Hearth & Lawn

Cheap draught-proofing fixes that cut heat loss

Last updated: · By the Hearth & Lawn team

How we chose these: We haven't tested these products ourselves. This guide is based on Energy Saving Trust advice and savings estimates, UK retailer listings (mainly Screwfix and Wickes) and owner reviews. Prices were checked on 18 October 2026.

Draughts are the cheapest heat loss to fix. A brush strip on the front door, a letterbox flap, some foam strips round a rattly window and a removable chimney excluder can cost well under £50 in total.

The Energy Saving Trust estimates that draught-proofing windows, doors and floors could save around £55 a year in Great Britain. Draught-proofing an unused open chimney could save around £45 a year. It also points out that a draught-free home feels comfortable at a lower temperature. Turning the thermostat down from 22°C to 21°C could save another £120 a year.

But don't seal everything. Your home needs controlled ventilation to stay dry and safe. Blocking the wrong vent can cause condensation and mould, or worse, carbon monoxide build-up from a gas appliance. The safety section below covers what to leave alone.

Quick picks

Fix What we'd buy Price checked 18 Oct 2026 Energy Saving Trust saving
Gap under the front or back door Stormguard Bottom Door Brush Draught Excluder, 1m £6.78 at Screwfix Part of about £55/year for doors, windows and floors
Letterbox Stormguard Brush Letter Plate Draught Excluder, 338 × 75mm £7.49 at Screwfix (as above)
Gaps around opening windows and doors Stormguard Self-Adhesive Brush Pile Weatherstrips, 3 × 5m £13.99 at Screwfix (as above)
Cheap foam alternative Stormguard Extra Thick Weatherstrips, 2 × 3.5m £7.06 at Screwfix (as above)
Unused open fireplace Stormguard Chimney Inflatable Draught Excluder, 700mm £16.99 at Screwfix About £45/year
Reusable chimney option Chimney Sheep, oblong 14″ × 24″ £52.50 at Chimney Sheep About £45/year
Radiators on uninsulated outside walls SuperFOIL Radiator Heat Reflector Foil, 600mm × 5m £19 at Screwfix About £18/year
Single-glazed or draughty windows (temporary) Wickes Seasonal Secondary Glazing Film, 6m² £6.50 at Wickes No EST estimate

What it's worth

The Energy Saving Trust's figures are typical savings, not guarantees. Your saving depends on how draughty your home is to start with. As a rough check, if you heat with gas: £55 a year at the gas price cap of 7.97p per kWh works out at about 55 ÷ 0.0797 = 690kWh of gas a year you'd no longer need to burn.

A basic DIY kit for one external door and a couple of windows costs about £28 from the list above: door brush £6.78, letterbox brush £7.49 and two packs of foam strips at £7.06 each. Against a saving of that size, it can pay for itself in the first winter in a draughty home. In a home that's already fairly airtight, the saving will be smaller. The Energy Saving Trust says a home with no trickle vents, wall vents or mechanical ventilation may already be too airtight for draught-proofing.

The Energy Saving Trust puts professional draught-proofing of windows and doors at around £250 for a whole house. That's worth considering for older homes, sash windows and anything you're not confident tackling yourself.

Fix by fix

1. Doors: brush strips and letterbox flaps

The Energy Saving Trust suggests four areas on an outside door: the keyhole (a cover that drops over it), the letterbox (a brush or flap), the gap at the bottom (a brush or hinged flap excluder), and gaps around the edges (foam, brush or wiper strips).

Stormguard Bottom Door Brush Draught Excluder, 1m: £6.78 at Screwfix. Screw it to the bottom of the door so the brush just touches the floor. Brushes cope with uneven floors and doormats better than rigid rubber seals.

Stormguard Brush Letter Plate Draught Excluder, 338 × 75mm: £7.49 at Screwfix. It fits on the inside of the door over the letterbox opening. Measure your letterbox before you buy.

Fabric "sausage" excluders are fine for a door you rarely open. They're easy to trip over and get kicked aside, so a fixed brush is better for a door you use every day.

Don't draught-proof internal doors. The Energy Saving Trust says there should be a gap under internal doors so air can move around the home.

2. Windows: strips, sealant and film

For windows that open, the Energy Saving Trust recommends strips that fill the gap between window and frame:

  • Self-adhesive foam strips are cheap and easy to fit, but may not last long. Stormguard Extra Thick Weatherstrips, 2 × 3.5m: £7.06 at Screwfix.
  • Brush or wiper strips last longer and cost a little more. Stormguard Self-Adhesive Brush Pile Weatherstrips, 3 × 5m: £13.99 at Screwfix. Brush strips are the type to use on sliding sash windows, where foam doesn't work well.

Get the size right: too thick and the window won't shut; too thin and the draught still gets through. For windows that never open, the Energy Saving Trust suggests silicone sealant.

Window insulation film is a clear plastic sheet you tape to the frame and shrink tight with a hairdryer. It works like temporary secondary glazing. Wickes Seasonal Secondary Glazing Film, 6m²: £6.50 at Wickes. Stormguard's 6m² kit was listed at £10 at Dunelm but out of stock when we checked. It's most useful on single glazing in a rented home, where you can't change the windows. You can't open the window while the film is on, so don't film over windows you need for ventilation or as a fire escape route.

3. Chimneys: removable excluders

If you never use an open fireplace, warm air goes straight up the chimney. The Energy Saving Trust suggests a chimney draught excluder fitted inside the chimney or around the fireplace. It says this shouldn't fully block the chimney so some ventilation remains, and that you must remove it before lighting a fire.

  • Stormguard Chimney Inflatable Draught Excluder, 700mm: £16.99 at Screwfix, in stock. An inflatable "chimney balloon" you push up into the flue and inflate.
  • Chimney Sheep oblong 14″ × 24″ (36 × 61cm): £52.50 at Chimney Sheep. A felted wool plug that you push up into the flue. Smaller sizes are cheaper. Measure the throat of your chimney first.

Our own advice on top: don't fit a chimney excluder in a fireplace that has a gas fire, stove or any other appliance connected to the flue. Leave a visible reminder on the hearth so nobody lights a fire with it in place.

4. Radiator reflector foil: only on outside walls

The Energy Saving Trust says radiator reflector panels do work, but mainly behind radiators on uninsulated external walls. There, it estimates a saving of about £18 a year. On internal walls, the heat stays in the house anyway, so they're not worth it. Kitchen foil isn't a substitute: it's hard to keep in place and doesn't do the same job.

  • SuperFOIL Radiator Heat Reflector Foil, 600mm × 5m: £19 at Screwfix.
  • A cheaper roll, Essentials Radiator Heat Reflector Foil, 470mm × 4m, was £6.39 at Screwfix.

If your home has cavity wall or solid wall insulation, skip this one.

5. Thermal curtains and blinds

Heavy or thermal-lined curtains help, especially on single-glazed or older double-glazed windows. Close them at dusk and tuck them behind radiators rather than draping them over the top, so the heat goes into the room. Thermal-lined pairs at John Lewis started at about £80–£90 when we checked. Independent figures on how much they save are hard to find, so we haven't put a number on it.

What you must never block

These come straight from Energy Saving Trust guidance:

  • Extractor fans in kitchens, bathrooms and utility rooms.
  • Underfloor grilles and airbricks, which keep wooden floors and joists dry.
  • Wall vents.
  • Trickle vents above windows. Leave them open all the time.
  • Fixed ventilation for gas appliances. All flueless gas appliances, such as some gas hobs and fires, need ventilation to work safely. Never block fixed ventilation openings for flueless or open-flue gas heaters.
  • Rooms with open fires or open flues, and rooms that make a lot of moisture, such as kitchens and bathrooms.

The Energy Saving Trust also says that if your home has no trickle vents, wall vents or mechanical ventilation, it may already be too airtight, and draught-proofing may not be suitable.

If you have any appliance that burns gas, oil, coal or wood, the NHS recommends a carbon monoxide alarm in each room that has one. It also recommends getting them serviced regularly by a qualified, registered engineer.

If you notice more condensation after draught-proofing, ventilate more, not less. See our condensation and black mould guide.

If you rent

Most of these fixes are removable: brush strips can be unscrewed, foam strips peeled off, film taken down in spring and a chimney balloon deflated. Ask your landlord before drilling or fitting anything permanent. Badly fitting windows and doors may be a repair your landlord is responsible for; Shelter and Citizens Advice can tell you where you stand.

Grants and bigger jobs

The Energy Saving Trust notes that the government's Warm Homes Plan includes fully funded draught-proofing for people on low incomes, plus low- and zero-interest loans for homeowners. Details were still being confirmed when we checked. GOV.UK's "Find energy grants for your home" service is the place to start. For professional draught-proofing, the Energy Saving Trust suggests getting three quotes and using TrustMark, the government-endorsed quality scheme, to find an installer.

FAQs

What is the best draught excluder for doors? For a door you use every day, a brush strip screwed to the bottom of the door, such as the Stormguard 1m brush at £6.78. Fabric sausage excluders are fine for doors you rarely open.

Do radiator reflectors work? Yes, but only really behind radiators on uninsulated outside walls, where the Energy Saving Trust estimates a saving of about £18 a year. On internal walls they're not worth fitting.

Are chimney balloons safe? They're designed for fireplaces you don't use. The Energy Saving Trust says a chimney excluder shouldn't fully block the chimney, and that you must remove it before lighting a fire. We'd also never fit one where a gas fire or any other appliance uses the flue.

Does window insulation film work? It acts as temporary secondary glazing and cuts draughts through single-glazed or badly fitting windows. You can't open the window while the film is on, so leave at least one window per room you can open for ventilation.

Can draught-proofing cause damp? It can if you block ventilation. Never block trickle vents, airbricks, extractor fans or gas appliance vents. Draught-proofing stops uncontrolled draughts; controlled ventilation still needs to work.

How much does draught-proofing save? The Energy Saving Trust estimates around £55 a year in Great Britain for windows, doors and floors, and about £45 a year for an unused chimney. Your saving depends on how draughty your home is to start with.

Sources