How to Draught-Proof Your Home Before Winter

Draughts are one of the most common reasons homes feel cold despite the heating being on. Warm air rises and escapes, cold outside air fills the gap, and your boiler works harder than it needs to. The good news is that most draught sources are simple to fix yourself — and the materials cost very little.

This guide goes through the main places cold air gets in and what to use to stop it.

Start by Finding the Draughts

The easiest way to find draughts is on a cold, windy day. Hold a lit incense stick or a thin strip of tissue near doors, window edges, skirting boards, and floorboards. Where the smoke or tissue moves horizontally, cold air is getting through. Focus on:

• The gap under external doors
• Around door and window frames
• Letterboxes and keyholes
• Loft hatches
• Skirting boards (especially on ground floors with suspended timber floors)
• Chimney openings (if unused)

Under Doors

The gap under an external door is usually the biggest source of cold air in a house. There are two main solutions:

• Draught excluder brush strip: A self-adhesive or screw-fixed strip with a nylon brush that runs along the bottom of the door. It brushes against the floor as the door opens and closes, sealing the gap without stopping the door from moving. Best for exterior doors where the gap isn’t uniform.
• Door draught excluder snake: A fabric tube that sits along the base of a door from the inside. Simple, no fitting required, and easy to move if needed. Fine for internal doors where draughts are less severe.

Around Doors and Window Frames

Cold air often sneaks in around the edges of doors and windows rather than through the glass itself. Self-adhesive foam draught-sealing strip is the standard fix — it’s the fastest DIY job there is. Cut to length, peel the backing, and press it into the rebate (the slot the door or window closes against). Make sure the surface is clean and dry before sticking, or it won’t stay put.

For gaps that are irregular or too large for foam strip, use rubber or silicone seal strip instead — it compresses further and gives a better seal on uneven frames.

Letterboxes and Keyholes

Both are direct holes through an exterior door.

• Letterbox: Fit a draught-excluding letterbox flap or brush seal on the inside of the door. These press into the existing letterbox frame and have a brush or flap that falls back into place after post is delivered. Easy to fit with a screwdriver in about 10 minutes.
• Keyhole: A keyhole cover or escutcheon with a spring-loaded flap covers the hole when the key isn’t in it. It makes a noticeable difference in exposed locations.

Skirting Boards and Floorboards

In older homes with suspended timber floors, cold air rises through gaps between floorboards and between boards and skirting. Flexible sealant or decorator’s caulk fills these joints neatly. Use a gun-applied tube and smooth with a wet finger. Make sure the gap is clean and free of dust before applying. For wider gaps between boards, draught-excluding filler strips are a better option than caulk.

Loft Hatches

Loft hatches are often overlooked but they sit above a large cold air reservoir — the loft. Treat them like a door: foam strip around the frame edge, and if the hatch itself isn’t insulated, add a layer of rigid insulation board to the top face.

Unused Chimney Flues

An open chimney is a direct vent to the outside. If the fireplace is genuinely unused (no wood burner, no gas fire), a chimney draught excluder balloon or a chimney sheep plug blocks the flue from inside. These are removable if you ever want to use the fireplace again. Put a small sign by the fireplace reminding you to remove it before lighting anything — it’s a common mistake to forget it’s there.