How to Draught-Proof Your Home Before Winter (UK Guide)

This is a genuinely high-return autumn job. It’s cheap, most of it is DIY, and unlike almost everything else on this site it pays back immediately and permanently rather than seasonally.

Why it matters more in a windy winter

Air leakage isn’t a fixed quantity. The rate at which cold air is forced through gaps depends on the pressure difference across the building envelope — and wind creates pressure difference.

A gap that leaks gently on a still day leaks considerably harder in a gale, as wind pressurises the windward face and creates suction on the leeward side, driving air through the house. So the same unsealed home costs more to heat in a stormy winter than a calm one at identical temperatures.

Given the outlook for this season — the Met Office’s position is that El Niño raises the chance of milder, wetter and windier conditions in autumn and early winter — draught-proofing is unusually well-timed work. Our winter outlook covers the forecast picture.

The same gaps also admit wind-driven rain, which is how a windy winter turns into a damp problem — covered in our condensation and damp guide.

Step 1: Find the draughts

Do this on a windy day, which is when leaks are most obvious.

• Back of the hand. Move slowly around door and window edges. Skin detects moving air well.
• A lit incense stick or a thin strip of tissue. Hold near suspect gaps and watch for deflection. More sensitive than your hand.
• Look for dust marks. Persistent dirt lines on carpet edges or around skirting often mark where air has been travelling for years.
• Check on a cold morning. Cold spots on a wall or floor can indicate air movement behind them.

Write down what you find before buying anything, so you buy once.

Step 2: Doors

External doors are usually the largest single loss.

• Under the door: a brush strip or a fitted draught excluder. Screw-fixed brush strips outperform loose fabric “sausages”, which move every time the door opens.
• Around the frame: self-adhesive foam, E-profile or V-profile strips. Measure the gap first — too thick and the door won’t close properly, too thin and it does nothing.
• Letterbox: a brush and flap insert. A surprisingly significant leak on an exposed front door.
• Keyhole: a simple escutcheon cover.
• Internal doors matter too if you’re heating one room. Our one-room heating guide covers why.

Step 3: Windows

• Self-adhesive strips around opening casements — same principle as doors, matched to gap size.
• Silicone or acrylic sealant where the frame meets the wall, if the existing mastic has perished or cracked. This also blocks wind-driven rain.
• Secondary glazing film — clear film applied to a frame and shrunk taut with a hairdryer. Cheap, genuinely effective on single glazing, and removable in spring. It looks better than people expect when done neatly.
• Thermal or lined curtains, closed at dusk. Glass is the weakest thermal element in most rooms.
• Leave trickle vents open. They’re deliberate ventilation, not a defect.

Step 4: The ones people forget

This is where the surprising gains usually are.

Unused chimneys. An open, unused flue is effectively a permanently open window in your ceiling, with the stack effect actively pulling warm air out. An inflatable chimney balloon or a removable chimney sheep seals it. Never do this if the fireplace is in use or could be — and leave a small permanent vent, since flues need some airflow to stay dry.

The loft hatch. Frequently a bare board sitting in a rough frame, directly beneath the coldest space in the house. Fit foam strip around the rebate and insulate the hatch itself.

Floorboards and skirting. Gaps between boards, and the junction between floor and skirting, leak significantly in older homes with suspended timber floors. Flexible filler or proprietary gap-filling strip works. Don’t seal the airbricks ventilating the void beneath.

Service penetrations. Where pipes and cables enter under sinks, behind boilers, at the consumer unit — often left as ragged holes straight through to a cold void or outside. Expanding foam or sealant, quick to do, immediately noticeable.

Old extractor fans and vents that no longer serve anything. Redundant vents from a removed appliance can be permanently sealed. If in doubt whether it’s redundant, leave it.

What this is worth

Draught-proofing consistently appears near the top of cost-effectiveness rankings for home energy improvements — a modest materials cost against a saving that recurs every winter, permanently. The Energy Saving Trust publishes current UK saving estimates, which vary by property type and are linked below.

Two benefits people don’t count: comfort at a lower thermostat setting, because draughts make you feel colder than the air temperature suggests, and reduced wind-driven rain penetration, which is a damp prevention measure.

What draught-proofing won’t fix

Being honest about the limits. Draught-proofing addresses air leakage. It doesn’t address conduction through walls, roof and windows.

If your loft insulation is thin, that’s a separate and larger job — Building Regulations guidance points to around 270mm of mineral wool. If a room is cold despite being sealed, the problem is likely fabric or heating distribution rather than draughts. Our cold room guide covers diagnosing that.

Frequently asked questions

Sources

• Energy Saving Trust — Draught-proofing (methods, savings estimates, ventilation warnings)
• Energy Saving Trust — Roof and loft insulation
• GOV.UK — Approved Document F: Ventilation (required ventilation provision)
• GOV.UK — Approved Document L (insulation standards)
• Gas Safe Register — Carbon monoxide safety
• HSE — Carbon monoxide in the home
• Met Office — El Niño and the UK

Related reading: our storm-proofing guide and cold room guide.