Windows installed in unconditioned basements, including hopper and glass block windows, are eligible for Program incentives and should be modeled as air sealing. Replacing broken, leaky, or deteriorated basement windows can significantly reduce a home’s air infiltration.
Windows installed in a conditioned, intentionally heated basement should be modeled as a window and must meet the Federal ENERGY STAR standards for the relevant climate zone. You can model an air sealing reduction to capture those savings, but the window cost cannot be submitted as air sealing. Windows installed in conditioned space are eligible for financing only and subject to the loan cost effectiveness requirements.
Please remember that SHPO approval may be required on homes over 50 years old prior to install. If you are using a subcontractor, that must be identified on the workscope for the homeowner and a copy provided to the Program.