Introduction

Doors leak twice as much air as windows. Coupled with the fact that doors also are used more often than windows, you can see why their seals merit careful inspection.

Check for crimped, flattened, or missing weather stripping at the top and sides. You might be able to adjust spring metal by prying lightly on the spring section. Other types probably will have to be replaced.

Feel along the threshold. Air infiltration means you need to seal the bottom of the door as well. And how's the door itself? Warping, an out-of-square frame, or deteriorated caulk around the edges give air a chance to make an "end-run" around even the tightest weather stripping. Examine storm doors, too. Some metal versions have a bulbous gasket along their lower edges; others employ a sweep. Both must be replaced periodically.

Check out any interior doors that open to an attic, garage, basement, or other unheated space. Builders often don't bother to seal these big heat-losers at all. Worse yet, some contractors cut costs by installing hollow-core doors that have little if any insulation value. If that's the case at your house, your best bet would be to invest in the far greater thermal efficiency of a solid- or foam-core door.

Get free estimates from local handymen.