Draught-proofing questions answered

Usually, yes. The Energy Saving Trust estimates that draught-proofing windows, doors and floors saves a typical home in Great Britain about £55 a year, and blocking an unused chimney about £45 more. Professional draught-proofing of a whole house’s windows and doors costs around £250, and doing it yourself costs less.

A home without draughts also feels warmer, so many people can turn the thermostat down a degree. Going from 22°C to 21°C saves around £120 a year.

Draught-proofing stops air moving through gaps. Insulation slows heat passing through the roof, walls and floors. Both matter: if your loft has little or no insulation, start there, then draught-proof. Finding draughts explains the difference in more detail.

Most of it, yes. Sealing doors, casement windows, letterboxes, floorboards, loft hatches and pipe holes, and fitting a removable chimney blocker, are all DIY jobs. Sash window draught-proofing, routed-in seals, fixed secondary glazing and anything involving electrics are best left to a specialist.

On a cold, windy day, run the back of your hand round doors, windows and skirtings, or hold up a strip of tissue and watch where it moves. Closing a door or window on a sheet of paper shows whether it’s sealing. Finding draughts covers every method, from a smoke pencil to a thermal camera.

A home needs some fresh air to keep condensation and mould down and to let fires and boilers burn safely. Draught-proofing seals the accidental gaps; trickle vents, air bricks, extractor fans and appliance vents should stay open. If your home has no vents of any kind, it may already be too airtight for more draught-proofing. Before you start lists what to leave open.

It is safe to block a chimney you don’t use, as long as you never block one that serves a working gas fire, boiler or stove, and you always take a removable blocker out before lighting a fire. The chimney guide sets out the safety rules.

Not if a little air can still move through it. Problems come when a chimney is sealed tight at both ends with no ventilation. Removable blockers usually let a small amount of air past, and wool lets some through by design. If you close a chimney permanently, fit a vented cap at the top and a vent at the bottom.

The Energy Saving Trust estimates about £45 a year in Great Britain. Research by the University of Liverpool, commissioned by Chimney Sheep in 2013, found a saving of about 5% of heating demand, which is around £120 a year at October 2026 gas prices. Either way, the saving applies to each unused chimney.

It depends on how the energy assessor records the chimney. Under the current EPC method, an open chimney with a damper is still counted as open, and a removable blocker may or may not be recognised. Ask your assessor before relying on one to improve a rating. A chimney permanently closed with a ventilator is recorded differently.

No. Only draught-proof doors that lead outside, or into an unheated porch, garage or conservatory. The gaps round internal doors let air move round the house, which keeps condensation down and lets appliances draw the air they need.

Yes. A specialist can fit brush or rubber seals into the sashes and beads so the window still slides but stops most of the draught. Research cited by Historic England found draught-proofing can cut air leakage through a window by a third to a half. The window guide covers DIY options too.

Try repair and draught-proofing first. Historic England found that more than three-quarters of the heat lost through a traditional window goes through the gaps, not the glass. Draught-proofing plus secondary glazing, shutters or good curtains can make a big difference for much less than replacement, and keeps original windows.

No. Trickle vents give a room a steady supply of fresh air and help prevent condensation. Seal the gaps round the opening parts of the window instead.

Only seals that don’t stop the door closing fully on its own. Never paint over, cover or remove the intumescent strips round a fire door’s edge. In a block of flats, check with the landlord or building manager before changing the front door. The door guide has more.

If you have any fuel-burning appliance, such as a boiler, gas fire, wood stove or open fire, you should have a working carbon monoxide alarm in that room. In England, landlords must fit one in every room used as living accommodation that has a fixed combustion appliance, apart from gas cookers.

Often not, but it depends on the work. Removable measures and surface-fixed seals don’t usually alter the building. Routed-in seals, fixed secondary glazing, new glazing, and changes to chimneys may need listed building consent, and doing that work without consent is a criminal offence. Speak to your council’s conservation officer first. The window guide and For professionals page have more detail.

Yes. Older solid walls let moisture pass through and dry out. Use materials that let them breathe, such as lime mortar or sheep’s wool, to fill gaps in walls, rather than cement or expanding foam. Draught-proofing doors, windows and floors is fine.

Removable measures, such as fabric excluders, curtains, removable chimney blockers and letterbox brushes, are usually fine without asking. Anything fixed, or anything that means drilling, cutting or electrics, needs your landlord’s agreement. Privately rented homes in England must reach EPC band C by 2030.

In England, the Warm Homes: Local Grant can pay for draught-proofing, insulation and heating for households with an income of £36,000 or less in homes rated EPC D to G, through participating councils. ECO4 closes on 31 December 2026. In Scotland, Wales and Northern Ireland, contact Home Energy Scotland, Nest or NISEP. Saving energy has the details.

The site is run by Chimney Sheep, a Workington-based company that makes draught excluders, including the Chimney Sheep and the Chimney Balloon. Our guides describe types of product rather than brands, and our own products only appear where they’re relevant, alongside others. About this site explains how we keep the advice fair.