Cavity wall insulation

Cavity wall Insulation

/ posted in Green Deal, Green Living, Green Tips, Home, Home energy saving tips / 5 Comments

Our quick Q & A could help you stay warm and save money

According to government estimates there are at least 5.8 million homes in the UK that still need cavity wall insulation*. And if your home is one of them, you could make valuable savings by reducing all that lovely, cosy, expensive warmth that disappears through your walls. You may have heard of a flagship government initiative called the Green Deal, and here’s a simple Q & A that could put you on the path to warmer winters and smaller bills:

Q. So what’s a cavity wall?
A. A cavity wall is actually two walls, with a gap in between them known as the cavity.

Q. And how do I know if my home has a cavity wall?
A. If your home was built from the 1920s onwards, chances are it has cavity walls. Though if it was built in the last 20 years or so the cavity is probably already insulated. If your home is brick-built, take a look at the pattern of the bricks. With a cavity wall, bricks will usually have a regular pattern. Solid walls are more likely to be in an alternating pattern.

Q. How much heat do I lose through my walls?
A. If your house is uninsulated, around a third of the heat you lose goes through your walls.**

Q. And how much is that costing me?
A. On average, you could save around £140 a year just by insulating your walls.**

Q. What will cavity wall insulation cost?
A. Based on a gas-heated, semi-detached 3 bedroom home, installation is likely to cost around £450 to £500.** So you should make your money back within the next four years. You may qualify for free cavity wall insulation if you’re eligible,*** or you could pay for cavity wall insulation under the Green Deal.

Q. What if my walls are damp, can I still go ahead?
A. If there’s damp on your inside walls, don’t insulate until that problem is fixed. Talk to a recommended builder who specialises in damp prevention.

Q. How long will the job take, and how much mess will there be?
A. On an average house with easily accessible walls, a registered installer can do the job in around two hours, with no mess at all.

Q. Who can I trust to do the job?
A.Your installer should be a member of one of these organisations:

You should also check that:

  • Your installer is signed up to a code of professional practice like the one provided by the NIA
  • The installation is guaranteed for 25 years by CIGA

Q. And will I have done my bit for the environment?
A. You certainly will. The Energy Saving Trust estimates that insulating an average UK home makes a carbon saving of around 560kg a year. So it’s worth doing in so many ways.

The good news is that npower may be able to help you save energy and money. You could even qualify for free cavity wall insulation if you are in receipt of certain benefits. Or you could qualify for other home improvements from npower, such as a new boiler or loft insulation. You can also qualify if you live in a specified postcode (defined by the government) or have a house that is difficult to insulate and keep warm.

Plus, even if you don’t qualify for free improvements, the Green Deal gives you the opportunity to make energy saving improvements to your home without paying for the work up front. To register your interest and to find out more about these schemes, just visit

***Check your eligibility here

Comments on this article (5)

Thiago | commented on 12.02.14

Great Q&A, that was immensely helpful. We're planning on redoing our wall insulation as soon as the weather warms up a little bit more, so this was a perfect fine. Thanks for sharing your expertise!

Mr james Howgate | commented on 25.02.14

I have your leaflet on free energy saving wall insulation to hand, I would like to know if it is at all possible to insulate my walls, when I bought my house the previous owner said that the walls were block built cavity type, is there any help available for me, I am 77 this November and receiving DLA and pension credit so would I benefit with free insulation if it was possible to do my walls, I live in a open area with Westerly and most important Easterly winds right on the perimeter of the beach almost, we have a great deal of bad weather here in the winter months, the house is very cold upstairs although we have an old aga going continuously, we have a boiler with three radiators but cannot afford to run it what with the price of oil and running the aga as well, hoping that you can help somehow. I am yours respectfully, Mr James Howgate.

    Emily Ward | commented on 27.02.14

    Hi Mr Howgate, Thank you for your comment and query about wall insulation. If you'd be happy to pass on your contact details, I will arrange for a colleague in our Green Deal/ECO team to contact you to discuss your property and options in more detail. Please send your telephone details and postcode to (also please confirm if you are an existing npower customer or not). Many thanks, Emily

HOLISTIC HEALTH | commented on 23.11.16

After I originally left a comment I seem to have clicked the -Notify me when new comments are added- checkbox and from now on whenever a comment is added I receive four emails with the same comment. There has to be a way you can remove me from that service? Many thanks!

    Cassie Oliver | commented on 02.12.16

    Hi– there should be an unsubscribe button on the bottom of the emails we send to you, please click this to remove yourself from the mailing list. Many thanks, Cassie

Add a comment



Our Social Sites