Planning your home insulation

In this post, we explain how to properly insulate your home, from top to bottom, including the roof, loft, walls, and floor.

We look at the cost of these home improvements and also the green home grants available to help make them more affordable for all.

The benefits of home insulation

Generally speaking, making eco-improvements such as installing home insulation, brings several benefits:

• It helps to reduce household energy bills, create a warmer home, and cut carbon emissions
• It helps to work toward the UK government’s target for all homes to have an Energy Performance Certificate (EPC) rating of C by 2035
• It could increase the value of your home: With energy-efficient homes in high demand, they tend to have a higher market value

Is it worth investing in home insulation?

According to an Admiral Money survey, solar panels are the most lucrative eco improvement a homeowner can make, however, home insulation comes a close second.

A well-insulated home is warmer and has lower energy bills: Loft insulation alone could save you up to £315 per year according to the Energy Saving Trust.

What’s more, a well-insulated home is attractive for home buyers, keen to reap the benefits of an insulated home without the cost or upheaval of fitting insulation retrospectively.

For this reason, insulation could boost your home’s value by up to 22%.

What’s the best type of insulation for my home?

Loft insulation is perhaps the most well-known type of insulation, but there are various options available, including cavity wall insulation, solid wall insulation, external wall insulation, floor insulation, and roof insulation.

If your home was built after the 1920s, it’s likely to have cavity walls (homes built before this are more likely to have solid walls).

Cavity wall insulation must be done by a professional, who will drill holes in the outside walls, inject insulating material into the cavity, and then seal the holes.

For homes with solid walls, you have the option to insulate from the inside or the outside.

Internal walls can be insulated by fitting rigid insulation boards to existing walls, or building a stud wall and filling it with insulation material. For insulating boards, a thickness of around 60-100mm is suggested.

External walls can be insulated by adding a layer of insulation material and then finishing it with plaster or cladding.

Overall, insulation comes in various types and it’s not necessarily a ‘one size fits all’ approach.

Blanket insulation (made from fibreglass or mineral wool) is one type of insulation, popular as a cost-effective option for loft spaces and internal stud walls.

Alternatively, loose-fill insulation can be used to top up existing loft insulation. The government recommends loft insulation to be 270mm deep.

An insulation expert will be able to advise on the most suitable type of insulation for your particular type of property, ensuring you receive maximum benefit from the work.

How much does home insulation cost?

Unless you’re researching the cost of insulating a new build, you’ll be looking at fitting insulation retrospectively. Costs can be slightly higher as your tradesperson will need to work around existing structures, pipework, and cables.

The costs outlined below are ballpark figures to act as a guide to retrofit home insulation for an average semi-detached house.

Loft insulation

Laying insulating material between the joists in the loft is one of the easiest types of insulation to do retrospectively.

Providing you have easy access to the loft, budget for between £600 – £1,000.

Read our guide to loft insulation costs for more detailed information.

Roof insulation

Roof insulation involves insulating the space between the rafters in your loft space.

Expect to pay anywhere between £3,000 – £4,000 for roof insulation.

Cavity wall insulation

Cavity wall insulation is one of the cheapest options available, filling the gap between the wall cavities with insulating material such as foam or mineral wool.

This typically costs around £800 – £1,200.

Solid wall insulation

Alternatively, if you have solid walls, they’re unlikely to be insulated. You can have solid wall insulation applied internally or externally retrospectively, although it is a little more costly.

You’re looking at around £8,000 – £10,000 to insulate a solid wall from the inside or £10,000 – £12,500 for external wall insulation.

NB. Adding insulation retrospectively might make it necessary for adjustments to be made to your home’s ventilation. Check with your tradesperson before work commences and ensure these additional costs are included in your quote for the work.

Floor insulation

There are three main types of floor insulation – an experienced tradesperson will be able to help advise the best option for your home.

• Suspended floor insulation costs around £1,500 – £3,000 per ground floor
• Suspended timber floor insulation costs between £1,500 – £3,000 per ground floor
• Solid floor insulation costs around £2,000 – £4,000

As you might imagine, to fit floor insulation, skirting boards and floorboards will need to be removed and replaced. Do check this is included in the quote you receive for the work.

Read our guide to the cost of floor insulation for more information.

Double or triple-glazing

Don’t forget your windows and doors. Double or triple glazing is a great way to insulate your home, making it warmer and reducing outside noise. You’ll also recoup some of your investment in this eco-upgrade if you come to sell your property – double-glazing can increase your property value by up to 10%.

The average cost of double glazing for eight windows and two uPVC doors is £6,000 – £15,000. 

Read our guide to draught-proofing your home for a selection of tips to create a warmer home.

Insulating pipes

Another area of your home that you may not have considered insulating is your pipes.

You’ll have an outdoor pipe to connect your home to the main water supply and a condensate waste pipe if you have a boiler. It’s also likely you have pipes in your loft and garage and exposed indoor pipes connected to your heating system.

To reduce the risk of the external pipes cracking/bursting in low temperatures and heat loss from internal pipes, it’s recommended to insulate them.

• The average cost of pipe insulating materials is £1.60 per metre for 15mm (diameter) and 13mm (thickness), with labour cost averaging £200
• The average cost to insulate the condensate pipe from the boiler is around £200
• The average cost to purchase an insulating outside tap cover from a DIY store is £10 

Can I get my home insulated for free?

While many homeowners want to make eco improvements to their homes, one of the main barriers is the upfront costs involved.

In this section, we’ll outline the government green schemes available to help make these home improvements more affordable.

Loft insulation grant

ECO4 Scheme

If you’re looking for a grant for loft insulation, (or even double-glazing, or boiler upgrades), take a look at the Energy Companies Obligation scheme (ECO).

ECO is a government energy efficiency scheme designed to tackle fuel poverty and help reduce carbon emissions.

ECO has four iterations. The ECO4 scheme applies to measures installed from 1 April 2022 and will cover a four-year period until 31 March 2026.

To benefit from the scheme, you must either be a homeowner or have permission from your landlord. Check your eligibility for the ECO4 scheme here.

The Great British Insulation Scheme

Alternatively, for cheaper or free loft insulation, take a look at the Great British Insulation Scheme.

It may be a way to get support to install a variety of home insulation, including cavity wall insulation, loft insulation, floor insulation, and more.

Support could be available if your home:

• Has an energy performance certificate (EPC) of D to G – check your EPC
• Is in Council Tax bands A-D in England or A-E in Scotland or Wales – check your Council Tax band

Government window scheme

While there’s no specific scheme for help to buy windows, there are numerous funding schemes to promote energy efficiency and eco-improvements (including double-glazing). As a first port of call, research your eligibility for ECO4 (scroll up if you missed it).

The energy grants listed are part of the government’s £12 billion investment in Help to Heat schemes to make sure homes are warmer and cheaper to heat.

There’s also The Green Deal. This is a loan-based scheme that helps you to make energy-saving improvements to your home and find the best way to pay for them.

NB. To benefit from the government grants for these eco-improvements, it’s sometimes necessary to hire a tradesperson registered with TrustMark, which many of our members are.

Finding insulation experts you can trust

The final piece of the puzzle is finding reliable experts you can trust to install your home insulation to the highest standard.

Sometimes this can feel like a minefield. To be confident of hiring right, the first time use a trusted website, such as Checkatrade, to see who comes highly rated in your area.

You can also use Checkatrade to check a tradesperson’s industry certifications. For example, an insulation specialist might be a member of the National Insulation Association (NIA). For double-glazing companies, check for membership to trade associations such as FENSA.

On Checkatrade, you'll only find trades who meet our high standards and pass up to 12 checks.

We have more than 25 years of experience approving tradespeople to join our leading directory. Therefore you can be sure you’re getting top-quality work from a range of industry professionals, happy to share their knowledge to advise the best solutions for your home.

To find trusted experts in your local area, simply add your postcode to the search box below