What Are the Causes of a Window Draft?

Improper Installation

• Drafts may be getting in through chinks around the edges of an improperly installed window frame. If the window has a twisted or bowed frame, the entire unit may need to be replaced. In other cases, caulk and flashing may fix the problem. If the window was put in by a professional, bring your grievances before the installation company and inquire about workmanship guarantees. Contact your local chapter of the Better Business Bureau if necessary.

Inefficient Windows

• In many cases, cooler air close to the windows is a matter of poor heat conduction. If the windows are not efficient insulators, and it's colder outside than inside, the home will rapidly lose heat through the poorly insulated windows. The opposite effect can also occur due to poorly insulated windows in hot climates, where the outdoor air is considerably hotter than the air indoors. Inefficient windows will most likely need to be replaced with models that more efficiently reduce heat transfer.

Troubleshooting Tips

• Hold a lit candle close to the edge of the window frame where it abuts with the wall. If the flame flickers, a current of air is passing between the interior and exterior. Caulking, flashing or a new window will be necessary to fix the gap. If the flame does not flicker, the cold air is due to a heat transfer through the window itself, a problem you can solve with energy-efficient windows.

Additional Solutions

• In most cases of drafts or excess heat transfer, the best thing to do is replace the window or have a professional fix the seal around its frame. However, some small, simple improvements can enhance the window's energy efficiency. For example, it's common for air to pass through a gap at the bottom of an old double-hung window. Line the window sill with a "draft snake," a cloth tube filled with dried rice or beans. The extra insulation will reduce draft around the sill area. Insulating curtains or blinds can further cut down on heat transfer.