Best Draught Excluders UK 2026: What to Buy for Each Gap

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There is no single best draught excluder, because there is no single draught. The gap under a front door, the aperture behind a letterplate and an unused chimney are three completely different holes, and the product that seals one does nothing for the other two. Buy the wrong one and you have spent £13 on a cushion while the actual draught carries on.

So this guide is organised by gap rather than by product: what to buy, what it costs, how big the hole actually is, and roughly what closing it is worth on a gas bill at the October 2026 price cap. Prices and ratings were checked on Amazon UK in September 2026 and will drift.

The short version. If you only do one thing, block an unused chimney. If you only spend £17, buy a door brush strip, a letterbox brush cover and a roll of foam tape — an hour's work and the cheapest energy saving available to a UK household.

First, find out which gap is actually costing you money

Draughts are not equal, and people tackle them in the wrong order — fabric sausage first, chimney last. Rank them instead by the area of open hole each one represents.

An older semi with an open chimney, bare floorboards, an unbrushed letterbox, a 10 mm door gap and four leaky windows adds up to roughly 2,230 cm² of permanently open hole — slightly more than a 400 mm × 500 mm window sash left wide open from October to March.

Two entries dominate, and neither is the one people buy first. Floorboards and an unused chimney are three quarters of the problem in a period property. The door you can feel the draught at is under 4% of it.

Area is a proxy, not a measurement. A chimney leaks harder per square centimetre than a gap at floor level, because a warm flue acts as a stack and pulls air up and out even on a still day — so if anything that line understates itself.

What the whole job is worth

Ofgem's medium household uses 11,500 kWh of gas a year, of which roughly 80% is space heating — about 9,200 kWh, or £733 at the cap gas rate of 7.97p per kWh. In an older UK home air leakage accounts for something like 20% of heat loss, so call it £147 a year of gas going straight out through gaps.

You will not recover all of it: filling floorboard gaps gets maybe half of them, and you cannot seal a room airtight and should not try. A realistic result is £60 to £85 a year — exactly the range the Energy Saving Trust quotes for whole-home draught proofing, and the arithmetic above is where that number comes from.

Against that, here is what each fix is worth in proportion to the hole it closes:

The last three are the ones to do this weekend. They cost under £17 together, take an hour, and close 26% of the hole.

Best draught excluder for the bottom of a door

This is the gap most people mean when they say draught excluder, and there are three genuinely different products for it.

Brush strip, screw-fixed or self-adhesive — the right answer for most external doors. A rigid carrier holds a dense nylon pile that sweeps the threshold. It copes with an uneven floor, it does not drag on carpet, and it lasts years rather than months.

The Stormguard bottom-of-door brush seal in white, 914 mm is the default pick at around £7.89, 4.4 stars from over 3,100 reviews. The gold-finish version is cheaper at about £6.49 (4.5 stars, 2,800 reviews), and there is an 838 mm version at around £7.19 for a 2 ft 9 in door. All cut down with a hacksaw — measure the door leaf, not the frame. If you would rather not see the screws, the cover-clip version hides them for about £9.99.

Flexible under-door seal — for internal doors and rented homes. A rubber twin-blade seal that clips or sticks under the door and seals both sides. The Vellure premium door draught excluder strip is the most reviewed product in the category by a distance — around £12.90, 4.4 stars from over 24,000 reviews. Good on a smooth floor, poor on thick carpet, and removable, which matters if you rent.

Fabric sausage — comfort, not sealing. A weighted fabric under-door draught excluder blocks the cold air you feel at ankle height and does make a room feel warmer. What it does not do is seal: it never spans the full gap and it shifts every time the door opens, so on an external door it is out of position within a day. Buy one for a draughty internal door. Do not buy one as your front door solution.

One caveat on internal doors: that gap is often the only ventilation a room gets, especially on a suspended timber floor. Seal the external envelope hard and leave internal doors alone unless a specific room is uncomfortable.

Best draught excluder for door frames and windows

The gap around the closing edge of a door or window is smaller per metre, but there is a lot of it. One leaky casement is 88 cm², about the same as a 10 mm gap under a door — and most homes have several.

Foam tape, E, P or D profile — cheapest, fits almost anything. Self-adhesive closed-cell foam or EPDM rubber in a profile designed to squash into the gap. The 6 m D-profile draught excluder tape at about £4.49 (4.4 stars, 2,300 reviews) covers a couple of windows. Match the profile to the gap: E for 2–3.5 mm, P for 3–5 mm, D for 3–7 mm. Getting this wrong is the single most common mistake — oversized tape stops the window shutting, undersized tape does nothing.

Two things determine whether it lasts: clean the frame with methylated spirit first, not washing-up liquid, and fit it above 5°C. Tape stuck to a cold, damp frame in January will be on the floor by March.

Brush pile strip — for sliding sashes and anything that rubs. A sliding sash will shred foam tape in a season; brush pile survives it. A 5 m self-adhesive brush pile strip is around £4.94 and a 10 m brush seal about £12.99; for a garage door the heavier-duty 7 m pile seal is around £17.39.

On traditional sash windows, retrofitting brush pile into routed channels is a professional job at £100 to £200 per window, as our draught proofing cost guide sets out. Tape around the meeting rail and perimeter beading gets you a good part of the way for £5.

Do not tape over trickle vents. Those little sliders on the top of a double-glazed window are controlled ventilation, and blocking them is how a draught problem becomes a window condensation problem.

Best draught excluder for a letterbox

A letterplate is the most underrated hole in a British front door — 126 cm² of aperture, three times the gap under a typical door, sitting at chest height where the pressure difference is largest.

An internal brush-and-flap cover screws to the inside of the door and costs almost nothing: the white PVC cover with brushes and flap is about £5.89 (4.2 stars), the Stormguard PVC brush cover around £6.39, and the Merriway StormSeal in brown about £6.49 (4.4 stars). Measure the aperture, not the external plate, and check the internal clearance — some doors have a lock case in the way. One warning from the reviews: brush-only covers with no flap let wind-driven rain through on an exposed door, so pick one with both.

Best draught excluder for an unused chimney

If you have an open fireplace you never light, this is the highest-value single purchase in the guide: 28% of the leak area, and leaking harder than its share.

The Chimney Sheep is the product worth knowing about — a slab of breathable Herdwick wool felt on a handle that wedges into the throat above the fireplace and lifts out in seconds. The 12 × 20 inch size is about £48 and the 18 × 18 inch square around £50, both 4.5 to 4.6 stars; the 13 × 13 inch square suits smaller Victorian openings.

Why wool rather than an inflatable balloon: it is breathable, so the flue can still dry out — a fully sealed chimney can push damp into the breast — and it will not perish and deflate silently over a winter. Measure the throat inside the flue, not the fireplace opening, and buy slightly oversize; the felt is meant to be trimmed with scissors.

Two absolute rules. Never block a flue serving an appliance that burns anything — a gas fire, a back boiler, a wood burner, or an open fire you might light again. And leave the handle hanging into the fireplace so the next person knows it is there. At £48 buying back roughly £41 a year of gas, it pays for itself in a winter and a bit.

Best draught excluder for floorboards and skirtings

The biggest hole in the house, and the one nobody sells a product called a draught excluder for.

For a suspended timber floor, a flexible gap filler — a rubberised acrylic that flexes as the boards move — is the right material. Budget around £18 a room and a full afternoon. Rigid decorator's caulk cracks out within a year as the boards move. A bead of the same sealant where the skirting meets the floor closes a surprising amount more.

Sealing has a ceiling, though. If the cold comes up through the floor rather than between the boards, that is an uninsulated void and the answer is underfloor insulation — our floor insulation cost guide covers the cost. Do not block the airbricks below floor level; the void needs them or you will get rot.

Keyholes and cat flaps

A keyhole cover is 0.8 cm² and costs £3. Fit one because it is cheap, not because it matters. A cat flap is different: an old, ill-fitting flap is a permanently open 200 cm² hole with a piece of plastic waving about in it, and a modern magnetic or microchip flap with a brush seal is a real upgrade if yours rattles.

Where you must not seal

This is the part most product listings skip, and it matters more than any of the shopping above.

• Never reduce ventilation to an open-flued appliance. Gas fires, back boilers, older boilers with an open flue and solid fuel stoves all draw combustion air from the room. Sealing that room is a carbon monoxide risk, not an energy saving.
• Leave trickle vents and extractor fans alone. They are deliberate, controlled ventilation. Blocking them trades a draught for mould.
• Leave underfloor airbricks clear. Suspended timber floors need the void ventilated.
• If you already have damp, condensation or mould, ventilation is the priority, not sealing. Fix the moisture first.

If a gap looks deliberate and you are not sure, it probably is. A professional survey uses a smoke pencil to tell a leak from a vent, and a whole-house job is £150 to £300 — see the cost breakdown for what that includes.

Frequently Asked Questions

What is the best draught excluder for a front door?

For the gap under the door, a screw-fixed brush strip such as the Stormguard 914 mm seal at around £7.89 — it copes with an uneven threshold and lasts years, where foam and fabric do not. But on a front door the letterplate is usually the bigger hole, at 126 cm² against 42 to 84 cm², so fit a letterbox brush cover at the same time. Together they are about £14 and take twenty minutes.

Do draught excluders actually save money?

Yes, and the amount is knowable rather than a guess. Air leakage is around 20% of heat loss in an older UK home, which at the October 2026 price cap is about £147 a year of gas. Realistically you can close half to two thirds of that, giving £60 to £85 a year — the figure the Energy Saving Trust quotes. The cheap fixes have the best returns: a £4.49 roll of tape across four windows accounts for about £23 a year.

What is the best draught excluder for windows?

Self-adhesive foam or EPDM tape, matched to the gap: E profile for 2–3.5 mm, P for 3–5 mm, D for 3–7 mm. A 6 m roll is about £4.49 and does two windows. For sliding sash windows use brush pile strip instead, because a sliding sash destroys foam tape in a season. Clean the frame with methylated spirit first and fit it above 5°C, or the adhesive will fail.

Are fabric draught excluders any good?

For comfort at an internal door, yes. As a seal, no. A weighted fabric sausage blocks the cold air you feel at ankle level but does not span the full gap, moves whenever the door opens, and cannot be relied on at an external door. Use one to make a draughty hallway door tolerable, and a brush strip or flexible seal for anything that leads outside.

What is the best way to block an unused chimney?

A breathable wool chimney draught excluder such as a Chimney Sheep, around £48 to £50. It wedges into the throat, lifts out in seconds and lets the flue dry out, which an inflatable balloon does not. Never block a flue that serves any appliance burning gas, wood or solid fuel, and leave the handle visible. On leak area alone an open chimney is 28% of a typical home's draughts, so this is the single highest-value purchase here.

The bottom line

Rank by the size of the hole, not by where you feel the cold. That puts an unused chimney and bare floorboards first, then windows, the letterbox, and the door last — close to the reverse of the order most people buy in.

The genuinely cheap wins are the tape, the letterbox cover and the door brush strip: £17 for about 26% of the leak, fitted in an hour. Do them before the weather turns, because foam tape will not stick to a cold, wet frame in December.

Then turn the heating down to match. A draught-proofed home runs happily at a lower boiler flow temperature, worth another £45 to £85 a year for nothing — sealing gaps and leaving the boiler at 80°C wastes half of what you just bought. Our home insulation guide sets out where the bigger money is once the cheap jobs are done.