How to save energy with solid wall insulation

Solid wall insulation is a great way to make sure the heat you use stays inside your house, and stop your energy bills going through the roof.

If you’re not sure what insulation you need at your house, this handy guide will explain everything you need to know. And although there will be an initial outlay involved, the money you save on heating should cover the installation costs in no time at all, meaning once your insulation is fitted you’ll be feeling the benefits almost right away.

How to check if your home has solid walls

Before you go getting home insulation quotes, you’ll need to know if your walls need solid wall or cavity wall insulation, and there are a few of ways you can check whether your walls are solid.

The easiest way is to find out when your house was built - the older your home (think beginning of the 20th century or earlier) the more likely it is to be solid walled. But if your property is newer, it’s more likely to have cavity walls, which are made up of two layers, with a gap in between.

Do you need internal or external wall insulation?

Once you’ve worked out whether or not your walls are solid, you can go ahead and get installation quotes. If they’re solid though, you need to decide whether you’re best getting internal or external wall insulation – both do the same job and are equally as efficient, so whichever you choose comes down to personal preference and affordability.

External wall insulation is much more expensive than internal. For a start, it can’t be done on a room-by-room basis, so you’ll need pay for the whole house to be insulated in one go. Secondly, it involves much more installation material. But the benefit is that it can be less disruptive to the inside of your home.

By contrast, internal wall insulation can become quite a mess. Firstly, you need to ensure your internal walls are ready to have thick layers of insulation installed, which means they can’t have any signs of damage. Insulating damaged walls means there’s a chance air can escape, meaning you could still lose heat and make the insulation pretty pointless. On the plus side, this approach, is cheaper and can be done on a room-by-room basis, which gives you flexibility to manage the installation how you want.

External wall insulation

This involves adding a decorative weather-proof insulating treatment to the outside of your wall. The thickness of the insulation needs to be between 50 and 100mm and is usually installed where there are severe heating-escape issues, or the exterior of the building requires some form of other repair work; providing the opportunity of adding insulation.

This insulation method could save you £290 to £350 a year on you energy bills.

The cost for external wall insulation, including the insulation and labour costs while wall repairs are being undertaken, starts at £1,800 for a semi-detached house.

Internal wall insulation

Solid walls can also be insulated by applying internal wall insulation. You can use ready-made insulation/plaster board laminates or wooden battens in-filled with insulation or flexible linings.

Insulation/plaster board laminates usually consist of plasterboard backed with insulating material, typically to a total thickness of up to 90mm. Installing them involves the boards being fitted directly to the inside of the wall, and the thicker the board, the better the insulation.

You can also attach wooden battens in-filled with insulation to a wall for added insulation. This involves attaching battens to the wall, filling the spaces between the battens with insulation and then covering them with a plasterboard finish.

Costs for internal wall insulation start from £40 per square metre, and you could save between £270 and £340 a year on your energy bill.

Can you get solid wall insulation if you are a tenant?

This comes down to the landlord’s discretion, and whether they want - or will allow - you to get wall insulation. There are grants and funding for both tenants and landlords, but this is something you will need to discuss with the owner of your home.

How much does solid wall insulation cost?

Solid wall insulation costs can vary greatly - according to the Energy Saving Trust, internal insulation can cost anywhere between £4,000 and £14,000, while external wall insulation can cost anything from £8,000 to £22,000.

The reason prices vary so much is two-fold: the size of your home and the type of insulation you want. If you have a large home and are looking to get external insulation, then that will set you back. But again - it is worth it. In regards to cost, as mentioned earlier, internal wall solutions can be really handy, because you can prioritise the rooms you wish to insulate first, spreading the cost out across a number of months.

Is any help available towards the cost of insulation?

Some local authorities will offer help towards insulation costs, and it’s worth checking the Energy Saving Trust website for information on which grants and funding are available in your area.

And contact your local authority and see what help they can offer, though you may find they only offer assistance for loft or cavity wall insulation, which are usually much smaller jobs than installing solid wall cavity insulation.

Save even more on your energy bills

As well as solid wall insulation, there are a number of other ways you can modify your house, or energy efficiency tips you can adopt to lower the amount of gas and electricity used to power your home.

You can also use an online energy comparison tool to find out if you could be on a more competitive tariff for your gas and electricity. Simply enter your postcode into the form on the right to get started. It only takes a few minutes and we'll handle the energy switch for you.