As well as looking at ways in which we can minimise the energy we use, it is just as important to try to minimise the amount of energy that we lose, after all, climate change is a challenge we all face and losing heat through walls is not helpful also a waste of money and the earth’s resources.

Why is it green?

It prevents heat loss, so you are not wasting the energy for which you are paying, or generating through renewable technology (but more on solar panels in a later post!).

What’s involved?

The first question to be answered is what types of walls are you trying to insulate?  The type of insulation will depend on the construction of the building, you may have cavity walls, or they may be solid.  Older properties tend to be solid walls and these can either be insulated from the inside or the outside, and these come with their own drawbacks and challenges.  Externally a layer of insulation can be added to the external wall, then using render to provide a finish.  This is quite expensive and may require planning permission, especially if the building is listed or in a conservation area.  Internally, it can be achieved by fixing insulating boards to the walls, this is quicker and cheaper, but will reduce your floor area, involve considerable disruption to home life and redecoration.  Again, on a listed building this would require approval.  A cavity wall comprises of two walls, usually solid, with a narrow gap between them.  To insulate these walls a special material is injected through the walls by using small holes and then the holes are filled.

Can you DIY?

Injection insulation of cavity walls and external insulation on solid walls is definitely a job for a competent professional with all the necessary indemnity and expertise in the area.  You may be able to do some of the internal insulation yourself, but a professional will probably do it much quicker and, unless you are very skilled at DIY, you will get a better finish.

How much does it cost?

On a three or four bed detached house with solid walls you could expect to pay about £8,500 for internal insulation and about £15,000 for external.  Cavity wall insulation for a similar sized property would be about £750.

Does it save money?

It does, but beware of pay back periods if money is the only consideration.  Solid wall insulation will save about £250 per year (inside or out) and cavity wall insulation about £150.

Can it be done in a church?

It can, but a larger building would mean an increase in costs, and it is most cost effective in a building that has to maintain a constant heat for long periods, as opposed to one which is used for only short periods.

Other Thoughts?

This can be an intrusive process, which may not be welcome, there can be a very long payback period, and a building, however well insulated, will lose heat over time. If you only use a building occasionally, then you may see no savings at all, it would just be a cost. 

The insulations of a cavity will leave a number of holes externally to be filled, and if this is not done sensitively and in keeping will make the building look as if it has spots!  As usual, any work on a listed building, or one in a conservation area, will need approval for any of this work.