U-factor measures the heat transfer through a window and tells you how well the product insulates. The lower the U-factor, the greater resistance to heat flow (in and out) and the better its insulation value. ENERGY STAR window U-factor values generally range from less than or equal to 0.27 up to 0.40 depending on the climate zone. The top performing ENERGY STAR Most Efficient windows have U-factors of less than or equal to 0.20.
energy efficient products
ENERGY STAR products are independently certified to save energy without sacrificing features or functionality. Saving energy helps prevent climate change. Look for the ENERGY STAR label to save money on your energy bills and help protect our environment.
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ENERGY SAVINGSat home
energy savings at home
Improving your home's energy efficiency with ENERGY STAR can help to lower high energy bills, improve comfort and reduce greenhouse gas emissions. Learn about the many ways to save in your home and track your progress with "My ENERGY STAR" - your new dashboard to savings.
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ENERGY EFFICIENTnew homes
energy efficient new homes
A new home that has earned the ENERGY STAR label has undergone a process of inspections, testing, and verification to meet strict requirements set by the US EPA. ENERGY STAR certified homes use 15-30% less energy than typical new homes while delivering better comfort, quality, and durability.
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ENERGY STRATEGIES FORbuildings & plants