How to Draught-Proof Your Home and Save on Energy Bills

How to draught-proof your home

Draught-proofing is one of the cheapest energy improvements you can make to a home. It means blocking unwanted gaps that let warm air out and cold air in — and according to the Energy Saving Trust, draught-proofing your windows and doors can save £25 a year on energy bills in Great Britain (£40 in Northern Ireland). Much of it can be done in an afternoon, with materials that cost very little.

Where do draughts come from?

Draughts are unwanted cold air entering your home through gaps and cracks. The most common places are:

• Windows — gaps around frames, especially in older windows
• External doors — gaps around the edges and underneath the door
• Loft hatches — unsealed hatches let warm air escape into the loft
• Floorboards and skirting boards — gaps between boards and where they meet the wall
• Pipes — where pipes pass through walls and floors
• Unused chimneys — an open chimney is a large hole in the roof of your home

What to use for each gap

Gap	What to use
Windows	Self-adhesive foam strips or rubber seals around the frame
External doors	Brush strips or rubber seals around the frame, plus a brush excluder at the bottom
Letterboxes	A letterbox brush or flap
Keyholes	A keyhole cover
Loft hatch	Draught stripping around the hatch and insulation on top of it
Floorboards and skirting	Flexible filler or sealant
Unused chimney	A chimney balloon or chimney draught excluder — remove it before you light a fire

Most of these are available from any DIY shop, and fitting them needs no special skill: clean the surface, measure, cut and stick or screw the strip in place.

How much does it cost and save?

DIY draught-proofing materials for a typical home cost very little — usually tens of pounds. Professional draught-proofing of windows and doors for a whole house costs around £250, according to the Energy Saving Trust. The Energy Saving Trust estimates that draught-proofing windows and doors saves around £25 a year in Great Britain and £40 a year in Northern Ireland, and draught-proofing an unused chimney can save more again. The real benefit is comfort: rooms feel warmer straight away, without turning the heating up.

What you must never block

This is the part people get wrong. A home needs some air coming in, and sealing the wrong gap swaps a draught for condensation, mould or — in the worst case — a dangerous gas appliance. Never block:

• Trickle vents on windows — these are designed to let a small amount of air into rooms
• Airbricks and wall vents — these ventilate underfloor spaces and walls
• Extractor fans in kitchens and bathrooms
• Air vents for gas heaters, boilers and open fires — these appliances need air to burn safely

If your home is already fairly well draught-proofed, adding more can increase the risk of poor air quality. If in doubt, check with a professional before sealing anything you are unsure about.

Other cheap winter jobs

Draught-proofing works best alongside a few other low-cost jobs:

• Insulate your hot water tank. Topping up a tank jacket from 25mm to an 80mm British Standard jacket can save £45 a year in Great Britain, and a jacket costs around £30.
• Insulate exposed hot water pipes. Pipe insulation can save around £6 a year, and it also reduces the risk of pipes cracking or bursting if temperatures drop below freezing.
• Check your loft insulation. Upgrading an uninsulated loft to 270mm of insulation can save around £190 a year in Great Britain.
• Bleed your radiators. Trapped air stops radiators heating properly, so see our guide to bleeding your radiators and fix any cold spots.

Frequently asked questions

How much can draught-proofing save?
The Energy Saving Trust estimates that draught-proofing windows and doors saves around £25 a year in Great Britain and £40 a year in Northern Ireland.

Can I draught-proof my home myself?
Yes. Most draught-proofing — foam strips, brush excluders, letterbox brushes and filler — is simple DIY. Professional draught-proofing for a whole house costs around £250.

Should I block trickle vents to stop draughts?
No. Trickle vents are deliberate ventilation. Blocking them can cause condensation and mould, and blocking vents for gas appliances can be dangerous.

Does draught-proofing work on old windows?
Yes. Old doors and windows are usually the worst for draughts. Modern windows and doors with seals on the openings may already be draught-proofed enough.