Tighten up doors and windows
If doors and windows don't close completely, they can let cooled or heated air escape, or they can let in winter cold and summer heat. Many times, just a little tightening up is all that's needed.

• Fix Doors and Windows - A double hung window may be missing the lock, which keeps the upper sash closed. Outside doors that don't close completely may need to be re-fitted or re-hung, but often all that is needed is simply to adjust the striker plate or plane off an eighth of an inch.
• Adjust Automatic Door Closers - The closer may shut the door slowly, or not completely. Frequently there's a simple adjustment that can be made with a screwdriver.
• Close the Gap - Gaps which leak air and energy dollars can be found in many places; where doors meet each other; where parts of windows meet; and where doors and windows meet the walls.
• Replace Broken Glass - Quite obviously, broken or missing panes can let a lot of air out or in.
• Shade Your Windows - Adjust shades and blinds, or install window film to control the sun's heat.

Cover window air conditioners
Cover the exterior portion of the unit during cold weather. If left uncovered, even with vents closed, these units can let in cold air.

Seal cracks
Air-leaking cracks may be present for several reasons: the building was not tightly constructed in the first place; cracks developed as the building aged; or the original sealing material has dried out and pulled away. Inspect the outside to locate cracks and other obvious openings. On the inside, look for cracks of daylight and feel for drafts. Make sure to check for air leaks:

• In the attic or crawl spaces
• In utility rooms
• Around window and door frames
• Where the walls meet the foundation
• In the foundation itself
• Where walls join at corners
• Around window air conditioners and other equipment installed in walls or the roof
• Around places where piping, electrical conduits, or telephone lines enter the building
• Around the chimney of a furnace or boiler

Start with the largest and easiest-to-fix openings first and seal as follows:

• Small Crack - caulk where there is none and replace worn-out caulking
• Large Cracks - first fill with foam 'stuffers' or galss fiber insulation then caulk
• Masonry Cracks - may require cement rather than caulk
• Around Flue Chase - install sheet metal to close opening
• Outlet Boxes - install pre-cut foam insulating pads
• Large irregular holes - Use expanding foam

When using caulk to seal air leaks use the highest quality caulking materials and follow the manufacturers' directions (some caulks require temperatures above 40 degrees F and all require the surface to be cleaned first).