The U.S. Department of Energy (“DOE”) has promulgated regulations that appear to subject essentially all vented gas fireplaces—including decorative gas fireplaces certified to the American National Standards Institute (“ANSI”) Z21.50 standard—to heating efficiency standards, 75 Fed. Reg. 20112 (April 16, 2010). The Hearth, Patio & Barbecue Association (“HPBA”) believes that this final rule was ill-considered and unlawful in a number of respects.