The essential guide to installing insulation

As winter approaches, many homeowners will be looking to keep their energy costs as low as possible, especially as fuel prices are still relatively high. Improving energy efficiency by improving or installing insulation is one way to do this, so offering this service could boost your business.

With gas boilers being phased out as part of the government’s Net Zero strategy, homeowners will need to switch to low-carbon heating systems such as heat pumps. Since these work best in well-insulated homes, demand for insulation will only increase further. You can read more about this in our home energy technologies guide.  

Homes produced 17% of the UK’s carbon emissions in 2022 – mostly from gas used for heating, hot water and cooking – so making homes more energy efficient is essential if the government is to achieve its aim of reaching net zero by 2050.

Government schemes

The government launched two key schemes to help homeowners, landlords and tenants improve the insulation of their properties. 

The Great British Insulation Scheme, launched in September 2023, offers free or cheaper insulation measures - including cavity wall, roof and loft insulation - to households in lower council tax bands with an Energy Performance Certificate rating of D or below. 

The Home Upgrade Grant offers support to off-the-grid homes that do not rely on a gas boiler to heat their homes, and have  an EPC rating of D to G. Support can range from insulation and draft proofing to new windows and doors, as well as the installation of heat pumps and solar panels.

Both of these build on the Energy Company Obligation (ECO), which requires the largest energy companies to help certain households on lower incomes with the financial cost of energy-saving measures such as installing insulation and boiler replacement. 

Types of insulation

There’s a range of insulation that can be retrofitted to homes to make them more energy efficient. These include:

• Cavity wall insulation – homes built after the 1920s but before the 1990s are likely to have cavity walls with no wall insulation. Insulation material is injected into the cavity through holes that are drilled and then sealed.
• Solid wall insulation – homes built before the 1920s are likely to have solid walls. There’s no cavity to inject insulation into but the walls can be insulated internally or externally.
• Floor insulation – the ground floor of homes or floors above unheated spaces such as garages can be insulated to keep more heat in. Insulation can be laid between the joists of suspended timber floors. Concrete floors can have rigid insulation board laid on top.
• Roof and loft insulation – insulation can be laid over and between the joists in lofts with another layer on top to make it deep enough while flat roofs can be insulated from above with rigid insulation boards.
• Draught proofing – gaps, such as around doors and windows, are blocked up to stop unwanted cold air getting in and warm air escaping. Open chimneys can also be draught proofed. Although many homeowners choose to draught proof their homes themselves, others opt for professional draught proofing, which is likely to be more effective.

Spray foam insulation can be used to insulate roofs, lofts, walls and floors instead of traditional insulation materials, but it has a number of drawbacks. Read our guide to spray foam insulation to find out more.

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Becoming an installation installer

Depending on what stage of your career you’re at, there are three ways you can become an insulation installer: through taking college courses, an apprenticeship or – if you have the necessary experience and qualifications – applying for a job directly.  

If you work in the building trade and already have relevant knowledge and skills, there are a number of NVQ (NVQ) courses you can take to boost your skills and demonstrate to customers that you have insulation expertise. These include six Level 2 Insulation and Building Treatments NVQs covering:

• wood preserving and damp proofing
• wall tie replacement
• cavity wall insulation
• solid floor insulation
• under floor insulation
• cold roof insulation. 

There are also eight Level 3 NVQs you can take if you have existing knowledge and skills at a higher level. These are:

• room in roof
• park homes
• hybrid wall
• insulating framed sections of buildings
• external wall insulation – finisher
• external wall insulation – boarder
• external wall insulation – boarder and finisher
• internal wall insulation

Boost your business

To get established in the insulation installation business or increase your success in this area it’s important that potential customers have trust in you and your business. Having qualifications is one way to do this but there are others.

Boost your reputation by providing a great service every time so previous customers recommend you to others. Building a rapport, being responsive  and being transparent at all stages of the process will also help you build trust. And if something does go wrong, do everything you can to put things right as quickly as possible.

Good reviews will convince many potential customers to choose you, so building up a decent number of these will go a long way towards boosting your insulation business. Ask satisfied customers to leave reviews and always respond to any negative ones that have been posted. 

If you’re a Which? Trusted Trader, we check all the reviews posted about you on your profile page to make sure they’re genuine.