Sealing Drafts: Doors & Windows
Drafts are the most annoying kind of heat loss, you feel every one of them. The good news: doors and windows are also the easiest leaks to fix. Most of these jobs take an afternoon, need only basic tools, and cost less than a tank of gas.
Start by finding the drafts
Do the walk-through from our heat-loss guide first, hand test on a windy day, incense test around frames. Mark every leak with painter's tape. You'll fix the taped spots in order of worst to mildest.
Doors: weatherstripping and sweeps
Doors leak at the edges, not through the middle. Here's what to use where:
- V-strip (tension seal): springy folded strips that press against the door when it closes. Durable, nearly invisible, and the best choice for the sides and top of the frame.
- Foam tape: self-adhesive and dead simple to install, press it into the frame where the door meets it. It compresses over a season or two, so treat it as a consumable and replace as needed.
- Door sweep: a strip that mounts to the bottom of the door and brushes the threshold. If you can see daylight under a closed door, you need one of these.
- Threshold adjustment: many thresholds have screws that raise or lower them. A quarter-turn can close a gap the sweep can't reach.
After installing, close the door on a dollar bill at several points around the frame. If the bill slides out easily, that spot still needs work. If it holds firm, the seal is good.
Windows: caulk, film, and latches
- Caulk the outside: where the window frame meets the siding or brick, old cracked caulk lets water and air in. Scrape out the failed caulk and run a fresh bead of exterior-grade caulk on a dry day above freezing. Never caulk a window shut, caulk belongs on the frame-to-wall joint, not between moving parts.
- Shrink-film kits: clear plastic film taped over the whole window and shrunk tight with a hair dryer. It looks nearly invisible and adds a still-air layer that noticeably cuts drafts on old windows. A solid one-season fix.
- Rope caulk: putty-like cord you press into gaps around window sashes for the winter, then peel off in spring. Great for windows you don't open in winter.
- Latch them: a window that's closed but not latched can leak as much as one left cracked. Walk the house and latch every window fully, free, and surprisingly effective.
The cheapest fixes of all
- Draft stoppers ("door snakes"): fabric tubes laid against the bottom of interior or exterior doors. Ugly? A little. Effective against a whistling gap under the basement door? Very.
- Outlet gaskets: thin foam gaskets that fit behind outlet and switch covers on exterior walls. A whole-house pack costs little and takes an hour to install (turn off the breaker for each outlet first).
- Heavy curtains: floor-length curtains closed at night add an insulating layer over windows. Open them on sunny days to let free solar heat in.
A weekend game plan
Saturday morning: draft hunt with the incense test; buy V-strip, foam tape, a door sweep, and exterior caulk. Saturday afternoon: weatherstrip the two worst doors. Sunday: caulk the worst window frames outside, film the draftiest windows, gasket the outlets. By Sunday night the house will feel different, fewer cold spots, fewer mysterious breezes, and a heating system that cycles a little less often.