Draught proofing

Draught-proofing is one of the cheapest and most effective ways to save energy – and money – in any type of building.

Controlled ventilation helps reduce condensation and damp, by letting fresh air in when needed.

However, draughts are uncontrolled: they let in too much cold air and waste too much heat.

To draught-proof your home, you should block up unwanted gaps that let cold air in and warm air out.

Saving warm air means you’ll use less energy to heat your home, so you’ll save money as well as making your home snug and warm.

How much could you save by draught-proofing?

Draught-proofing around windows and doors could save you around £45 a year*.

If you have an open chimney, draught-proofing your chimney when you’re not using it could save around £65 a year*.

Draught-free homes are comfortable at lower temperatures – so you may be able to turn down your thermostat, saving even more on your energy bills.

* Savings based on a typical gas-fuelled semi-detached property in England, Scotland or Wales.

DIY or professional?

Draught-proofing costs will vary depending on how much and which areas of your home you want to draught-proof.

Professional draught-proofing could cost around £225 for your whole house*. DIY draught-proofing will be cheaper.

*Based on a typical semi-detached property in England, Scotland or Wales.

If you’re happy carrying out simple DIY tasks, draught-proofing will be no problem.

However, some homes, especially older homes with single glazing, will be more difficult to draught-proof.

Professional draught-proofing is likely to save more energy because the installer will know exactly the right materials to use and where to use them.


Air needs to flow in and out of your house so it stays fresh, dry and healthy.

Make sure you don’t block or seal any intentional ventilation, including:

  • Extractor fans – these take out damp air quickly in rooms where lots of moisture is produced (for example, kitchens, bathrooms and utility rooms).
  • Underfloor grilles or airbricks – these help keep wooden beams and floors dry.
  • Wall vents – which let small amounts of fresh air into rooms.
  • Trickle vents – modern windows often have small vents above them to let fresh air trickle in.

Dealing with draughts

Draughts happen where there are unwanted gaps in the construction of your home, and where openings are left uncovered.

You’ll find draughts at any accidental gap in your home that leads outside.

You should block most of these – but be careful in areas that need good ventilation, such as:

  • Areas where there are open fires or open flues.
  • Rooms where a lot of moisture is produced, such as the kitchen, bathrooms and utility rooms.

These are the most common areas to find draughts, with suggestions on how to fix them.


For windows that open, buy draught-proofing strips to stick around the window frame and fill the gap between the window and the frame. There are two types:

  • Self-adhesive foam strips – these are cheap and easy to install, but may not last long.
  • Metal or plastic strips with brushes or wipers attached, which are long-lasting, but cost a little more.

Make sure the strip is the right size to fill the gap in your window.

If the strip is too big, it will get crushed and you may not be able to close the window. If it’s too small, there will still be a gap.

For sliding sash windows, foam strips do not work well.

It’s best to fit brush strips or consult a professional. For windows that don’t open, use a silicone sealant.

If you’re thinking of replacing your windows, consider installing energy efficient windows.


Draught-proofing external doors can stop a lot of heat from escaping, and won’t cost you much.

There are four main areas to consider draught-proofing:

  • Keyhole – buy a purpose-made cover that drops a metal disc over the keyhole.
  • Letterbox – use a letterbox flap or brush, but remember to measure your letterbox before you buy.
  • Gap at the bottom – use a brush or hinged flap draught excluder.
  • Gaps around the edges – fit foam, brush or wiper strips like those used for windows.

Internal doors need draught-proofing if they lead to a room you don’t normally heat, such as your spare room or kitchen.

Keep those doors closed to stop the cold air from moving into the rest of the house.

If there is a gap at the bottom of the door, block it with a draught excluder – you can make one stuffed with used plastic bags or bits of spare material.

Internal doors between two heated rooms don’t need draught-proofing, as you don’t lose energy when warm air circulates.


If you don’t use your fireplace, your chimney is probably a source of unnecessary draughts.

There are two main ways to draught-proof a chimney:

  • Fit a cap over the chimney pot – this might be better done by a professional.
  • Buy a chimney draught excluder – these help stop draughts and heat loss through the chimney, and are usually fitted inside the chimney or around the fireplace.

Remember to remove the draught-proofing if you decide to light a fire.

Find out more about draught-proofing your chimney.

Floorboards and skirting boards

You can block cracks in your floor by squirting filler into the gaps.

Floorboards and skirting boards often contract, expand or move slightly with everyday use, so you should use a filler that can tolerate movement – these are usually silicone-based.

Look for the following products:

  • flexible fillers
  • decorator’s caulk
  • mastic-type products

Fillers come in different colours, and for indoor and outdoor use.

They block gaps permanently so be careful when you apply them – wipe off any excess with a damp cloth before it dries.

Fillers may break down over time, but can easily be reapplied.

Check whether you also need to insulate between the skirting board and the floor.

Find out more in our guide to floor insulation.

Loft hatches

Hot air rises and gets lost in the cold space in your loft or attic, so it’s worth blocking off draughts around your loft hatch.

Use strip insulation, as you would on a door.

You can read more in our guide to insulating your loft and roof space.


You can fill small gaps around pipework with silicone fillers, similar to the fillers used for skirting boards and floorboards.

Fill larger gaps with expanding polyurethane foam.

This is sprayed into the gap, expands as it dries, and sets hard.

We have more information about insulating tanks, pipework and radiators.

Old extractor fans

Old fan outlets may need to be filled with bricks or concrete blocks and sealed from both the inside and outside.

Cracks in walls

You can fill in cracks using cements or hard-setting fillers.

These will work around electrical fittings on walls and ceilings and at ceiling-to-wall joists.

If there is a large crack in your wall, you may need to check if there’s an underlying problem.

Consider consulting a surveyor or builder to see what caused the crack in the first place.

SOURCE: energysavingtrust.org.uk

Dave Stroud
Author: Dave Stroud