Internal wall insulation



  • Ideal solid wall solution
  • Reduce heat loss
  • Save money on energy bills
  • Increase EPC rating
  • Grant funding available


What is Internal Wall Insulation?

Internal Wall Insulation (IWI) is used to insulate solid wall properties. It is installed internally to the heat-loss walls and is a great solution when external insulation is not feasible or too costly.


Why insulate?

Solid walls let twice as much heat escape than cavity walls, and IWI is one of the most cost effective measures for improving thermal efficiency in the home. Typically up to 45% of heat is lost through un-insulated solid walls (Source: National Insulation Association, 2014). Rooms with internal solid wall insulation, when heated, become warmer much quicker – and in the summer it keeps the heat out too. The Energy Saving Trust estimates solid wall insulation can cut fuel bills by up to £455 per year.


What system is right for me?

We provide a range of IWI systems in order to meet the specific needs of your property. All our systems have BBA certification and are designed to be installed directly on to an existing solid wall in one easy installation. Once completed all systems will leave a smooth plaster finish that requires minimal decoration. All our IWI installers have completed a rigorous manufacturer training programme so that the system is always installed correctly and consistently.

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Case study

Internal Wall Insulation can be installed using two different types of system:

Studwork & Mineral Wool

This method uses a thermal studwork frame with mineral wool insulation and waterproof membrane to create a fully flexible IWI system. Once fitted, walls are finished with plasterboard leaving a fresh and clean surface for redecoration – perfect for those looking to redecorate and renovate their home.

Insulated Plasterboard

This type of system use specially manufactured insulation-backed plasterboard with integrated vapour barrier. The thickness of the insulated plasterboard dictates the performance, and the insulated plasterboard can either be screw-fixed or wet-fixed to the existing walls. Just like studwork systems, insulated plasterboard leaves a fresh and clean surface for redecoration.

In either case all existing fixings, such as electrical sockets and radiators, are removed and refitted onto the new IWI system, and this is included as part of the installation. Both studwork and insulated plasterboard systems provide maximum heat-loss efficiency while minimising the encroachment of room space.


What funding is available?

ECO – Energy Company Obligation grant funding is available to most households, and may be available to cover up to 100% of installation costs.

Green Deal – make energy efficient home improvements using Green Deal finance, which you can repay through your energy bill savings.

HEEPS Cashback – Scottish Government scheme provides rebates of up to £5,800 on a variety of measures on qualifying properties.

HEEPS Loan – interest free loan of up to £10,000 for owner occupiers and registered private sector landlords.

To access funding, measures should be recommended in a pre-installation Green Deal Advice Report for the property and carried out by a certified Green Deal Installer.

We can help you access your funding at no additional cost.


Green Deal Installer

Green Home Systems Limited is accredited with NICEIC to install IWI systems through the Green Deal and ECO. This means that we are able to access grant funding and Green Deal finance.

As a member of SWIGA we provide a 25 year insurance-backed guarantee on all our IWI projects.

For more information please contact us.


Further information

For more information on internal wall insulation we recommend the following websites:

Energy Saving Trust – providing free and impartial advice on energy efficiency

National Insulation Association – industry body setting and maintaining standards

Which?independent consumer advice



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