How to Draught-Proof Your Home This Winter: A Complete Guide

Draught-proofing is consistently ranked by the Energy Saving Trust as the most cost-effective home improvement you can make for reducing energy bills. Unlike insulation or double glazing — which require significant upfront investment — draught-proofing is cheap, can be done in a weekend, and typically pays back its cost within a single heating season. For a typical UK semi-detached home, the Energy Saving Trust estimates savings of £45–£80 per year, but in older Victorian or Edwardian properties with single-glazed sash windows and suspended timber floors, the savings can be considerably higher. This complete guide covers every part of your home systematically.

Understanding How Draughts Work

Draught-proofing is more effective when you understand what's happening. A draught is cold air entering the building through gaps. But you can't simply seal every gap and call it done — a house needs some air exchange to prevent condensation, mould and stuffiness. The key is to seal uncontrolled draughts (gaps that let in too much cold air without providing useful ventilation) while preserving controlled ventilation through trickle vents, airbricks to subfloors and purpose-made ventilators.

The principle is straightforward: cold air enters low (gaps in floors, under doors, around skirting boards) and warm air escapes high (gaps around window frames, loft hatches, chimney breasts). Your job is to intercept both journeys.

External Doors: The Biggest Bang for Your Buck

External doors are typically responsible for around 20–25% of heat loss through draughts in a poorly sealed home. The good news is that door draught-proofing is cheap and simple.

Door threshold strips

The gap under the front door is usually the most significant single draught source. You'll feel it clearly by holding your hand near the floor on a windy day. Options:

• Brush strip threshold seals: A nylon pile brush attached to a metal bar that screws to the base of the door. The brush sweeps across the threshold as the door opens and closes without resistance. These are the most practical solution for most UK front doors. Exitex and Stormguard make good quality versions available at Screwfix for £8–£20 depending on length. Measure the door width accurately — they're sold in standard lengths and you'll need to trim to fit.
• Automatic drop-down seals: A more sophisticated option where the seal automatically lowers when the door closes and lifts when it opens. Excellent performance, costs £25–£60. Worthwhile for doors with significant floor level changes or where aesthetics matter.
• Draught excluder (fabric): The door snake — that long fabric tube your grandmother probably used. Effective enough in a pinch, but falls over and gets kicked around. A permanent threshold seal is always better.

Door frame seals (sides and top)

Self-adhesive foam strips from any DIY shop are the budget option: B&Q sells Draught Excluder Foam Tape for around £3 per 5m roll. They work, but compress over time and lose effectiveness within two or three years. For a more durable solution:

• Rubber or PVC compression seals: These slot into a groove cut in the door stop and provide a much longer-lasting seal. Exitex and Stormguard sell door frame seal kits at Screwfix (£10–£25). Cut to length with scissors, peel and press.
• Brush pile seals: Work well for sides and top. Particularly effective on slightly warped doors where the gap isn't perfectly even.

Fitting time: 30–45 minutes per external door. Total material cost: £15–£40 per door. A worthwhile investment in any UK home.

Windows: Casements, Sashes and Fixed Frames

Casement windows

Modern uPVC casement windows typically have compression seals fitted as standard. These degrade over time — if your windows feel draughty but close and lock properly, the seals probably need replacing. Replacement gaskets can be ordered from window specialists or cut from draught-proofing seal roll. Look for the type that matches your existing groove profile.

Older timber casement windows often have large gaps around the frame where the wood has shrunk. Self-adhesive foam strip is a quick fix. For a longer-lasting solution, use rubber V-strip (also called tension seal) which lasts far longer than foam and gives a neater appearance.

Sash windows

Sash windows in Victorian and Edwardian homes are notorious for draughts, and can be responsible for a significant fraction of total heat loss in older properties. Replacing them with double-glazed sashes can cost £500–£1,500 per window. Draught-proofing the existing sashes costs a fraction of that and can be remarkably effective.

Purpose-made sash window draught-proofing kits are available from specialist suppliers. The best systems use:

• Mohair pile strips on the meeting rail (where the two sashes overlap)
• Blade seals on the staff and parting beads to seal the sides of the sashes
• A brush or wiper seal on the top rail of the upper sash and the bottom rail of the lower sash

SashStop and Ventrolla are UK specialists who offer full sash draught-proofing kits and professional installation. DIY kits cost £50–£100 per window and take 3–4 hours; professional installation runs £150–£300 per window but is considerably neater.

Trickle vents

Do not seal trickle vents — the small slotted vents fitted at the top of window frames, standard on all double-glazed windows installed since around 1995. They are there for a reason: to provide background ventilation to prevent condensation and maintain air quality. Sealing them can cause condensation, mould growth and in extreme cases structural moisture damage.

Floors: Suspended Timber and the Subfloor

Suspended timber ground floors — found in most pre-1920 UK housing — sit above a void that is (correctly) ventilated to the outside to prevent timber rot. This means cold air circulates freely below the floor and rises through gaps between floorboards and around the edges where boards meet skirting boards.

Filling gaps between floorboards

• Flexible filler: For small gaps, use a flexible decorating filler like Polyfilla Flexible Gap Filler applied with a caulking gun. It flexes as the boards move with moisture changes rather than crumbling out. Cost: £6–£10 per tube.
• Wooden slivers: For larger gaps, cut thin slivers of timber to glue into the gap. PVA glue, press in, plane flush when dry. Time-consuming but very effective and sympathetic to period properties.
• Draught-proofing products: Draughtex and similar products are foam strips pushed into floorboard gaps with a putty knife. Fast to apply, works well, costs around £15 per roll (covers approximately 20m of gap).

Skirting boards and floor edges

Run a bead of flexible silicone or caulk along the junction between the skirting board and the floorboard. This seals the cold air pathway around the floor perimeter. Use a paintable decorator's caulk if you plan to paint the skirting — Polycell Decorators Caulk is a standard UK choice at £4–£6 per tube.

Airbricks: Don't block them

Airbricks in the external walls at ground level provide ventilation to the subfloor void. These must never be blocked — doing so causes the subfloor timber to retain moisture and rot, which is an expensive structural problem. If you have airbricks, check they're clear of leaves and soil, not that you block them in the name of draught-proofing.

Chimneys: The Forgotten Draught Source

An open chimney flue acts like a permanent extractor fan, constantly drawing warm air out of your home and pulling cold air in at ground level to replace it. Even a fireplace with a closed damper loses significant heat through the flue.

Options for unused chimneys

• Chimney balloon (draught excluder): An inflatable balloon that sits in the flue above the fireplace opening, blocking airflow. Chimney Balloon brand products are available for £20–£35 from Amazon or specialist suppliers. They're removable and reusable — critical if you ever want to light the fire again. They come in various sizes; measure your flue cross-section before ordering. Must be labelled clearly so nobody lights the fire with it in place.
• Chimney sheep: A wool fleece pad on a flexible plate that wedges into the flue. Available from chimneysheep.com for around £30. Excellent performance, slightly more sustainable option.
• Permanent sealing: If the chimney is genuinely never going to be used, a builder can cap it from the top and fit a ventilation cowl (to prevent damp), then seal the fireplace opening with board and plaster. Requires a small vent in the fireback to allow the stack to breathe. Permanent and effective, but commits you to never reopening the fireplace.

Loft Hatch: The Overlooked Gap

The loft hatch is a cold air portal that most people ignore. Even a 3–4mm gap around a standard loft hatch creates a significant draught because of the temperature differential — warm air below, very cold air above in the loft space.

Fit self-adhesive foam draught strip around the hatch frame rebate, exactly as you would for a door. Add a hook-and-eye latch or compression catch to pull the hatch tight against the seal. The whole job takes 20 minutes and costs under £5. Also check that the top of the loft hatch board is insulated — 100mm of rigid insulation board on the room-side of the hatch (facing up into the loft) makes a significant difference.

Pipework, Cable and Service Entry Points

Every pipe and cable that penetrates an external wall or floor creates a potential draught path. Gas pipes, water pipes, electric cables and phone lines all need to be sealed around their entry points. Use a flexible silicone sealant — EverBuild or Geocel make good general-purpose silicone sealants available at Screwfix for around £5–£8 per tube. For larger gaps around pipes, Gyproc EasiFill 60 or expanding foam (Teapo or Soudal) can fill the void before silicone is applied over the top.

Summary and Prioritisation

If you're working through a whole-house draught-proofing project, prioritise in this order for maximum impact:

1. External doors (threshold seals and frame seals) — highest impact per pound spent
2. Chimneys and fireplaces (fit balloon or sheep if unused)
3. Sash windows (if present — often a major source in Victorian homes)
4. Suspended timber floors (gaps between boards and around skirting)
5. Casement and fixed windows (frame seals and gap filling)
6. Loft hatch (quick win, low cost)
7. Pipework entry points (systematic sweep around all penetrations)

Budget for a full draught-proofing project in a three-bedroom semi: £100–£250 in materials, done over two weekends. Annual savings of £60–£120 on a typical gas-heated home. With energy prices where they are, that's a simple financial calculation — and a noticeably more comfortable home through the winter months.