Are insulated plasterboards any good – Is it worth using them?

There are several ways to insulate a property. The most common way is via a combination of cavity wall insulation and internal insulation. The internal insulation is usually present in areas such as your loft, and internal stud walls.

In the mid 1990’s, insulated plasterboard was introduced to the market as an alternative, and it is certainly a convenient product, but are insulated plasterboards any good? And are they as effective as traditional insulation?

Insulated plasterboards offer a really good alternative to traditional cavity wall insulation. They are particularly useful if you have no way to add cavity wall insulation. For example, if a property has solid walls (no cavity).

It is also cheaper than adding external insulation, which will require a specialist team, scaffolding and rendering.

are insulated plasterboards any good

Let’s look at the benefits of insulation

A well-insulated house can offer many benefits. The most obvious, is a reduction in heat loss, but this is not the only benefit. This reduction in heat loss has several knock-on effects. For example:

  • Lower energy bills – because your property is better at holding on to heat, you won’t need your central heating on as much.
  • Lower your carbon footprint
  • More balanced temperatures and a more comfortable living space
  • Reducing internal condensation due to less cold surfaces. However, you will want to improve circulation and extraction to reduce levels of relative humidity.

Insulated plasterboard will significantly improve the U value of your walls. The U value is a rating that measures a surfaces heat loss per m2 in watts. The lower this number is, the better the surface is at retaining heat.

As an example, a standard cavity wall with no insulation, will have an average U value of around 1.5W/m2. By adding insulated plasterboard to internal walls, you would expect to lower the U value to between 0.2 and 0.3W/m2.

Solid walls are even less efficient and lose heat even faster. Therefore, adding insulation of any kind, can drastically reduce heat lost through the surface.

The average property loses more than 35% of its heat through the walls. This means that insulating your main external walls can lower your bills by as much as 20%.

So why choose insulated plasterboards

Obviously, you do have several options when it comes to insulation. The main ones for your external walls are:

  • Cavity wall injection – This is only an option if you have a cavity
  • External insulation
  • Internal insulation

If you have an existing cavity, you may benefit from cavity wall insulation being injected. This consists of an insulation being injected into the existing cavity. It is generally quite affordable. However, it is not without its issues, and many people have reported damp after it is installed. This could potentially happen due to cavity bridging. Or it could be the result of condensation and higher humidity in the property. Also, if you don’t have a cavity, this not an option.

After this, you’re left with external and internal. For external this involves adding insulation to the outside of your property and rendering. This can give a nice finish and will provide good insulation. However, it is more expensive.

With internal insulation, your biggest issue, is you will lose a small amount of space. Insulated plasterboards come in thickness of between 35mm-100mm. You can also add an extra 25-30mm for adhesive or timber battens, which will be used to fix insulated plasterboards.

Cost of insulated plasterboard

One of the main benefits of insulated boards vs an external solution, is they are cost effective and relatively simple to install. If you factor in labour, the price to install will be roughly £50/m2 (on average). This will vary slightly based on the thickness of insulation boards you use. However, the bulk of cost here is labour.

The cost of materials alone will be in the region of £20/m2 (on average). Again, factors such as, the thickness of the board, and the brand can affect price. As well as how you fix insulated plasterboard. Finally, you will certainly pay more for a popular well-known brand such as Kingspan.

Some more affordable brands include:

  • Gyproc
  • Knauf
  • Celotex

There really is no best brand of insulated plasterboard. Kingspan is considered the industry standard. However, other brands provide very similar thermal performance.

I personally have an outside office, it is insulated with 50mm Celotex insulation, and has excellent balanced temperature in both winter and summer.


Insulated plasterboards are a good solution for adding insulation internally. This is especially true if you are unable to install cavity wall insulation, and they offer an excellent alternative. If you do use insulated boards, they will significantly reduce heat loss through the walls of your property.

In combination with good loft and roof insulation, they can lower energy use and bills by a decent amount. This will help you save money and lower your homes emissions.