The mandate that would have eliminated non-condensing furnaces by 2028 is no longer settled law. What happens next matters for every contractor, distributor, and OEM with gas furnace equipment in the portfolio.
On June 8, the U.S. Supreme Court vacated the lower court ruling that upheld the DOE's 95% AFUE efficiency mandate for residential gas furnaces and commercial water heaters. The case — American Gas Association et al. v. Department of Energy — has been sent back to the D.C. Circuit Court of Appeals for reconsideration, and the lower court's decision is no longer in effect.
This is the most significant regulatory development for the gas furnace industry in years. It also requires careful reading, because what happened is not the same as the rule being struck down.
What the Rule Would Have Done
The Biden-era DOE mandate required all new residential gas furnaces manufactured after December 18, 2028 to achieve at least 95% AFUE — a standard that only condensing furnaces can meet. Non-condensing furnaces, which make up a large portion of the installed and replacement market, would have been effectively eliminated from production. For contractors, that meant steering every customer toward condensing equipment — including customers in older homes where the venting modifications required for condensing units are costly, complicated, or simply not feasible.
The commercial water heater compliance date was even closer: October 6 of this year.
Why the Court Sent It Back
The American Gas Association argued the mandate violates the Energy Policy and Conservation Act, which prohibits the DOE from setting efficiency standards that eliminate an entire product type or class of performance characteristics. The Trump administration's Solicitor General supported that position in an April brief, and the Supreme Court agreed the lower court's decision needed to be reconsidered in light of it.
HARDI VP of Government Affairs Alex Ayers called it "a strong step toward ensuring this rule receives the scrutiny it warrants." PHCC's Chuck White was more measured: overturning the mandates entirely remains "a high bar," he said, and the best realistic outcome is the rule being returned to DOE for a new rulemaking process that properly involves contractor and industry stakeholders.
The DOE has already proposed delaying implementation while litigation continues.
What This Means Right Now
The compliance dates have not officially changed — December 2028 for furnaces, October 2026 for commercial water heaters. But the legal underpinning of those dates has just been pulled out from under them, and the current administration has signaled it views the rules as flawed and is considering revised rulemaking.
Non-condensing equipment remains legally available and the compliance picture is actively in flux. The mandate may look very different by the time any final rule takes effect.
For OEMs, the product roadmap question is live again — investments made in condensing-only manufacturing lines are not being reversed overnight, but the certainty that justified them is gone. For distributors, inventory decisions on non-condensing equipment now carry less regulatory risk than they did a month ago. For contractors, the practical guidance to customers is straightforward: the regulation is under review, condensing equipment offers real efficiency advantages where installation conditions allow, and the choice should be driven by building conditions and budget — not by a mandate that may be substantially revised before it takes effect.
Watch the D.C. Circuit. That is where this goes next.
