Check for air leaks

With windows and doors closed, hold a lit stick of incense near window and door frames where drafts might sneak in. Watch for smoke movement. Note what sources need caulk, sealant, and weather-stripping.

Seal air leaks around windows

If you have old windows, caulking and adding new weatherstripping goes a long way toward tightening them up.

  • Bronze weatherstripping ($12 for 17 feet) lasts for decades but is time-consuming to install.
  • Self-stick plastic types are easy to put on but don’t last very long.
  • Adhesive-backed EPDM rubber ($8 for 10 feet) is a good compromise, rated to last at least 10 years.

Nifty gadgets called pulley seals ($9 a pair) block air from streaming though the holes where cords disappear into the frames.

Seal air leaks around doors

Check for air leaks, and replace old door weatherstripping with new.

  • Foam-type tape has an adhesive backing; it’s inexpensive and easy to install. If it comes loose, reinforce it with staples.
  • Felt is either adhesive-backed or comes with flexible metal reinforcement. it must be tacked or glued into place. It’s cheap and easy to install, but it has low durability.
  • Tubular rubber, vinyl, and silicone weatherstripping is relatively expensive and tricky to install, but it provides an excellent seal. Some types come with a flange designed to fit into pre-cut grooves in the jambs of newer doors; check your existing weatherstripping and replace with a similar style.

Check exterior trim for any gaps between the trim and your door frames, and the trim and your siding. Caulk gaps with an exterior latex caulk ($5 for a 10-ounce tube).

Seal door bottoms

If a draft comes in at the bottom, check the condition of the threshold gasket. Replace worn gaskets. If you can see daylight under the door, you may need to install a new threshold with a taller gasket ($25 for a 36-inch door). Or, install a weather-resistant door sweep designed for exterior doors ($9). Door sweeps attach directly to the door and are easy to install.