A week ago, fossil fuel companies pulled off an 11th-hour win in their fight to keep climate-friendly measures out of the next national homebuilding guidelines, successfully lobbying the private entity that writes the country’s model building codes to strip out rules that would make it cheaper for homeowners to go electric.

Democrats in Congress called the gas industry’s influence over the International Code Council’s process “a real scandal.”

Now some Republicans want to go further to prevent the U.S. from cutting back on wasted electricity and heat, even as Americans struggle to pay rising energy bills and utility debt hits record highs.

The two top House Republicans tasked with overseeing the Department of Energy are putting pressure on the agency to slow down programs meant to help states and cities adopt the new codes — which are, even after fossil fuel companies’ lobbying efforts, the most energy-efficient ones the ICC has ever written.

“We are concerned that the DOE’s building codes grant programs will exacerbate the current housing affordability crisis and limit energy choices for the American people by encouraging the adoption of such one-sized-fits-all building codes that are not appropriate or cost-effective for all income levels and regions of the country,” wrote Reps. Cathy McMorris Rodgers (R-Wash.), who chairs the House Committee on Energy and Commerce, and Jeff Duncan (R-S.C.), who leads the panel’s subcommittee on the energy grid.

Their letter is the latest sign that the wonky, highly-technical process of updating the building codes that for three decades have provided American real estate developers across the country with some degree of uniformity are being dragged into partisan culture wars.

The U.S. has no official national building code. Instead, states and cities choose which and when third-party standards to codify into law.

For example, Illinois adopts the new ICC codes when they’re released every three years — so builders in this blue state will always have to follow the greenest version of the code.

More conservative Idaho, by contrast, hasn’t updated its codes beyond the ICC’s 2009 edition, and has proposed blocking its municipalities from progressing any further.

That the Gem State is even using 15-year-old ICC codes, rather than something even more lax, is due to a rule from 2007 that affords the federal government at least some degree of leverage over states’ building codes. That statute requires federal agencies to analyze the most recent ICC codes within a year of coming out and determine whether the rules actually cut back on wasted electricity and heat and whether they’d drive up housing construction costs by too much. If the agencies sign off, the new ICC codes are supposed to be worked into eligibility requirements for federal housing loans, to make sure newly-built homes meet energy-efficiency standards.

In practice, the government has slow-walked this process. In 2015, the Obama administration made meeting the 2009 ICC codes the minimum for getting a federal housing loan, but housing loan rules haven’t been updated since. The Biden administration has signaled it would update them, but an effort to do so remains mired in the federal bureaucracy.

Seeking more carrots than sticks, President Joe Biden’s landmark climate law, the Inflation Reduction Act, earmarked over $1 billion to help regulators in states and territories enact stricter, more energy-efficient codes.

In December, the Energy Department made $530 million available for local regulators in states and territories looking for help with “the adoption and implementation of the latest model codes, zero energy codes, as well as customized codes and innovative codes that achieve equivalent energy savings to the latest model and zero energy codes.”

In their letter, addressed to Energy Secretary Jennifer Granholm, the GOP lawmakers accused the agency of failing to clearly define what any of those words meant.

The four-page letter presses Granholm on seemingly unrelated points, like whether the administration would support codes that ban electricity derived from nuclear power plants.

To the contrary, atomic power is a top source of zero-carbon electricity that the Biden administration has heavily subsidized, including an unprecedented $1.5 billion loan announced this week to reopen the country’s most recently-closed nuclear plant in Michigan.

The letter also misleadingly characterizes the effects of updating to stricter codes, which apply to newer construction and are designed to help avoid costly renovations later.

“State and local governments should not be forced to adopt international energy codes that set efficiency requirements, ban the use of natural gas, or require expensive electrification retrofits for appliances and electric vehicle charging,” the lawmakers wrote.

But the whole point of raising the standards on new buildings in the first place is to help future homeowners avoid costly retrofits down the road.

The building codes the ICC stripped from its latest codebook this month would have required developers to wire new homes and commercial buildings with the circuitry for electric appliances, heat pumps and car chargers. Federal research shows that rewiring an already-built wall to install a heat pump costs upward of $2,100, compared to just $500 to include the circuitry during construction.

Roughly 90% of experts who participated in the ICC’s latest code-writing process supported the pro-electrification rules. But trade associations representing gas utilities and furnace manufacturers challenged the provisions last fall, filing last-minute appeals. The ICC’s appeals board rejected all the appeals this month. But the ICC’s board of directors overruled its own staff to grant the gas companies’ request last week.

The change is already having an effect. New York was poised to adopt the latest codes last week. Surprised by the ICC’s ruling, the state postponed the regulatory process by three months.