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How to Make Your Old Windows More Energy Efficient

Written by Ryan Meres, RESNET Program Director | Oct 17, 2026, 3:37:53 PM

If installing new, energy efficient windows in your home isn’t an option, here are some ways to make your current windows more energy efficient.

Window film can improve comfort without replacing the glass. Match the film to your climate and glazing; insulating and solar-control films serve different purposes. Original GBM archive photograph.

Cold Weather Tips

  • Low-Tech. Fixing a heavy-duty, clear plastic sheet on a frame or taping a clear plastic film to the inside of your window frames will reduce drafts.
  • Film It. Choose a low-emissivity (low-e) film designed to reduce winter heat loss; a solar-control film intended mainly to block summer heat is a different choice. Have the installer confirm compatibility with your glass and window warranty before applying it.
  • Soft Cover. Consider installing tight-fitting, insulating shades on windows after weatherizing for extra sealing. Somfy’s WireFree Li-ion Solar Panel Kit (9027294) recharges compatible shade motors or battery packs; it is not a complete insulating shade. Somfy listed it at $136.95 but out of stock on October 16, 2026. AV Outlet listed it for special order at $118.95, typically shipping in five to eight business days; confirm availability and motor compatibility before buying. Motors and any separate battery pack cost extra.
  • Open and Close. Make effective use of curtains and shades by closing them at night to protect against drafts, and opening them during the day to let in warm sunlight.
  • Add Storms. Installing exterior/interior storm windows can reduce heat transfer and drafts. Low-e storm windows improve performance further; choose a product suited to your climate and existing window. Savings depend on the window, installation and home.
  • Maintain. Replace old window caulking in any storm windows you have currently installed. One easy apply option is window caulking cord, which comes in rolls. Keep drainage/weep holes open and preserve required emergency escape access.

Warm Weather Tips

  • Try using white window shades, drapes, or blinds, which will reflect heat away from the house.
  • Close curtains on south and west-facing windows during the day to block excess heat from entering the house.
  • Create shade by installing awnings on south and west-facing windows.
  • Reduce solar heat gain by applying a suitable solar-control film to sun-exposed windows. Check glass compatibility and consider the loss of useful winter solar warmth before choosing a film.

Insulating Shade Options

Two current options are Hunter Douglas Duette Honeycomb Shades, which trap air in cellular pockets and offer selected fabrics made with more than 50 percent recycled content, and LEVOLOR Custom Premium 9/16-inch Cellular Shades, which use an insulating cellular design. Duette requires a dealer consultation and custom quote. LEVOLOR’s website listed a starting price of $163.41 on October 16, 2026; dimensions, fabric, controls, tax and installation affect the final cost.

Choose cordless controls, especially where children live or visit. Owners of older shades should check the 2012 recall of certain corded Hunter Douglas shades and the 2019 recall of LEVOLOR two-corded cellular shades. These notices concern specified older configurations, not every current product.

Long Term Saving Tip

While the above tips will help make your current windows work more efficiently, for long term savings, consider replacing your windows with high-performance ones. Compare the installed cost and estimated energy savings with repairs, weatherization and storm windows; lower energy bills do not guarantee that full replacement will pay for itself.

To learn more about how to make your home energy efficient, find a certified RESNET Home Energy Rater for a home energy assessment.

This content was originally published by the Residential Energy Services Network (RESNET) here. This content has been republished with the permission of RESNET. RESNET is the independent, national nonprofit organization that homeowners trust to improve home energy efficiency and realize substantial savings on their utility bills. RESNET’s industry-leading standards are recognized by the U.S. Department of Energy and the U.S. Environmental Protection Agency, among others.

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Updated content · October 16, 2026
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