The rule will effectively ban the sale of non-condensing gas furnaces and, according to the American Gas Association (AGA), will affect 55% of U.S. households.

The U.S. District Court of Appeals for the Ninth Circuit recently turned down the city of Berkeley’s request for another hearing in the case brought by the California Restaurant Association (CRA), which had challenged the ban.

The final rule from the U.S. Department of Energy, issued recently, requires newly manufactured indoor residential gas furnaces to be at least 95% efficient starting in December 2028, meaning furnaces made after then will have to be condensing models.

The change comes as the industry anticipates accelerated adoption of CO₂ refrigeration technology being driven by food retail businesses pledging sustainability targets and needing to comply with environmental regulations.

Court filings by Associated Builders and Contractors and its Southeast Texas chapter, in U.S. District Court for the Eastern District of Texas, were announced Nov. 7.

Manufacturers will have five years, from the date the rule is published in the Federal Register, to ensure that new gas furnaces comply with the new minimum.