Replace Your Weather Strip
Older wood doors usually rely on a non-adjustable threshold to keep the weather out. If your old door doesn't seal tight against the threshold, you're wasting energy. You could screw a surface-applied weather strip to the face of the door, but a door-bottom weather strip is a less obtrusive way to create a good seal.
The door bottom we're using is available at most home centers and hardware stores. If you can't find a door bottom that's smooth on one side, you can slice off the barbed flanges from bottoms designed for steel or fiberglass doors.
Cut the bottom of the door to allow enough (but not too much) clearance to install the new door bottom. The goal is to create an even 3/8-in. space between the top of the existing threshold and the bottom of the door. Close the door and measure the largest gap between the door and the threshold. If the gap is less than 3/8 in., calculate how much you'll have to cut off the bottom to equal 3/8 in. Mark this distance on the door at the point you measured. Then use a scribing tool to extend a mark across the bottom of the door.
Remove the hinge pins and move the door to a set of sawhorses. Mount a sharp blade in your circular saw and cut along the line. Protect the surface of the door with masking tape. If you have a veneered door, score along the line with a sharp utility knife before sawing it to avoid chipping the veneer.
Cut the door-bottom weather strip about 1/8 in. shorter than the width of the door and tack it to the bottom of the door with a staple gun. Rehang the door to test the fit. If it's too snug, remove the weather strip and trim a bit more from the door. When the fit is perfect, remove the staples and mount the weather strip.
Seal a Drafty Window
Weather stripping often becomes loose, worn or distorted when the sash drags or when the strip gets sticky and attaches itself to the frame, then pulls loose when the sash is opened. Windows have weather strip on the sash, frame or both. Regardless of its location, the steps for removing and replacing it are the same. Weather stripping is available from your window manufacturer or online. The window brand and glass manufacturer date are etched in the corner of the glass or in the aluminum spacer between the glass panes. You'll also need the height and width of your sash (take these measurements yourself).
If the weather strip is in good shape and loose in only a few places, like the corners, apply a dab of polyurethane sealant to the groove and press the weather strip into place. Otherwise, replace the entire weather strip. First remove the sash and set it on a work surface so you can access all four sides. If the weather strip is one continuous piece, cut it apart at the corners with a utility knife.
Starting at a corner, pull the weather strip loose from the sash. If the spline tears off and remains stuck in the groove, make a hook from stiff wire to dig it out.
Work the new weather strip into the groove, starting at a corner. You'll hear it click as the strip slides into the groove.
Seal Basement Air Leaks
Sill plates and rim joists are usually poorly insulated (if at all) and very leaky. So if you have an unfinished basement, grab some silicone or acrylic latex caulk to seal the sill plate. If you simply have fiberglass insulation stuffed against the rim joist, pull it out. Run a bead of caulk between the edge of the sill plate and the top of the foundation wall. Use expanding spray foam anywhere there are gaps larger than 1/4 in. between the sill and the foundation. For hollow-block foundations, stuff fiberglass insulation in the holes, then seal it with expanding foam.
Caulk along the top and bottom of the rim joists and use expanding foam to seal around holes for electric, water and gas lines. Then cut rigid foam insulation to size and place it around the rim joist. Caulk around all four sides of the foam insulation. Check out 9 more home energy conservation tips for winter.