How are cavity walls insulated?

To insulate your cavity walls, the installer drills small holes around 22mm in size at intervals of around 1m - 1.5m from the outside of your home. With specially designed equipment, they then blow insulation into the cavity.

Once all the insulation is in, the installer fills the holes in the brickwork with matching mortar so you'll barely notice them.

How do you find a registered installer?

You can call your local Energy Saving Trust advice centre (add link to relevant page) for free on 0800 512 012. Our advisors there will be happy to help you find a registered installer.

We consider a registered installer for cavity wall insulation being one that is a member of any one of the following organisations and you can find a list of their registered installers on their websites:

Two key things to look out for when considering an installer:

They sign up to a code of professional practice like those provided by the NIA
The installation is guaranteed for 25 years by CIGA.

What is cavity wall insulation made of?

Cavity wall insulation can be made out of three types of materials:

Mineral wool
Beads or granules
Foamed insulants

All three are manufactured according to British standards. Foam Insulation systems should be certified by the British Board of Agrément (BBA) and installed according to strict guidance laid out in the associated BBA Certificates

What type of cavity wall insulation is used?

Your installer will know the most suitable type of insulation for you but ask if they are using Energy Saving Recommended insulation, this means it complies to British standards and it has a 25 year guarantee.

Grants and offers

To help with the cost of installation there are a range of grants and offers available from the government, local authorities and energy suppliers.

You can take up grants and offers from any of the energy companies, regardless of who supplies your gas and electricity. Most energy suppliers provide grants for cavity wall insulation for free to those aged over 70 or those in receipt of certain benefits.

To find out whether you are entitled to a grant, call your local Energy Saving Trust advice centre on 0800 512 012 for free, impartial advice. Our advisors will tell you about any special grants or offers available in your area - and whether you can apply for them.

Details of grants and offers can also be found on our grants and offers database too.

Tax allowances for private landlords

Tax allowances of up to £1,500 are available until 2015 for Landlords through the Landlords Energy Saving Allowance. This allowance can be used on each of the properties a landlord owns, enabling landlords to claim the costs for cavity wall insulation, loft insulation, solid wall insulation, draught proofing, hot water tank insulation and floor insulation. Visit the HM Revenue & Customs website for more information.