This bill, known as the Federal Mechanical Insulation Act of 2026, amends the National Energy Conservation Policy Act to explicitly recognize the installation of mechanical insulation property as an energy or water efficiency measure. It defines this property as insulation material, facing, or accessory products used in connection with a mechanical system. These materials must meet or exceed the minimum requirements of ASHRAE Standard 90.1 and result in a reduction in energy loss from the mechanical system. The legislation further mandates that comprehensive energy and water evaluations for federal buildings must now include the identification of energy- and water-saving measures, specifically mentioning the installation of mechanical insulation property. This aims to promote greater energy and water efficiency within federal facilities by incorporating these specific insulation solutions into energy conservation strategies.