Why Draft-Proofing Matters
A thin ribbon of cold air sneaking under a door can drop the felt temperature in a room by 3°C. Block that gap and the thermostat can be turned down, cutting heating costs without touching the boiler. Sealing is cheaper than insulating walls and pays back in one season.
Find Every Leak in 15 Minutes
Close every window and exterior door, switch on kitchen and bathroom fans to create a slight suction, then move a lit incense stick along frames. Where the smoke wavers or blows inward, you have a leak. Mark each spot with painter’s tape so you can circle back with supplies.
Best Weatherstripping for Windows
V-strip tension seal
Self-adhesive vinyl or spring-metal folds into the gap and springs back when the sash closes. Works on sashes that slide up, sideways or tilt. Clean the stop molding with rubbing alcohol, press the strip in place, then close the window to compress. Expect a 5-year life before the plastic turns brittle.
Closed-cell foam tape
Cheapest fix for double-hung windows. One roll seals four average sashes. Pick the 3/8 in thickness if you can slide a postcard through the crack. Compress the foam 30-50% for a tight seal without bowing the frame.
Tubular rubber gasket
Best for casements and awning windows that clamp shut. Screw-on types last longer than adhesive; pre-drill pilot holes every 4 in to prevent splitting the wood.
Door Sealing Strategy
Bottom sweep
Aluminum or stainless strip with a vinyl flipper sheds rain and blocks air. Measure the door width, hacksaw the track 1/16 in short so it does not scrape the jamb, then screw to the face. Leave a 1/4 in gap to the threshold so the vinyl flexes rather than folds.
Threshold seal
If daylight shows under the door, first try turning the bronze adjustment screws in the sill plate clockwise. No screws? Stick a 1/2 in adhesive foam pad to the threshold; compress it 50% when the door closes.
Jamb kit
A peel-and-stick V-strip on the stop and a 3/8 in doorstop bumper at the top corners ends side leaks. Align so the door just kisses the seal when latched.
Caulk Like a Pro
Use acrylic-latex plus silicone for interior trim; it paints smooth and flexes 25%. Pure silicone is for outside brick-to-frame joints; it lasts 50 years but will not take paint. Cut the nozzle at a 45° angle, poke the foil seal with a wire, then squeeze while dragging the gun backward. Tool the bead with a plastic spoon dipped in dish-soap water; the curve leaves a uniform 1/8 in joint.
Hidden Gaps Most People Miss
- Attic hatch: stick 1/2 in foam tape on the lip and latch tightly.
- Baseboard top: run a paintable white caulk line where molding meets drywall.
- Drywall to window returns: shoot low-expansion foam into the rough opening gaps, then trim flush.
- Outlet boxes on exterior walls: fit a premade foam gasket under the cover plate.
Supplies List Under $40
One 17-ft roll V-strip vinyl: $7
20-ft closed-cell foam tape: $4
Two door sweeps: $12
10-oz paintable caulk: $3
Low-expansion foam can: $6
Incense sticks: $2
Total: $34 plus tax at any hardware aisle.
Step-by-Step Weekend Plan
Saturday morning (2 hrs)
1. Smoke test every room; tag leaks.
2. Remove old cracked stripping with a putty knife.
Saturday afternoon (2 hrs)
3. Apply V-strip to windows; let adhesive cure overnight.
Sunday morning (2 hrs)
4. Caulk window returns and baseboards; smooth with spoon.
Sunday afternoon (1 hr)
5. Install door sweeps and foam gaskets on outlets.
How Much You Can Save
Energy.gov states that air sealing can trim heating and cooling bills by up to 20%. In a typical 1,800 sq ft home that spends $1,200 per year on HVAC, that is $240 back in your pocket the very first year—seven times the cost of supplies.
When to Call a Professional
If the incense flame sucks vigorously toward a wall outlet, you may have chase cavities that open into the attic. Blowing low-expansion foam into live electrical boxes is a fire risk; hire a weatherization crew that can safely drill and pump behind walls. Likewise, old windows with rotted sashes need rehab, not more tape.
Maintenance to Keep the Seal
Each fall run your hand around closed windows; if you feel cold, replace the compressed foam. Keep weep holes at storm-window bottoms clear so water does not back up and freeze the gasket. Once a year, smear a film of petroleum jelly on exterior door sweeps to keep vinyl flexible.
Quick Fixes for Renters
Use removable 1/2 in putty-type rope caulk that peels off in spring. Temporary draft stoppers—fabric tubes filled with rice—block the door bottom without screws. 3M Command strip V-strip comes off cleanly when you move.
Disclaimer
This article was generated by an AI language model for general information. Results vary by climate and home construction. Follow product instructions and consult a qualified contractor for structural work.