Cavity wall insulation
Insulation can help you make big savings on your energy bills.
And insulating the walls of your home can cut your ene rgy costs by just as much as insulating your roof.
Mind the gap!
Many homes in the UK have so-called cavity walls made of two separate layers with a gap - or cavity - between them.
The cavity is designed to stop rainwater from soaking through to the inside of the property, but it also allows a lot of heat to escape.
By plugging the gap with insulation, you can therefore keep the heat in and spend less on energy.
How much could I save?
The amount of money you could save by installing cavity wall insulation depends on the size of your house.
If your home is a detached house, the Energy Saving Trust estimates that you could save £250 a year. But if you live in a flat, your annual savings will be more like £75.
Installing cavity wall insulation for a flat is also cheaper. The average cost is £330, versus £720 for a detached house.
That said, not every flat is suitable for cavity wall insulation. And even if it's practicable, there may be hurdles to surmount regarding shared tenancy and landlord involvement.
Does my home have cavity walls?
Most properties built after 1920 have cavity walls - with most of those built in the last 15 years or so having insulation fitted in the original specification.
To find out for sure whether cavity wall insulation is for you, contact your local authority or ask a registered installer to check by drilling a small hole in an external wall.
Cavity wall insulation cannot be fitted to all homes with cavity walls. If, for example, the cavity is less than 50mm wide, insulation will not be effective.
The brickwork or masonry also needs to be in good condition and the walls should not be exposed to driving rain.
And if there are any damp problems in the house, they should be fixed first.
How insulation works
You cannot fit cavity wall insulation yourself, it must be done by a registered installer.
The installer will drill small holes into the external wall then blow the insulation into the holes using special equipment before refilling them.
The cavity wall insulation will be made of mineral wool, granules or foam. And the whole process should only take about three hours!
How to find an installer
It is vital that the person who installs your cavity wall insulation is a member of one of three professional organisations: National Insulation Association (NIA), Cavity Insulation Guarantee Agency (CIGA), or British Board of Agrément (BBA).
Check too that they have signed up to a code of practice and that the installation is guaranteed for 25 years by CIGA.
If you are a tenant, you cannot carry out any work on the property without the permission of the landlord. You need to contact the landlord first and get his or her agreement if you want to insulate the walls.
You may be eligible for discounted or free insulation under the terms of the Energy Company Obligation, which is funded by the 'Big Six' energy companies.
For those on lower incomes and benefits, there are also Government schemes available - linked to the Green Deal.
You can find out more about the Green Deal here or by calling the Energy Saving Trust on 0300 123 1234 (or 0808 808 2282 in Scotland).
The Energy Saving Trust can help you arrange a Green Deal Assessment, as well as giving you more information about the Energy Company Obligation.
†10% of customers could save up to £670. MoneySuperMarket Data, May 2016