A letterbox draught fix costs £5–£40 in materials and can save around £20–£30 a year on heating bills
Draughty letterboxes are a common source of heat loss in UK homes, letting cold air in and warm air out. The Energy Saving Trust estimates that draught-proofing the whole home can save up to £125 a year, with letterbox-specific savings typically accounting for a £20–£30 reduction in annual heating bills (Energy Saving Trust, 2026). The most common DIY fix is a brush-strip letterbox flap or cover, priced between £5 and £15 from hardware retailers or online marketplaces. A fitted internal letterbox draught excluder (a padded flap that hangs inside the door) costs £15–£40.
A letterbox draught fix costs £5–£40 in materials and can save £20–£30 a year on heating bills. The most common DIY option is a brush-strip flap fitted in under 30 minutes.
- A brush-strip flap costs £5–£15 and pays back in 2–6 months.
- Annual savings from a letterbox draught fix range £20–£30.
- Internal padded flaps cost £15–£40 and suit older doors.
- Complete replacement letterboxes with seals cost £25–£60.
- Fit a brush strip in under 30 minutes with no specialist tools.
- A letterbox draught fix costs £5–£40 in materials and can save around £20–£30 a year on heating bills
- Quick numbers — typical costs, savings, and payback for common letterbox draught fixes
- A brush-strip letterbox flap is the most common DIY fix and can be fitted in under 30 minutes
- An internal padded letterbox draught excluder is the most effective option for older or ill-fitting letterboxes
- Replacing the entire letterbox with a draught-proof model is the best option for a permanent fix
- The direct answer to "letterbox draught fix" is a brush-strip flap costing £5–£15, fitted inside the door in 15–30 minutes
- For professional installation, look for a FENSA or TrustMark certified installer, or a local handyman with good reviews
- DIY fitting of a brush-strip flap is straightforward and requires no certification or specialist skills
Quick numbers — typical costs, savings, and payback for common letterbox draught fixes
| Fix type | Typical cost (materials) | Annual saving | Payback period |
|---|---|---|---|
| Brush-strip flap | £5–£15 | £20–£30 | 2–6 months |
| Internal padded flap | £15–£40 | £20–£30 | 6–16 months |
| Complete replacement letterbox with integrated brush seal | £25–£60 | £20–£30 | 10–24 months |
| Professional installation (if not DIY) | £40–£80 (labour) | £20–£30 | 16–32 months |
A brush-strip letterbox flap is the most common DIY fix and can be fitted in under 30 minutes
The brush strip attaches to the inside of the door, covering the letterbox opening with nylon bristles that block draughts while allowing post to pass through. No specialist tools are required — most kits come with adhesive backing or screws, and a screwdriver or drill is sufficient. The brush strip should be measured to match the letterbox width; standard UK letterbox openings are roughly 200–250mm wide (Energy Saving Trust draught-proofing DIY guides, 2026). This fix works on uPVC, wooden, and composite doors, provided the internal surface is clean and flat for adhesion.
An internal padded letterbox draught excluder is the most effective option for older or ill-fitting letterboxes
These are fabric pouches filled with foam or polyester wadding that hang inside the door, sealing the opening when not in use. They block both draughts and noise, and are especially useful for doors with loose or damaged letterbox flaps where a brush strip alone may not provide a full seal. However, they need to be removed before post is inserted, which some users find inconvenient. Manufacturer specifications and EST draught-proofing advice confirm their effectiveness, though no formal UK government test data for this specific product type exists (Energy Saving Trust, 2026).
Replacing the entire letterbox with a draught-proof model is the best option for a permanent fix
A new letterbox with an integrated brush seal or magnetic closure costs £25–£60 for a standard UK door (typical retail prices from UK builders’ merchants, 2026). Installation involves removing the old letterbox from the door, which may require cutting or enlarging the existing hole if the new unit is a different size. This option also improves security if the new letterbox has a locking flap or anti-fishing design. For homeowners who want a one-time solution without ongoing maintenance, this is the most durable choice.
The direct answer to “letterbox draught fix” is a brush-strip flap costing £5–£15, fitted inside the door in 15–30 minutes
This is the cheapest, fastest, and most widely available solution for sealing a standard letterbox. It works on uPVC, wooden, and composite doors, provided the internal surface is clean and flat for adhesion. The fix reduces heat loss and cold draughts immediately, with a payback period of under six months in most homes (Energy Saving Trust draught-proofing guides, 2026). For the majority of UK households, this represents the best balance of cost, effort, and effectiveness.
For professional installation, look for a FENSA or TrustMark certified installer, or a local handyman with good reviews
FENSA certification is primarily for window and door installation, but many FENSA-registered fitters also offer letterbox replacements and draught-proofing (FENSA website, 2026). TrustMark is a government-endorsed quality scheme covering home improvements, including draught-proofing work (TrustMark website, 2026). If replacing the letterbox yourself, ensure the new unit meets PAS 24 security standards — the UK security standard for doors and windows — by checking the product specification (British Standards Institution, 2026). How to choose a certified home improvement installer
DIY fitting of a brush-strip flap is straightforward and requires no certification or specialist skills
The main risk is poor adhesion if the door surface is not cleaned and dried thoroughly before fitting. Measure the letterbox opening width and buy a brush strip that is slightly wider (e.g., 10mm each side) for a snug fit. For uPVC doors, use a brush strip with self-adhesive foam tape; for wooden doors, screws may provide a more secure fix (Energy Saving Trust fitting guidance, 2026). Most kits from major brands such as Stormguard, Ecohome, or DraughtEx include clear manufacturer instructions. Draught-proofing your front door step by step
Frequently Asked Questions
A DIY brush-strip flap costs £5–£15, while an internal padded excluder costs £15–£40. The Energy Saving Trust notes these fixes can save £20–£30 a year on heating bills.
For most UK homes, a brush-strip flap is the best DIY option, costing £5–£15 and fitting in under 30 minutes. For older or ill-fitting letterboxes, an internal padded excluder at £15–£40 provides a tighter seal.
Yes, a letterbox draught fix can save £20–£30 a year on heating bills according to the Energy Saving Trust. The payback period is 2–6 months for a brush-strip flap.
Yes, most brush-strip flaps are DIY-friendly and take under 30 minutes to fit with a screwdriver or drill. Kits come with adhesive backing or screws for uPVC, wooden, and composite doors.
Standard UK letterbox openings are roughly 200–250mm wide, as per the Energy Saving Trust's draught-proofing guides. Measure your opening before buying a brush-strip flap or replacement.
