Insulation Type

Internal Wall Insulation

Insulate solid walls from the inside to reduce heat loss and lower energy bills — without changing the exterior of your home.

What Is Internal Wall Insulation?

Internal wall insulation (IWI) involves fitting insulation boards or a stud wall with insulation to the inside of your home's exterior walls. It is an effective solution for solid-wall properties where external insulation is not suitable — for example, listed buildings or properties in conservation areas.

While it slightly reduces the room dimensions, IWI can significantly cut heat loss and improve comfort. It also eliminates cold interior wall surfaces, reducing condensation and the risk of mould.

Internal Wall Insulation

Up to 40%

Heat Loss Prevented

£200–£350

Annual Savings

1–2 weeks

Install Time

£0

Cost to You

Check If You Qualify for Free Internal Wall Insulation

Enter your postcode to start your free eligibility check.

Benefits of Internal Wall Insulation

Here's what you can expect when internal wall insulation is installed in your home through a government grant scheme.

Reduces heat loss through solid walls by up to 40%
Saves £200–£350 per year on energy bills
Preserves the external appearance of your property
Eliminates cold wall surfaces and condensation
Improves your EPC rating significantly
Ideal for listed buildings and conservation areas
Can be installed room by room if preferred
Fully funded through government grant schemes

How It Works

1

Check eligibility

Enter your postcode to see if you qualify for free internal wall insulation through ECO4 or HUG2.

2

Home survey

A retrofit assessor evaluates your walls, room layouts, and any damp issues to design the best approach.

3

Installation

Insulation boards are fixed to exterior-facing walls, then finished with plasterboard and a skim coat ready for decoration.

4

Start saving

Your rooms feel warmer immediately, with noticeably fewer cold spots and draughts along exterior walls.

Register Your Interest

Leave your details and we'll contact you about free internal wall insulation.

Frequently Asked Questions

Other Insulation Types

External Wall Insulation

Wrap your home in a thermal layer to cut heat loss by up to 45% — ideal for solid-wall properties.

Learn more

Cavity Wall Insulation

Fill the gap between inner and outer walls to reduce heat loss by up to 35% — fully funded through government grants.

Learn more

Underfloor Insulation

Stop heat escaping through your floors — particularly effective in older homes with suspended timber floors.

Learn more

Check Your Internal Wall Insulation Eligibility

Enter your postcode to find out if you qualify for free insulation through government grants.