Does insulation paint work?

What is thermal insulation paint?

Thermal insulation paint first entered the energy saving market back in the late 1990s. Since then, there has been an increase in companies looking to exploit the seemly attractive potential in insulating paint. Insulating paint is said to consist of honeycomb or ceramic hollow balls supposedly invented by NASA, which don’t just slow down the heat transfer through the walls but actually stops it all together! Therefore the heat has no choice but to go back into the room. This means that your rooms don’t take as long to heat up and you don’t have to have your boiler on for as long.

Conventional insulation, installed internally, tends to involve 25mm of PIR board or 50mm of wool; although as building regulations have tightened up you can sometimes find an even thicker layer of internal insulation. The result of this thick layer of internal insulation is a reduced footprint of the rooms since it brings in the walls and reduces space available in the home. Insulating paint is obviously nowhere near that thickness, yet many companies claim that their product still offers 25% savings on customers heating bills. As paint is only applied to around a millimetre thick, these are truly incredible results – but are they true?

Are there independent studies on insulating paint?

Independent studies tend to be lacking on product pages for thermal insulation paint. Instead you might find Mrs. Smith saying “What a wonderful product, I’m so warm now”. “Scientific studies show” is also a go-to phrase used by the insulating paint market. When Alex Wilson, a well-known sustainability expert, was asked about the claims that insulating paint generates savings in domestic homes, he stated “they are making claims that defy the laws of physics”. It is claimed that thermal insulation paint works in a different way to traditional insulation techniques, in that it prevents heat from leaving the room. This would actually cause a build up of condensation as opposed to solving the problem.

How does conventional thermal insulation work?

Conventional insulation works by slowing the movement of heat from one side of the insulation to the other. As you might expect, it is often true that the thicker the insulating material, the slower the movement of heat across it. It is all worked out in thermal conductivity measurements and U-Values. This means that your boiler doesn’t have to work as hard because it doesn’t have to replace as much lost heat. Insulation is very easy to measure, as all materials have a thermal conductivity value – which basically shows you how quickly heat is transferred through the object. A whole wall with solid brick and insulation will then have a U-Value – this is worked out by taking the thermal conductivity and the thickness. Whereas savings in cost and heat are easy to measure in conventional insulation techniques, it is impossible with thermal insulation paint. Using just the paint, you would have to have a layer of around 200mm to get the wall down to somewhere close to building regulations. That’s 4/8 times as much as the internal solid wall insulation.

What are the better alternatives to insulation paint?

Better alternatives do exist, although they differ in size, shape and effectiveness. Firstly, if you don’t want to lose any space in your home but your property is cold, then you should look to add insulation externally. This is called external solid wall insulation. As it is installed externally you can get thicker insulation, meaning increased savings and quicker payback – not to mention a warmer house. However, this is fairly expensive and can change the look of your property.

If you chose internal solid wall insulation, you would only install a thickness of around a half of what you would do externally. Although this insulation would still save you money and increase comfort, the payback will be slightly more as the costs are comparable.

For a thinner solution, Wallrock Thermal Liner KV600 offers a 4mm wallpaper which is designed to slow down heat loss. This obviously won’t have the same effect as internal or external solid wall insulation, but it has been proven to reduce your wall’s U-Value from 2.1 to 1.79W/mtr2K – and comes at a reduced cost.

In conclusion, the claims made by the insulating paint companies seem a little outlandish to us. There are proven methods of reducing heat loss and these are all backed by science. If you are looking to insulate your home, you might be better off investing your money in a proven technology!

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