How to Draught-Proof Doors and Windows in a UK Home
Practical draught-proofing for doors, windows, letterboxes and keyholes, including where to look, which products to choose and when ventilation must stay.
Draughts make rooms feel colder than the thermostat suggests, and they push up heating bills as warm air escapes and cold air takes its place. Draught-proofing is among the cheapest, most satisfying jobs in a home, and most of it needs only basic tools. The one catch is that some ventilation must stay.
Find the draughts first
On a breezy day, move a hand or a lit incense stick slowly around the following places and watch for movement or wavering smoke:
- Edges of external doors and the threshold
- Letterbox and keyhole
- Window sashes and frames, and where frames meet the wall
- Loft hatch
- Gaps around pipes where they go through walls or floors
- Skirting boards and floor edges, especially on suspended timber floors
- Chimney fireplaces that are not in use
Make a note of each leak. That list is what you will draught-proof.
Doors
- Perimeter strips. Self-adhesive foam, rubber or brush strips along the door frame close gaps at the sides and top. Choose a thickness that lets the door close without needing force. Clean the surface first so the strip sticks.
- Threshold seal. A brush or rubber seal along the bottom of the door, or a threshold strip fixed to the floor, blocks the gap at the base. Measure the gap at several points because it may vary.
- Letterbox flap. A brush or flap fitted to the inside stops wind coming through. If you are fitting a new letterbox, see how to fit a letterbox.
- Keyhole cover. A simple escutcheon or cover plate blocks the draught.
- Door furniture. Check that the door closes firmly; a latch that does not engage may cause draughts. See how to fix a sticking door.
Windows
- Compression strips suit casement windows that close against a frame. Apply along the frame where the window shuts.
- Brush strips are better for sash windows, where the sliding parts need to move.
- Silicone or caulk around the outside frame fills gaps where the frame meets the masonry. Use exterior-grade sealant and apply after cleaning and drying. See how to deal with mould around sealant for sealant choice in damp areas.
- Secondary glazing film or panels reduce heat loss through the glass itself, not just the gaps.
Avoid sealing trickle vents or air bricks. They provide essential ventilation and help prevent condensation and mould.
Other places
- Floors and skirting: flexible sealant along the join between skirting and floor stops draughts under suspended timber floors. Special gap sealers exist for floorboards.
- Loft hatch: foam strip around the hatch and an insulated lid reduce heat loss.
- Pipes: fill gaps around pipe entries with expanding foam, or flexible sealant where there is movement.
- Unused chimneys: a chimney balloon or a cap with ventilation can block draughts, but consult a professional if a flue serves an appliance.
Safety: do not block ventilation
Open-flued gas fires, boilers and some heaters need a supply of air to burn safely. Blocking ventilation can lead to dangerous carbon monoxide build-up. Do not seal vents that serve fuel-burning appliances, and make sure you have a working carbon monoxide alarm. Gas appliance work belongs to a Gas Safe registered engineer; see can a handyman do gas work?.
Also keep bathrooms and kitchens ventilated. A sealed house without enough ventilation can develop condensation and mould.
What it costs
Materials are cheap: a roll of foam strip, a brush seal and a tube of sealant often cost little. Labour for a whole home may take half a day; see what draught-proofing typically costs. A handyman can do the lot in a single visit, and it fits well with batching jobs.
Getting help
If you would rather not do it yourself, you can send a request through Compito with your postcode and a list of doors and windows. You can message providers about the details, accept an offer, pay online and leave a review after the booking is complete.
A one-afternoon plan
If you want to do the whole house in a single afternoon, work in this order so you finish the high-impact jobs first:
- Walk round with the incense test and write the list.
- Do the front and back doors: perimeter strip, threshold seal, letterbox, keyhole.
- Fit strips to the windows in the rooms you use most.
- Seal the loft hatch and any pipe entries.
- Finish with sealant at skirting boards and external frames, then re-test.
Common mistakes
- Using strips so thick that the window or door will not close, which damages the frame and the latch.
- Sticking foam onto dusty, damp or painted-over surfaces that will not hold it.
- Sealing the bottom of a door in a room with an open-flued appliance.
- Painting over strips, which hardens them and ruins the seal.
- Doing the windows but ignoring the letterbox and the keyhole, which are often the biggest leaks.
Renting or living in an older home
Tenants can often use removable strips, door snakes and letterbox brushes without needing permission, but check the tenancy agreement before changing frames or fittings. In period or listed properties, keep original ventilation paths and ask the local council before altering windows. If you notice condensation after draught-proofing, increase ventilation rather than removing the seals completely; see how to deal with mould around sealant.
Frequently asked questions
Will draught-proofing cause condensation?
It can, if ventilation is blocked. Keep trickle vents, air bricks and extractor fans clear and open windows briefly in wet rooms.
How long do draught strips last?
Cheap adhesive foam can last a season or two, while better rubber or brush seals last longer. Replace them when they flatten or peel.
Can I draught-proof sash windows?
Yes, with brush seals and careful sealing of the frame. Specialist sash restoration is another option for older windows.