Draught-proofing

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

Draughts are a bit like ventilation – both let fresh air into your home. Good ventilation helps reduce condensation and damp. But 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 pleasant.

 

How much could you save by draught-proofing?

Draught-proofing around windows and doors could save you on average between £10 to £50 per year. Draught-free homes are comfortable at lower temperatures – so you’ll be able to turn down your thermostat. This could save you another 10% off your heating bill.

 

Where to look for 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, such as:

  • windows
  • doors – including keyholes and letterboxes
  • loft hatches
  • electrical fittings on walls and ceilings
  • suspended floorboards
  • pipework leading outside
  • ceiling-to-wall joints.

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

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

DIY or professional?

  • DIY draught-proofing typically costs around £100 for materials.
  • Professional draught-proofing might cost double this.

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 – it might be worth asking a professional. 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.

 

Choosing the right draught-proofing materials

There are plenty of DIY stores that sell draught-proofing materials, but look for draught-proofing with the Kitemark – this shows that the product is made to a good standard. British Standard Institution accredited products have a 20-year life if properly installed and maintained.

 

Windows

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 – cheap, and easy to install, but may not last long
  • metal or plastic strips with brushes or wipers attached – 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 silicon sealant.

 

Doors

Draught-proofing outside doors can save a lot of heat and will only cost you a few pounds. There are four main things to think about:

  • the keyhole – buy a purpose-made cover that drops a metal disc over the keyhole
  • the letterbox – use a letterbox flap or letterbox brush, but remember to measure your letterbox before you buy
  • the 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.

Inside 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.

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

 

Chimneys and fireplaces

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 – devices that help stop draughts and heat loss through the chimney, usually fitted within the chimney or around the fireplace.

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

 

Floorboards and skirting boards

You can block cracks using filler that you squirt into the gap. 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 silicon-based. Look for:

  • 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 and wipe off any excess with a damp cloth before it dries. They may break down over time, but can easily be re-applied.

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

 

Loft hatches

Hot air rises and gets lost into 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.

 

Pipework

You can fill small gaps around pipework with silicon 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.

 

Old extractor fans

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

 

Cracks in walls

You can fill in cracks using cements or hard setting fillers – but if it’s a large crack, there may be something wrong with your wall. Consult a surveyor or builder to see what caused the crack in the first place.

 

Ventilation

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:

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

Draught-proofing products and installers

For a list of registered installers whose work is guaranteed for ten years, see the National Insulation Association website.

For products, installers and manufacturers see the Draught Proofing Advisory Association.

 

Help for landlords

Until April 2015, the Landlord’s Energy Saving Allowance lets you claim up to £1,500 against tax for energy-saving improvements you have made to each house or flat you rent out. Find out more at the Directgov website.

 

Save money!

You’ll be charged a lower rate of VAT when you have energy-saving work done to your house, both for the materials and equipment, and for the labour. If the house is new, you pay no VAT at all. Find out more at the HMRC website.

 

Planning a home improvement project?