How Much Does Cavity Wall Insulation Cost?

A Look at Cavity Wall Insulation Pricing Per Square Metre + Per House

Most of us know what cavity wall insulation does – it’s a filler injected into the space between the inner and outer walls, keeps our homes warmer, and helps reduce our heating bills.

This stuff has been in the news for decades and most of us have at least heard of it before.

But how much does cavity wall insulation really cost to install in a typical house?

What is the average cost per square metre?

Does the government offer discounts?

About These Prices

The prices shown below:

  • Are based on prices we sourced from 26 cavity wall installers in December 2021.
  • Are for EPS beads – one of the most popular types of cavity wall insulation.
  • Exclude government or energy supplier discounts.
  • Exclude scaffolding, as not every home requires it.
  • Include VAT if it was charged by the installer.

As the figures below are an average of the prices given to us, we believe they’re an excellent guide to the going rate for cavity wall insulation in the UK:

Cavity Wall Insulation Price Per Square Metre

The average cost per square metre of wall, excluding windows and doors, came in at:

£10.50 per square metre.

Cavity Wall Insulation Prices Per House

While we only sourced prices for cavity wall insulation to a 3-bed semi-detached home, we can use the “per square metre” figure to easily calculate the cost for other homes:

1 or 2-bed small mid-terrace or corner house: £400

1-bed end of terrace: £600

2-bed end of terrace/semi: £700

3-bed semi: £800

2-bed detached: £900

3-bed detached: £1100

4-bed detached: £1200

4-bed large detached: £1500

Government-Backed Discounts and Schemes

Over the years, there have been various green schemes, and the most recent – The Green Homes Grant – ended on the 31st March 2021.

In the UK, energy companies offer heavily discounted or free insulation to homeowners and some private tenants, provided that at least one person in the home receives certain benefits.

This is part of the ECO scheme, backed by government legislation.

Contact your energy supplier for more details if you believe you may qualify.

Which Type of Insulation is Best?

We chose EPS beads (polystyrene balls) as they are least likely to cause damp problems.

Should you be worried about potential damp?

Well, yes, there is a genuine risk of the insulation getting wet and damp penetrating into the home.

This is more likely if:

  • Your wall is in an exposed location that gets lashed with rain.
  • The brickwork is in poor condition, cracked or has missing or degraded pointing.

While EPS beads are least likely to cause damp problems, no type of insulation should ever be put into cavities where the walls are in poor condition and/or in windswept locations.

Beware of Mis-Selling

There are plenty of homes in the UK that should never have cavity wall insulation fitted.

In fact, one MP described the mis-selling of this insulation as the next PPI scandal.

In short, if you live in a windswept location, i.e any part of west Scotland, west Wales or the south-west, any coastal area or any elevated area, cavity wall insulation probably isn’t for you.

But don’t expect a cavity wall insulation company to tell you that.

Get a Custom Price for Cavity Wall Insulation

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This guide to cavity wall insulation costs was created by the team here at DIY Gardening

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