Internal wall insulation or external wall insulation?



Insulating your home is a great investment. Not only will you feel benefits in terms of comfort and warmth, but you will also see reductions in the costs of heating your home. A lot of heat can be lost through the walls of your house, but it is important to consider the building with a holistic approach – taking into consideration where else you might be losing heat. We will always survey your property before installing insulation and you can be sure that we will advise the most appropriate options. But what are the advantages and disadvantages of external and internal wall insulation?

External wall insulation: 

External wall insulation is generally preferable to internal wall insulation, as you are covering the whole of the outside and the insulation will act like a tea cosy! This method reduces the possibility of thermal bridging – where heat can be lost through areas left uninsulated. Insulating externally is not too disruptive as we won’t usually need access inside the property, apart from access to power and water. Furthermore, with a huge range of render colours available with a lovely clean smooth finish, external wall insulation can dramatically improve the external appearance of your home. Have a look at these jobs completed in Bristol:


There aren’t really any disadvantages to externally insulating your home, as long as the appropriate insulation is used and the work is carried out to a high standard. However, in some cases external wall insulation simply isn’t an option, which is where insulating internally is a good option…

Internal wall insulation:

If your house has special external features, you may not wish to lose them by covering them with external wall insulation. Similarly, if your home is in a conservation area, you may not be granted planning permission for EWI. Internal wall insulation is a great solution in these cases. We only use breathable insulation internally, to allow moisture to pass out through the walls, thus avoiding any possibility of interstitial condensation. Other products can be used of course, if due attention is paid to deal with the issue of moisture. We believe that wood fibre insulation offers the most robust and eco-friendly solution. We use a lime plaster which gives a really nice finish so you may not even wish to re-decorate afterwards!


For a more in-depth look at the considerations of internal wall insulation, have a look at Nick’s blog here

The only minor disadvantages to internal wall insulation are a slight loss of living space – between about 60mm and 80mm, and the disruption to your home life as you will need to clear the room. However, we believe this is a small price to pay for the advantages of warmth and comfort.

As always, if you have any questions about an insulation project you need doing, please give us a call on 0117 909 8090 or email


Author: Phoebe Westwood