Sealing and insulating the "envelope" or "shell" of your home . EPA estimates that homeowners can typically save up to 20% of heating and cooling costs (or up to 10% of total energy costs) by air sealing their homes and adding insulation in attics, floors over crawl spaces, and accessible basement rim joists. This estimate is based on energy modeling (using REM/Rate version 11.0) of cost-effective improvements made to 'typical' existing U.S. homes with a weighted composite of characteristics. The modeled results are corroborated by the field experience of professional building science contractors who have done air sealing and insulation work for more than 20 years.
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