The Energy Department disagreed with the court's ruling, telling The Hill that the "energy-saving rule only applied to heaters and furnaces and specifically excluded decorative fireplaces."
However, in a 2010 rulemaking, the court said, the Energy Department decided to "abruptly" change its proposal to regulate heaters under the National Appliance Energy Conservation Act, including both decorative fireplaces and heaters under the list of regulated products.
Following two lawsuits against the department in 2011 by the Hearth, Patio & Barbecue Association, Brown said the Obama administration then "doubled down" on its expansion of the law.
The Energy Department must now eliminate the definition of a "vented hearth heater" from the rule entirely.
This story was updated on Feb. 11 with comment and clarification from DOE.