Draught-proofing is the single cheapest way to reduce your heating bill by up to 10%
Draught-proofing is the fastest and most affordable way to cut your heating costs. The Energy Saving Trust says a typical semi-detached home can save £30–£60 per year by sealing the main gaps and cracks (Energy Saving Trust, 2026).
Materials cost as little as £5–£15 per window or door, and most DIY installations take under 30 minutes. Unlike insulation or a new boiler, draught-proofing has an immediate payback with no specialist tools or certification needed. The Energy Saving Trust estimates that a typical semi-detached home loses up to 20% of its heat through gaps and cracks that draught-proofing can seal (Energy Saving Trust, 2026).
The three highest-return draught-proofing jobs you can do this weekend
These three tasks give the best return on your time and money. You can complete all of them in a single weekend.
Sealing the letterbox with a brush flap. A letterbox brush costs £5–£10 and saves £10–£15 per year (Energy Saving Trust, 2026). The payback is under one heating season.
Adding self-adhesive foam strips to window frames. Foam strips cost £8–£15 per window and save £15–£25 per year per window (Energy Saving Trust, 2026). Measure the gap before buying to get the right thickness.
Fitting a door sweep or threshold seal on the front door. A door sweep costs £10–£20 and saves £15–£20 per year (Energy Saving Trust, 2026). This is the single most effective fix for a draughty front door.
Chimney draught excluder. A chimney balloon or cap costs £15–£25 and saves £20–£30 per year if the fireplace is unused (Energy Saving Trust, 2026). Remove the balloon before lighting a fire.
Quick numbers cost, saving, and payback for common draught-proofing fixes
| Job | Typical material cost | DIY labour time | Annual energy saving | Payback period | Difficulty |
|---|---|---|---|---|---|
| DIY foam window strips | £8–£15 per window | 10 minutes per window | £15–£25 per window | 6–10 months | Easy |
| Letterbox brush | £5–£10 | 5 minutes | £10–£15 | 4–8 months | Easy |
| Door sweep or threshold seal | £10–£20 | 15 minutes | £15–£20 | 6–12 months | Easy |
| Chimney balloon | £15–£25 | 5 minutes | £20–£30 | 6–10 months | Easy |
| Keyhole cover | £2–£5 | 1 minute | £2–£5 | 1–2 months | Easy |
| Pipe gap filler (expanding foam) | £5–£8 per tube | 10 minutes per gap | £5–£10 per gap | 6–12 months | Easy |
All figures from the Energy Saving Trust draught-proofing page (Energy Saving Trust, 2026).
What draught-proofing actually saves on your annual energy bill
The Energy Saving Trust calculates that a typical semi-detached home can save £60–£100 per year by draught-proofing all main gaps (Energy Saving Trust, 2026). Savings scale with home size. Terraced homes save £30–£50 per year. Detached homes save £80–£130 per year (Energy Saving Trust, 2026).
Combined with turning down the thermostat by 1°C, savings can reach £100–£150 per year (Energy Saving Trust, 2026). Draught-proofing reduces heat loss by up to 20%. This means your boiler runs less and uses less gas or oil.
These savings are real and repeatable. They do not require you to change your heating habits or buy new equipment.
How to check which gaps are costing you money without buying any kit
You do not need to buy anything to find the draughts in your home. Use a lit incense stick or candle on a still day. Movement of the flame shows a draught, even if you cannot feel it with your hand.
Check around window frames, door edges, letterboxes, keyholes, pipe entries, loft hatches, and floorboards (Energy Saving Trust, 2026). Look for visible light gaps under doors or around windows. If you can see daylight, you have a draught.
The Energy Saving Trust recommends checking at night with a torch from outside while someone inside looks for light leaks. This method reveals gaps that are invisible during the day.
The payback maths why cheap wins beat expensive insulation on speed of return
A £10 letterbox brush pays for itself in under one heating season (6–8 months) based on a £15 annual saving. Foam window strips at £12 per window pay back in 6–10 months (Energy Saving Trust, 2026).
By contrast, loft insulation costing £300–£500 takes 2–4 years to pay back. Cavity wall insulation costing £500–£800 takes 3–5 years (Energy Saving Trust, 2026).
Draught-proofing is the only energy-saving measure with a sub-12-month payback for most homes (DESNZ, 2026). If you want to see a return on your money this winter, start with draught-proofing.
How to verify your draught-proofing installer if you do not DIY
If you prefer to hire someone, check their credentials first. For professional draught-proofing of windows and doors, the installer should be registered with FENSA or CERTASS (GOV.UK, 2026).
For draught-proofing as part of a larger energy-efficiency package, such as with insulation, the installer should hold MCS certification (MCS, 2026). TrustMark is the government-endorsed quality scheme for all home improvements, including draught-proofing (TrustMark, 2026).
Always ask for a written quote and check the installer’s public liability insurance before work begins.
How to draught-proof a Victorian terrace without damaging original features
The one gap homeowners forget that costs £20–£30 per year
The gap between floorboards and skirting boards is often overlooked. In older homes with suspended timber floors, this gap can lose significant heat.
A tube of flexible filler or silicone sealant costs £5–£8 and can seal 10–15 metres of skirting gap. The Energy Saving Trust estimates that unsealed floorboards can increase heating bills by 5–10% in homes with suspended timber floors (Energy Saving Trust, 2026).
For large gaps under skirting boards, use a foam backer rod before sealing with caulk. Total cost is under £15 for a typical room. This fix is often missed because the gap is at floor level and not visible from standing height.
How to insulate suspended timber floors without lifting floorboards
