Consumers completely replace their existing primary windows when installing ENERGY STAR certified primary windows.
#ACRYLIC INTERIOR STORM WINDOWS R VALUE FULL#
On the other hand, ENERGY STAR certified primary windows have a full frame and at least two layers of glass, which may also have low-e coatings. Exterior storm windows are installed on the outside of your primary windows, and interior storm windows are installed on the inside of your primary windows.
#ACRYLIC INTERIOR STORM WINDOWS R VALUE VERIFICATION#
ENERGY STAR certified storm windows are tested and certified to meet the program requirements and are subject to additional routine performance verification testing. Why are ENERGY STAR certified storm windows better than other storm windows? The ENERGY STAR label makes it easy to select low-e storm windows that are designed to deliver cost-effective energy savings in your area.Some types of durable plastic storm windows may also have low-e characteristics. Some low-e glass also has a low solar transmittance (Tsol) rating that blocks heat coming in from the outside and can help to keep your house cooler in the summer, saving on air conditioning bills. What is a “low-e” storm window? A storm window with low-e glass has a microscopically thin, almost invisible, durable coating that reduces heat loss through the window glass when it is cold outside, saving on heating bills.What should you consider when purchasing storm windows?īefore purchasing storm windows, consider these questions: Use the PRODUCT FINDER link above (on the right) to find the full list of ENERGY STAR certified storm windows. Actual homeowner savings will depend on local climate, individual home characteristics, and local utility rates.Ĭonsumers who already have clear glass storm windows over their single pane windows and replace the storms with ENERGY STAR certified (low-e) storm windows can save an additional $50 per year on heating and cooling (about 2%) on a national average.Įarning the ENERGY STAR label means products meet strict energy efficiency guidelines set by the U.S. These estimates are conservative and do not include savings from reducing air leaks from older windows, which provides additional savings but can vary substantially from house to house. Consumers can expect to pay back the incremental cost of the ENERGY STAR certified storm windows in about three (3) years. EPA estimates that on a national average, ENERGY STAR certified (low-e) storm windows can save homeowners $350 on their annual heating and cooling bills (about 10%) when installed over single-pane clear glass windows (without existing storm windows).