increase energy use. Additionally, there were 79 changes that were analyzed that will have no direct impact on energy savings. 

With each edition of the IECC, DOE is required by statute to issue a determination as to whether the updated edition will improve energy efficiency in residential buildings 

(42 U.S.C. 6833.)

Why it Matters

The International Code Council (ICC) develops a set of model codes for states and municipalities to model their local building codes after. Recent editions of the IECC saw marginal improvements to the code, with the 2018 IECC seeing only a 1.68 percent savings in annual site energy compared to the 2015 IECC and the 2015 IECC seeing only 0.98 percent savings in annual site energy compared to the 2012 IECC. The 2021 IECC is a big step forward in energy efficiency and will be an important tool to help states meet their climate goals by cutting energy use in buildings.