US HB3474

Amends Section 543(f) of the National Energy Conservation Policy Act to add a definition of "mechanical insulation property" as insulation materials, facings, and accessory products used with mechanical systems

Requires mechanical insulation installations to meet or exceed ASHRAE Standard 90.1 minimum requirements and result in reduced energy loss from mechanical systems

Mandates that comprehensive energy and water evaluations of federal buildings include identification of mechanical insulation property installation as a potential energy and water-saving measure

Bipartisan legislation introduced May 15, 2025 by Rep. Weber (R-TX) and Rep. Sánchez (D-CA), with 35 additional cosponsors from both parties