Administration’s fuzzy math will undermine energy efficiency savings

This story was originally published by Canary Media and is reproduced here as part of the Climate Desk collaboration.

Energy efficiency standards can make it more expensive to construct new buildings, but they save money for residents in the long run. In a new analysis, the Trump administration ignored the second half of that equation—a move that energy experts fear could undermine efficiency efforts nationwide.

Late last month, the US Department of Energy announced it found that if every state adopted the model 2024 International Energy Conservation Code (IECC) instead of following a 20-year-old building code, the move would drive up housing construction costs by $9.2 billion annually. It’s a break with decades of DOE analysis, spanning Republican and Democratic administrations, which has reported significant energy and financial savings under each iteration of the code.

“The Energy Department is completely contradicting its own findings,” said Donna Stanley, vice president of communications at the nonprofit International Code Council, which develops the model code. ​“The DOE’s new methodology is a deep mystery.”

The DOE did not respond by Monday to Canary Media’s question of why it chose to exclude energy bill savings in its analysis.

The IECC, which is updated every three years, has cut energy use in new homes in half since it was first enacted in the late 1970s. While the code is fuel-neutral, meaning that builders can install fossil-fueled equipment, it still has a positive impact for the climate because it reduces energy demand that would be met at least in part by burning fossil fuels.

Most states adopt the IECC or an amended version rather than create their own rules from scratch. Some states, like Alabama, don’t impose statewide standards. In those cases, local governments may choose to use the IECC themselves; as the city of Montgomery does, for example.

Depending on the code-adoption cycle, there can be a lag of several years before a state or local jurisdiction takes up the latest iteration of the IECC. To date, 10 states have adopted the 2024 code, per the International Code Council.

The DOE’s analysis could have a chilling effect on other states still in the process of locking in the 2024 code, including Massachusetts, Minnesota, and Ohio. Lawmakers who have sought to restrict more-efficient building codes—such as those in the Missouri House of Representatives—could use the analysis as fodder for their arguments, according to Ben Rabe, associate director of codes and policy at New Buildings Institute.

The analysis comes as the Trump administration has sought to squelch energy-efficiency efforts across the country. In 2025, it sued two California cities over their superefficient all-electric codes, and this year it has barred households from using federal home-electrification rebates to swap fossil-fueled appliances for heat-pump options. In May, the Trump DOE also rescinded a Biden-era requirement that new homes meet the 2021 IECC standard to qualify for federal mortgage loans.

The moves to crush efficiency measures could exacerbate the country’s energy-affordability problems, making people spend more at a time when electricity and fuel costs have risen fast.

The DOE has done a cost-benefit analysis of every version of the IECC, but this latest one is the first time the agency has tallied only the upfront costs from home construction and ignored the long-term bill savings, said Ted Tiffany, senior technical lead at the Building Decarbonization Coalition, a nonprofit advocacy group.

That’s like comparing cars based solely on their sticker prices while ignoring fuel costs and maintenance expenses, he added. ​“A cheaper car may cost less on Day 1, but a more efficient vehicle can save money and provide better performance, safety, and last longer over its lifetime.”

In a report for the DOE last year, the Pacific Northwest National Laboratory calculated the utility bill savings for people who move into homes built to the new standard. The 2024 model code generates an average life-cycle cost savings of nearly $3,000 per residence over the 2021 code, it estimated, though in specific regions that could rise to almost $9,500. The average payback time for a buyer paying for a home in cash, it found, is 2.5 years. Those who get a mortgage would typically see net savings on their combined home and utility payments in just one year.

The adoption of the IECC’s latest residential and commercial energy codes would save US homes and businesses $182 billion between 2010 and 2040, according to a DOE webpage that was removed shortly before the announcement.

“This is the definition of cost-effectiveness,” Tiffany said.

The DOE’s new analysis also rests on a questionable time-period comparison: It benchmarked the 2024 IECC against the 2006 version. Forty-nine states have already adopted more advanced energy codes for new residential units, according to Tiffany; they’re not building to 2006 standards. The DOE’s comparison really works only ​“for perhaps Arkansas,” he said, which lags the rest of the US in building energy codes.

The agency has estimated the added construction costs for compliance with the 2024 IECC over the 2006 IECC at $14,000 per home. 

“But we’ll save way more than that over the life of these buildings,” Rabe said.