Infiltration of cold air from air leaks around doors and windows is as significant a contributor to your heating bill as is poor insulation in the walls and ceiling. An easy way to reduce you heating bill is to reduce these drafts with simple weatherstripping.
- On a day when it's windy outside, close your windows and feel for air leaks. You can use an incense stick for this too if you don't mind the smell. Watch the smoke trail and if it becomes anything other than vertical, you have an air leak. Typically air leaks will be at the edges where the window is hinged, slides or meets another unit, such as between the two panels of a double hung window.
- Although you can tape plastic over the windows to seal them, this can be expensive and look bad. It can also reduce much needed light in the winter unless you use the shrink-wrap type of plastic seal. So a better and easier solution is to use inexpensive rope caulk.
- Press the rope caulk into all the joints where air is leaking.