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What Are The Different Types Of Insulation

With energy prices rising at an extraordinary rate in 2022, you may be one of the millions of homeowners looking at ways to reduce their energy costs by installing insulation or updating the existing insulation in your home. 

If you’re wondering what are the different types of insulation available to you, see our list of different types of insulation that can help to reduce heat loss in your home below: 

The different types of insulation available are:

  • Cavity wall insulation
  • Loft insulation
  • Room in roof insulation
  • Internal wall insulation
  • External wall insulation. 

Get Help With Insulation

Free Insulation Scheme offers a completely free service to help you to access grants available under the government’s ECO funding scheme. The scheme means that home insulation upgrades can be completed for free or with a small contribution. 

The Free insulation scheme team will also arrange the fitting of the insulation by certified and fully accredited insulation experts from start to finish. Simply get in touch with our friendly team to check if you’re eligible and be on your way to a more energy-efficient home in no time! 


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Read on to understand more about the different insulation available and whether they’re covered by the government funding grants available to put towards the cost of home insulation.

Cavity Wall Insulation 

If your home was built after the 1920s, it’s likely to have cavity walls. A cavity wall refers to the small gap between two separate thin walls that make up the exterior of your home. These walls are usually made from brick and are held together with metal wall tiles. 

It’s the space between the two bricks that can be filled with insulating material to reduce heat loss from your home. The insulation used to fill cavity walls is usually mineral wood or polystyrene eats or polyurethane foam and is installed by drilling regular 1-inch holes into the walls before pumping in the insulation. 

If you have a brick house built between 1924 and 1982 it’s likely to be suitable for cavity wall insulation but newer houses built in the last twenty years are likely to already have cavity wall insulation installed. If you’re unsure if your home already has cavity wall insulation there are several ways you can check;

  • Firstly, look at any exposed brickwork. If every other brick laid is showing the short side of the brick, then you won’t have a cavity to fill within the brickwork but if all the bricks are facing the same way, then you are likely to have a cavity wall. 
  • Secondly, you can ask an approved cavity wall installer to drill a small hole through the brickwork to check for cavity insulation. This is called a borescope inspection. 
  • Thirdly, you can contact the building control team at your local authority offices as they will have a record of previously insulated walls. 

Cavity Wall Insulation Cost Vs Saving

Around a third of all heat lost from the home is through the walls, making cavity wall insulation one of the most cost-effective ways to insulate your home. The cost of installing cavity wall insulation will vary depending on the size of your home. Smaller properties will need less insulation material and take less time to complete the work, therefore cost less to install cavity wall insulation than a larger home. 

Whatever size your home is, cavity wall insulation will usually pay for itself over around 5 years or less. For example, a semi-detached home would typically cost around £475 to insulate which would lead to around £165 saving per year in heating costs.

Cavity Wall Insulation Grants Available

All private homeowners that are receiving a qualifying benefit can claim a 100% free cavity wall insulation grant, as long as the house is occupied and does not have renovation work being completed.


Loft Insulation

Loft insulation is when a barrier of material is installed into your roof space that traps heat and can therefore reduce heat loss in your home. Loft insulation can be made from a variety of materials but glass fibre is the most popular. The loft insulation material chosen can be laid between the joists on the floor of the loft space or in between the rafters that support the roof itself. 

It’s recommended that to cut energy bills up to 20%, you should effectively insulate your loft. The recommended depth for loft insulation is 270 millimetres for glass wool, 250 millimetres for rock wool or 220 millimetres for cellulose.

Other materials that can be used for loft insulation include PIR board, phenolic foam, sheep’s wool, hemp, recycling polyester, foil-based, stone wool or wood fibre.

Loft Insulation Cost Vs Saving

Loft insulation is relatively cheap to install with a typical medium-size home costing on average between £300 – £400 to insulate. It’s worth noting that if you want to use the loft space for storage after insulating, you will need to add a layer of wooden boards to provide a level flooring to walk on or store things on and this may increase your initial payout. Loft insulation could reduce your energy bills by up to £315 per year, depending on your home.

Loft Insulation Grants Available 

In order to qualify for a Government loft insulation grant, there needs to be 100mm (4 inches) or less of insulation already installed in your loft. Usually, this will be level with or below the joists. If it is over this level, you could have a survey and a quote to top up to 270mm.

Room In Roof Insulation

Room in roof insulation involves adding insulation boarding between the rafters underneath the 

existing plasterboard walls in your roof space. The insulation boards are usually made from polystyrene or polyurethane which are effective materials for trapping heat and therefore reducing heat loss from the roof of your home. 

To be able to have this type of insulation put in place, the home needs to have been constructed with roof rooms or have a loft conversion. There should be little to no insulation in the walls and ceiling and you must have a fixed staircase (not a pull-down loft ladder or something similar).

If you’re unsure if you have a qualifying room in the roof at your home, these rooms are usually a feature of a bungalow that has had a loft conversion that is accessed from a fixed staircase, but it can also be an original building feature. Typical characteristics of a room in roof will be sloping ceilings and dormer windows on the upper floor.  

Room In Roof Cost Vs Saving

With nearly a quarter of all heat lost from the home being lost from the roof, insulating a room in the roof properly can save you significant sums of cash on your energy bills.

Room In Roof Grants Available 

The free insulation team can help you to access government grants available under the ECO funding scheme to install room in roof insulation.  

Internal Wall Insulation

Internal insulation refers to insulation that is applied to the inner face of external walls in a building. The building must have walls that are of solid construction type for you to be able to have internal wall insulation put in, and the insulation is usually attached to the wall from the ground floor up to eaves levels. 

The insulation prevents heat from being lost through the exterior walls of your home by creating a heat loss barrier between the internal and external walls. Internal insulation boards can usually be made of wood fibre but calcium silicate, clay, cork, hemp, polystyrene and plasterboards can all be used. 

Internal wall insulation can be disruptive and require the removal and refixing of fixtures and fittings including light switches, radiators and kitchen units so that an airtight installation can be achieved. The usual installation methods include fixing insulation directly to the wall, battening the wall, constructing a new stud wall, or applying insulating plaster directly to the wall, which works well for stone walls. 

Internal Wall Insulation Cost Vs Saving

Typical costs for internal wall insulation range from £40-£50 per square metre and internal insulation is often less expensive than external wall insulation. 

Internal Wall Insulation Grants Available 

There are grants available for internal wall insulation for solid walls for qualifying households under the government’s ECO scheme. If someone in your household is claiming a benefit, you might be entitled to free internal wall insulation for your home.


External Wall Insulation

External wall insulation creates a protective heat loss barrier to reduce the amount of heat lost from the walls of your home which is where up to a third of all heat is lost from the home. External wall insulation is when a layer of insulation is fixed to an existing exterior wall of your home and is best suited to homes with solid walls and when cavity wall insulation is not an option. Most homes built before 1920 have solid walls and the insulation applied is usually finished with render or cladding to protect it from the weather.  

External Wall Insulation Cost Vs Saving

Prices for this type of insulation can normally range from £7,000 to £15,000. It is usually installed in properties that have solid brick or concrete walls, but it can also be fitted to homes with cavity walls that are not suitable for cavity wall insulation. Installing solid wall insulation should save around £260 per year on the annual heating bills of a typical 3 bedroom semi-detached home. 

As external wall insulation will change the external appearance of the house, in most cases you will require planning permission before undertaking the work so you should check the requirements with your local authority before starting work. 

External Wall Insulation Grants Available 

Solid Wall Insulation Grants are available from the Government’s ECO Scheme for up to 25% of the cost. To qualify for Solid Wall Insulation Grants your home must have solid external brick or stone walls and you must receive one of the benefits outlined in the benefits section of this article. 

What Benefits Apply For Government ECO Energy Grants?

Within the summaries of the different types of insulation above, we have referred to government grants available under the Governments ECO scheme that are available to households throughout the UK. 

If anyone in your household receives a qualifying state benefit then you may be able to receive free home insulation and heating measures.

If you receive any of the benefits below, you could qualify for free insulation:

  • Armed Forces Independence Payment
  • Attendance Allowance
  • Carer’s Allowance
  • Constant Attendance Allowance
  • Disability Living Allowance (DLA)
  • Pension Credit Guarantee
  • Income-related Employment & Support Allowance (ESA)
  • Income-related Jobseeker’s Allowance (JSA)
  • Income Support
  • Industrial Injuries Disability Payment
  • Personal Independence Payment (PIP)
  • Severe Disability Allowance
  • Child Tax Credits.
  • Universal Credits
  • Working Tax Credits


If you are looking for ways to reduce heat loss and therefore save on the cost of energy bills for your home then you will be interested to know what are the different types of insulation available to you.

The different types of home insulation are: 

  • Cavity wall insulation
  • Loft insulation
  • Room in roof insulation
  • Internal wall insulation
  • External wall insulation

Most insulation methods will pay for themselves in as little as 5 years making them an excellent option to reduce the spiralling energy costs associated with heating your home. 

If you receive income-related benefits, have a household income below £31,0000 or are a homeowner or private tenant in the UK, then government grants under the ECO scheme are available to install cavity wall insulation, internal wall insulation, loft insulation, external wall insulation and room in roof insulation. 

All private UK homeowners, and some private tenants, who meet the eligibility criteria can qualify for new insulation. As long as you own your home or are privately renting, and the property is currently occupied, meaning it is not under renovation, you should qualify for an insulation grant.

To see if you qualify for a grant to insulate your home, the team at Free Insulation Scheme will be able to help you to apply for grants and arrange for the installation of the insulation at your home by regulated and accredited fitters. Simply call the team on 0330 470 116 or fill out the web form online

In this Article

Picture of Oliver Creevy

Oliver Creevy

Ollie has been writing content in the home improvement sector for over 3 years and over the last 18 months has really specialised in Government grants, researching the different funding available to UK citizens. Ollie is well placed to provide households with access to the right advice when it comes to improving the energy efficiency of your home. With knowledge of the various grant schemes past and present, including Boiler Upgrade Scheme, ECO4, LAD Scheme, Green Homes Grant and more, his knowledge will be invaluable to those looking for ways to reduce their energy bills and reduce their carbon footprint through eco home improvement measures such as solar panels, insulation & heat pumps.

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