Insulation costs for different types of home
Insulation is essential for preventing heat from escaping a property, helping to reduce energy use and bills.
Depending on your home, it's possible to add insulation to your roof, walls, floors and loft, along with draughtproofing cracks and gaps around windows, doors and chimneys.
The type of property you live in, from terraced to detached and historic buildings, will impact the choices you can make about insulation, and how much it will cost to fit.
Our cost data is provided by the Royal Institution of Chartered Surveyors (RICS), and represents national average for the material and labour costs involved with each type of insulation installation.
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Insulating terraced houses
Also known as townhouses or row houses, terraced houses are properties that share at least one wall with a neighbour, and often are a long line of homes joined together.
This offers some energy efficiency benefits as the side walls are shared rather than external, so lose less heat to the outside.
As heat rises, the roof is the main area that it can escape from a terraced house, so insulating any loft, attic or roof space is particularly important. However, this will be beneficial for all types of homes.
External wall insulation could be added to front and rear walls, as they are exposed to the outside and need additional barriers to prevent heat loss.
Join Which? today to reveal how much it costs to insulate a terraced house:
| Type of insulation | Cost |
| Loft insulation: Glass mineral wool insulation quilt laid over and between the joist, 300mm thick | |
| Solid wall insulation - external: 100mm Expanded Polystyrene Insulation EPS board to external brick wall, prime and render | |
| Cavity wall insulation: Injected polystyrene beads to wall, cavity width 100mm. Making good all holes on completion | |
| Floor insulation: Floor insulation to exiting suspended ground floor, 150mm thick rockwool insulation slab laid between joists from above (lifting floor boards), re-fitted the floor boards using existing boarding, making good on completion |
Loft and floor insulation area: 24m2. Solid wall (external) and cavity wall insulation area: 37.5m2. Data copyright RICS 2023, reproduced with permission. Data is current as of December 2023.
As insulating the roof is vital in a terraced house, find out everything you need to know in our guide to roof insulation.
Insulating detached houses
A detached house is a standalone structure that does not share any walls with neighbouring properties. This means heat can escape on all sides of the house, so more insulation is required.
Wall insulation is a much more important consideration for detached houses, as the area for heat to disappear through is so much larger.
Floor insulation can also be very beneficial, particularly in older homes, as it prevents heat from being lost downwards.
Join Which? today to reveal how much it costs to insulate a detached house:
| Type of insulation | Cost |
| Loft insulation: Glass mineral wool insulation quilt laid over and between the joist, 300mm thick | |
| Solid wall insulation - external: 100mm Expanded Polystyrene Insulation EPS board to external brick wall, prime and render | |
| Cavity wall insulation: Injected polystyrene beads to wall, cavity width 100mm. Making good all holes on completion | |
| Floor insulation: Floor insulation to exiting suspended ground floor, 150mm thick rockwool insulation slab laid between joists from above (lifting floor boards), re-fitted the floor boards using existing boarding, making good on completion |
Loft and floor insulation area: 125m2. Solid wall (external) and cavity wall insulation area: 211.2m2. Data copyright RICS 2023, reproduced with permission. Data is current as of December 2023.
Learn how to prevent heat escaping from all sides of your detached home in our guides to solid wall insulation and cavity wall insulation costs and savings.
Insulating semi-detached houses
A semi-detached house shares one wall with a next door property, making it slightly easier and cheaper to install insulation.
The requirements are still broadly the same as detached houses, with roof, floors, walls and draughtproofing all helpful for improving energy efficiency.
Join Which? today to reveal how much it costs to insulate a semi-detached house:
| Type of insulation | Cost |
| Loft insulation: Glass mineral wool insulation quilt laid over and between the joist, 300mm thick | |
| Solid wall insulation - external: 100mm Expanded Polystyrene Insulation EPS board to external brick wall, prime and render | |
| Cavity wall insulation: Injected polystyrene beads to wall, cavity width 100mm. Making good all holes on completion | |
| Floor insulation: Floor insulation to exiting suspended ground floor, 150mm thick rockwool insulation slab laid between joists from above (lifting floor boards), re-fitted the floor boards using existing boarding, making good on completion |
Loft and floor insulation area: 42m2. Solid wall (external) and cavity wall insulation area: 95.37m2. Data copyright RICS 2023, reproduced with permission. Data is current as of December 2023.
Find out how to draughtproof your home with our expert tips. Draughtproofing is another way to increase the insulation and heat-capturing effectiveness of your home.
Insulating historic properties
Ancient or simply older properties built prior to modern techniques and building regulations can be more complicated to add insulation to.
Special techniques or materials may be needed, and cost could increase due to this.
If a property is Grade I, II, or II* listed, it is protected by law to stop its historic features being changed. This means planning permission will likely be required to make any changes, such as installing insulation, and there will often be limitations about what can be altered, and the materials that can be used.
Historic England has detailed guidance on retrofit and energy efficiency in historic buildings.
For more ideas on improving energy efficiency, check out our guide to how to insulate your home, which includes explanations of Energy Performance Certificates (EPC).