External Wall Insulation

Insulating your solid walls could cut your heating costs considerably, because solid walls let through twice as much heat as cavity walls do. The good news is they can be insulated.

If your home was built before 1919, its external walls are probably solid rather than cavity walls. Cavity walls are made of two layers with a small gap or ‘cavity’ between them. Solid walls have no gap, so they let more heat through.

Another way to tell is by measuring the width of the wall. Look at an external wall window or door and if the brick wall is less than 260mm, then it is likely a solid wall, while if it is greater, it is probably a cavity wall.

If you live in a house that is not made from bricks, such as a steel or timber-framed building, insulating will be different.

Solid wall insulation

Solid walls can be insulated – either from the inside or the outside. This will cost more than insulating a standard cavity wall, but the savings on your heating bills will be bigger too. You might be able to reduce these costs by carrying out the work at the same time as other home improvements or by not tackling all the house at once.


There could be funding available to cover part of the cost of this measure, please contact us for further information.


We can through our partners ‘Work Work’ help our customers to purchase new home improvements like External Wall Insulation, and have flexible finance options available through Home Improvement Finance.


Variations in both building and insulation type make it difficult to provide an estimated cost for professionally installed EWI. As a guide, it will be in the region of £90 – £100 per square metre for a Terraced & Semi-Detached property, giving a total cost of £6,000 for a 60 Square Metre average sized Terraced House, to £8,100 for an average semi-detached house of 90 square metres. For larger properties where economies of scale are possible, the cost per square metre is likely to be less.

The final cost will be influenced by a number of factors including:

  • Insulation thickness and type
  • Size of the wall area
  • Number of windows and doors
  • Condition of the exterior surface
  • Ease of installation access and any scaffolding requirements.

Payment terms should be agreed before a contract is signed with Ete Energy Ltd which may include a deposit for a substantial part of the works.

See some of our projects below



Building Work



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