Reducing window heat loss


Windows lose a considerable amount of heat every day – up to 10 times as much as walls. Heat is lost through the glass, wood and framing materials, as well as from air leakage around window frames.

Tips to reduce heat loss from windows

Here are some ideas to improve the insulating value of your windows:

  • Hang heavy drapes to reduce winter heat loss, especially at night.
  • Install storm windows or add shrink-wrap plastic to the interior of windows to create additional layers of glazing.
  • Caulk and weather-strip your windows to reduce drafts and keep heat in. See air sealing for more information.

Replace your windows

Replacing aging windows can make a huge impact on the energy efficiency and comfort level of your home. New advanced technologies and designs have dramatically improved the efficiencies of windows using glass coating, gas fills, warm edge spacers and improved framing materials.

Benefits of new windows:

  • Cut down your energy costs.
  • Increase the comfort of your home.
  • Allow for higher humidity in your home.
  • Easy to maintain.

Buying tips

Look for windows with:

  • Energy rating (ER) of -11, or better.
  • Low-emissivity (low-e) glass and inert gas, such as argon or krypton in the sealed unit. This combination of materials slows down heat loss and lets solar heat in, while it reflects unwanted ultraviolet rays.
  • ENERGY STAR® rating to reduce heating costs by up to 12 per cent. Windows with superior efficiency earn a rating from ENERGY STAR®.

Proper installation is key

Ensure the new energy-efficient windows are properly installed. Select a contractor with a good business reputation or one who participates in an industry certification program like Window Wise. Make sure your contract outlines the full extent of the work, product, total cost including taxes, warranties, and completion date.


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