If your home has solid walls, you could save £115-360 a year by installing solid wall insulation.
About a third of UK homes have solid walls, according to the National Insulation Association (NIA) — and an estimated 45% of the heat from these homes could be escaping through walls.
We've worked with the Royal Institution of Chartered Surveyors*, which publishes average building work and repair costs, to bring you the average cost for external solid wall insulation.
We've split it so you can look at the average costs for a terraced, semi-detached and detached house. Costs will vary depending on where you live in the country.
|House type||Price from||Price to|
|Table notes: This includes 100mm expanded polystyrene insulation (EPS) board to external brick wall, prime and render.|
The amount of money you'll save annually with solid wall insulation will depend on the type and size of your home.
The chart below shows the average reductions to heating bills and CO2 emissions for homes of different sizes.
Remember that the price you'll pay for external wall insulation will be affected by the condition of your walls and whether other building work or repairs will be taking place at the same time, as well as the size of your property.
Solid wall insulation is more expensive than cavity wall insulation, but it should eventually lead to bigger savings on heating bills.
Solid wall insulation can be applied to either the inside or outside of solid walls. A professional installer should be able to advise you on which option is most suitable for your home.
Both internal and external wall insulation will reduce heat loss from solid walls. The type you choose will be based on factors including:
External solid wall insulation is usually installed when a building has severe heating problems or already requires some form of external repair work.
Installation involves fixing an insulating material to external walls, with a protective render and/or decorative cladding over the top, so it will affect your home's external appearance. The thickness of the insulation needs to be 50-100mm.
External insulation is generally more expensive than internal, although you'll avoid the significant redecorating that comes with internal insulation.
Once your external insulation is fitted, you can use decorative coatings and cladding to improve your home's kerb appeal. This can match a wide variety of homes, including Georgian, Victorian and Edwardian properties.
Internal solid wall insulation usually involves fitting ready-made rolls or boards of insulating material to the inside walls of your house. This can be disruptive – you'll need to move plug sockets, radiators and fitted furniture, and redecorate your walls.
Your walls will need to be carefully prepared before internal wall insulation can be fitted. Any damaged plaster needs to be either repaired or removed, and bare brickwork should be treated to eliminate areas where air can escape.
The extra thickness of insulated walls will reduce your floor space ever so slightly.
This option is usually cheaper than external wall insulation and can be installed on a room-by-room basis.
*To arrive at the average prices above, RICS uses cost data from its Building Cost Information Service (BCIS) database, where costs are collated from a variety of sources and analysed.
Materials costs are based on the best trade prices from a range of suppliers across the UK, which are then benchmarked to reveal the best national average. Labour rates are based on the current Building and Allied Trades Joint Industrial Council wage agreement. Data copyright RICS 2021, reproduced with permission. Data is current as of October 2021.
Find the answers to your solid wall insulation questions:
If your home was built in the past 20 years, it's likely that the cavity walls have already been insulated.
If your home is more than 100 years old, it's likely to have solid walls. That means you'll need solid wall insulation to stop heat from escaping.
There is little financial help available to help you pay for solid wall insulation. Contact your council's energy efficiency officer to find out if something might be available in your area. Certain households might qualify for the .
Planning permission is not normally required for wall insulation.
However, if your property is listed, is in a conservation area or if the insulation will change the appearance of your property, you should consult your local planning authority.
Make sure you choose an installer registered with one of the following organisations:
Also check that your installer has signed up to a code of conduct, such as the NIA's Code of Professional Practice.
You can also contact Simple Energy Advice with any questions by calling 0800 444202.
You can buy jackets to fit around your hot water cylinder and piping. These are available from DIY stores and you can fit them yourself, as long as your pipes are easily accessible.
The energy savings are smaller than with wall or loft insulation but, as jackets cost around £15, they pay for themselves in a year or less.
You can also reduce the amount of heat lost in your home by fitting draught excluders around doors, windows and letterboxes. Gaps between skirting boards and floorboards are also worth tackling.
also cuts heat loss and reduces noise and condensation problems. You can expect savings of up to £115 a year on bills if you replace single glazing with double glazing throughout your house. Remember to close your curtains at dusk to stop heat escaping.