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Windows & doors

Windows and doors can account for up to 25% of total house heat loss. If they are in poor condition, they can add even more to your home’s heating and cooling bills.

By repairing or replacing your windows and doors you can:

  • increase comfort - keep out cold winter drafts and make your home more comfortable;
  • save money - exterior doors and windows that are in poor condition can add needlessly to your home’s heating bills.

In addition to these benefits, a well-executed door and window retrofit can improve the appearance and value of your home, reduce the potential for a condensation problem, reduce outside noise, and reduce fading of furniture and carpets due to UV rays.

If you are looking to upgrade windows or doors, choose products that meet ENERGY STAR® requirements which are best suited for our climate.


Check the condition of your windows to determine if they should be repaired or replaced. They should open and close easily. Check the condition of the panes of glass, frames, and hardware. Some windows may only need minor repairs, upgrades, or air sealing while others may need to be replaced entirely.

To improve the energy efficiency of existing windows:

  • repair defective hardware and replace ineffective sash locks to reduce air leakage;
  • caulk all gaps between the trim and wall as well as the trim and the window frame to reduce air leakage;
  • ensure weatherstripping is flexible and properly located with full contact between the sash and frame to reduce air leakage in operable windows;
  • install storm windows to create an insulated air space that reduces heat loss or gain, condensation, and prolongs the life of the main window;
  • replace the existing glazing with energy efficient glazing.

If it’s time to replace the windows, consider:

  • window type: while fixed windows have lower air leakage and are less expensive, operable windows allow for ventilation and emergency exit;
  • options such as triple pane, low emissivity (low-e) coatings, and insulating spacers will minimize heat loss and condensation problems;
  • frame materials affect the insulation value, strength, maintenance requirements, and longevity of a window and can include wood, metal, fibreglass, or PVC;
  • overall window Energy Rating (ER) includes heat flow, air tightness, and solar gain; a higher ER is better;
  • “gas fills” with inert gases, such as argon or krypton, can be used to fill the space between the glass panes to reduce heat loss;
  • spacers are the material that separates the panes when making a sealed glass unit; low-conductivity (warm edge) spacers keep the glass around the edges of the window warmer, reduce condensation, and improve energy performance;
  • warranties differ from supplier to supplier and window to window; compare before you purchase.

If you plan an extensive project of sealing, caulking, and weatherstripping ensure your home has an adequate ventilation system. Contact a professional HVAC contractor to accurately assess your ventilation system.


Inspect your doors for ease of operation, excessive warpage or rot, and the condition of any glass inserts. If the door is in reasonable condition it may be more cost effective to repair any defects and seal the door against air leakage than it is to replace it. However, replacing doors can improve the appearance and security of your home.

To improve the energy efficiency of existing doors:

  • caulk all gaps between the trim and wall to reduce air leakage;
  • ensure weatherstripping is flexible and properly located to reduce air leakage;
  • install door bottom seals or sweeps on doors with no existing bottom weatherstripping.

When replacing doors consider:

  • doors that meet ENERGY STAR® requirements;
  • wood, vinyl, fibreglass, or thermally broken metal frames;
  • good quality weatherstripping;
  • glazing with low-e and an inert gas fill.

For a list of ENERGY STAR® certified windows and doors, visit the Natural Resources Canada website.

Certain renovations can change the way air leaks into and out of your home, and may have an impact on your home’s humidity levels. Read more about managing humidity.