Improving the energy performance of doors and windows in a home

There are several ways to improve the energy performance of a home’s doors and windows to reduce heating costs.

Contrary to popular belief, heat loss does not always come from the doors and windows themselves; the problem often lies in the way they were installed.

To fix drafts, it is often more effective to improve their perimeter—that is, by caulking the space between the door or window frame and the wall—than to replace the doors or windows altogether.

Air leaks around a window indicate that the joint between the frame and the house structure is no longer airtight.

To reduce these air leaks, apply a caulking product around the frame where it meets the wall.

If the trim or woodwork can easily be removed and reinstalled, you can take it off and reduce leaks by insulating and caulking the gap—for example, with low-expansion urethane foam.

If your home’s windows are no longer performing well, make them airtight. For double-hung windows, install V-shaped or tubular weatherstripping.

If you have storm windows (double sashes), install them at the start of the heating season.

Only consider replacing your windows if the frames are too damaged or cannot be made airtight against air infiltration.

Insulated glass units (thermos) showing moisture between the two panes have lost their original seal. Instead of replacing the entire window, replace only the glass with a high-performance energy-efficient pane—at a lower cost.

If you do not need to open certain windows during winter, applying a transparent plastic film tightened with a hair dryer will significantly improve their airtightness against air infiltration.

Properly installed weatherstripping blocks drafts.

• Before installing weatherstripping around a door, tighten the hinge screws securely. The weatherstripping must be installed so that the door closes properly and compresses it without undue force.
• Never paint weatherstripping; this will help it retain its elasticity.
• For door thresholds, install a door sweep on the threshold or on the door itself.
• For mail slots, install flaps and keyed covers.

It is just as important to maintain doors leading to the outdoors as those opening onto unheated rooms.

Replacing doors and windows is not always necessary to improve a home’s energy performance. An energy efficiency advisor can help you identify problems and determine the most suitable solutions for your home through a visual inspection of your windows and an airtightness (blower door) test.

The Rénoclimat government program offers financial assistance for door and window replacement.