There are many ways to improve the energy efficiency of the doors and windows in your residence and thus reduce your heating costs.

Inspect your window frames
Contrary to what you might think, the frame of a window is as important as the glass or glazing. If the joint between the frame and the structure is not airtight and watertight, it can be easily rectified. Place fibreglass insulation loosely between two beads of slightly compressed ethafoam. Minimal expansion urethane sealant will also do the trick.

Make your windows leak-proof
If your windows perform poorly, make them airtight and waterproof. For sash windows, add tubular or V-shape weather stripping. If you use storm windows doubled onto regular windows, install them early in the heating season.

Replace your windows only if the frames are in bad repair or if it is impossible to make them airtight. Sealed windows (double glazed) that have traces of moisture between the two panes of glass have lost their initial sealing. Rather than changing the entire window, simply replace the glass with high-energy efficiency glass which will cost much less.

Apply transparent film to your windows
If there are some windows you don’t need to open during the winter, installing a transparent plastic sealing film with a portable hair dryer will make your windows much more airtight.

Install weather stripping to block cold air drafts
It is important to keep all doors that lead to the outside and also those that open onto unheated rooms in good repair. Properly installed weather stripping blocks drafts. Before installing the strips, tighten all the screws in the door hinges. If correctly installed, the door will close easily and tightly, compressing the weather stripping with no need to shut with force. Never paint weather stripping, or it will lose its elasticity. For the doorsill or threshold, install a door sweep weather strip either on the threshold or on the door itself. For letter slots, install a storm flap and locking covers.

Source: Agence de l’efficacité énergétique du Québec