DOE analysis finds the 2018 IECC increases energy efficiency
The Office of Energy Efficiency and Renewable Energy of the U.S. Department of Energy (DOE) issued its final determination regarding energy efficiency improvements in the 2018 International Energy Conservation Code (IECC). The determination states that the 2018 IECC would improve energy efficiency in buildings subject to the code compared to the 2015 edition.
The DOE analysis indicates that buildings meeting the 2018 IECC (as compared with buildings meeting the 2015 IECC) would result in national site energy savings of 1.68 percent, national source energy savings of 1.91 percent, and national energy cost savings of approximately 1.97 percent of residential building energy consumption. These changes are expected to have a significant and measurable impact on energy efficiency in residential buildings because they increase energy savings and impact a significant fraction of new homes.
The DOE reviewed the 2018 IECC to identify changes that have a direct impact on energy efficiency, and which could be reasonably quantified in estimating national average savings impacts. In total, 47 individual changes were identified. A more detailed discussion may be found in the final energy savings analysis.
In its preliminary analysis, the DOE identified two key changes that compose the bulk of the energy savings associated with the updated code: RE31 (Fenestration) that lowers (improves) fenestration U-factors and RE127 (Lighting) that increases high-efficacy lighting from 75 percent to 90 percent of permanently installed fixtures in all homes. Together, the key impacts identified above are expected to result in life-cycle cost savings ranging from a low of $398 to a high of $1071. National average savings are $480 with a payback of 1.1 years.
A copy of the final analysis is available here.