Why Draughts Matter More Than You Might Think

If you have ever sat near a door on a cold evening and felt a steady trickle of air against your ankles, you already know the problem. That trickle is warm air leaving your home and cold air taking its place, and it happens far more often than most of us realise. A gap of just a few millimetres beneath a door can let through enough air to noticeably cool a room, and the cumulative effect around an older house can add a surprising amount to your heating bill each winter.

The good news is that you do not need to be a seasoned tradesperson to fix most of it. A handful of inexpensive materials, a few basic tools and an afternoon of your time will deal with the majority of draughts around doors and windows. Below are the repairs that make the biggest difference, along with practical guidance on doing them properly.

Find the Draughts Before You Buy Anything

It is tempting to order a job lot of draught-proofing materials and start sticking them to everything, but you will get better results by identifying the actual problem areas first. On a windy day, close all internal doors and windows, then work your way around each room.

• Hold the back of your hand close to the edges of doors, window frames, letterboxes and keyholes.
• Light a thin candle or incense stick and watch the smoke. It will waver or drift towards a gap, even a small one.
• Check the bottom of external doors, where a visible line of daylight often shows through.
• Look at sash windows in particular, where gaps frequently appear between the moving sashes and the frame.
• Do not forget internal doors leading to cold spaces such as garages, cellars or unheated hallways.

Make a note of each spot and roughly how wide the gap is. Thin gaps under 5mm need different treatment from a 15mm gap beneath a front door, and knowing the sizes will save you a second trip to the shop.

Draught-Proofing Strips for Window Frames and Door Edges

Self-adhesive foam or rubber strips are the simplest starting point for narrow gaps around window frames and the sides of doors. They cost very little, come in various thicknesses, and can be cut to length with household scissors.

Clean the surface thoroughly before applying anything. Dust, old paint flakes and grease will stop the adhesive from gripping, and a strip that peels off within a fortnight is worse than useless. Wipe the frame down with a damp cloth and let it dry completely. Press the strip firmly along the length of the gap, then close the door or window to check that it still latches properly. If it feels tight, switch to a thinner profile rather than forcing it shut.

For metal or uPVC frames, look for strips rated for outdoor use, as standard foam can perish in sunlight. Where a gap is uneven, you may need to build up two thinner layers rather than using one thick strip.

Brush Seals and Draught Excluders for the Bottom of Doors

The gap beneath an external door is often the single worst offender in the house. Brush seals are ideal here. They consist of a carrier that screws or sticks to the door, with stiff nylon bristles that sweep against the floor or threshold as the door opens and closes.

• Surface-mounted brush seals fix to the face of the door and are straightforward to fit with a few screws.
• Concealed or rebated seals sit in a groove cut into the bottom edge of the door, giving a tidier finish but requiring a little more skill.
• Clip-on seals are useful for uPVC doors where drilling is best avoided.
• Traditional draught excluders — fabric sausages or weighted cushions placed against the door — are a quick, no-tools fix for rooms you use infrequently.

Measure the width of the door carefully, and check that the seal will not drag on a thick carpet or catch on a raised threshold. Trim the bristles slightly if they are too long, and always test the door closes and locks before considering the job finished.

Silicone Filler and Sealant for Fixed Gaps

Not every draught comes from something that moves. Gaps between a window frame and the surrounding wall, cracks around a door frame, and holes where pipes or cables pass through are all fixed openings that let in cold air. These are best filled with a flexible sealant.

Use a decorator's caulk for interior gaps that will be painted over, and a silicone or hybrid sealant for exterior work where weather resistance matters. Apply with a cartridge gun at a steady angle, pushing the nozzle along the gap rather than pulling it, which helps the sealant fill properly. Smooth it with a damp finger or a profiling tool before it skins over.

For larger voids, pack the gap with a foam backer rod first so you are not trying to fill a deep hole with sealant alone. Avoid overfilling, as excess can look untidy and make painting difficult later. Allow the manufacturer's stated curing time before exposing the area to rain or heavy drafts.

Keyholes, Letterboxes and Other Overlooked Openings

Once the main doors and windows are sorted, small fittings often remain the last source of chill. They are cheap to deal with and take only minutes.

• Fit a keyhole cover or escutcheon with a brush or flap to stop air whistling through a lock.
• Add a letterbox brush or a sprung flap on the inside of the front door.
• Seal around extractor fans and vents that are no longer needed, provided you are not blocking essential ventilation.
• Check chimneys that are no longer in use and consider a chimney balloon or draught excluder.
• Look at loft hatches and cellar doors, which are frequently overlooked.

Ventilation matters, though. Bathrooms, kitchens and rooms with gas appliances need a supply of fresh air, so never seal these spaces completely just to keep the cold out.

Getting the Best Results From Your Efforts

Take your time, work methodically from room to room, and check your work with the same smoke or hand test you used at the start. Small gaps that you have missed will quickly become obvious on a windy day, and it is worth revisiting doors after a few weeks to make sure seals have not shifted or compressed.

If you are dealing with a listed property, a very old front door, or a window that no longer closes squarely, it may be worth calling in a local joiner or window specialist. A poorly fitting frame is often the root cause, and no amount of draught-proofing will fully compensate for a door that has dropped on its hinges or a sash that has warped with age.

For the vast majority of homes, though, a modest spend on strips, brush seals and sealant, combined with a Saturday afternoon of careful work, will make rooms noticeably warmer and take real pressure off your heating bills right through the colder months.