Improve your insulation and windows

Better insulation and windows can save on energy bills and lower carbon emissions. Government loans and grants are available to help with upfront costs.

Making improvements as a business

Replacing insulation and windows is a common household building improvement.

Businesses can also take advantage if they are located inside a home or another type of building they are allowed to renovate.

The Carbon Trust has a building fabric guide to help businesses decide if they need better insulation.

Get approval for your building

To improve insulation and windows at your business, you must:

  1. Own the building or get permission from the landlord to make changes.
  2. Get permission from the local council if the building is listed or in a conservation area.
  3. Leave the affected part of the building while work is being done.

Most upgrades will take 1 to 2 days if done by a professional.

What upgrades to make

To save on running costs and reduce emissions you need to lower energy use as much as possible. The potential savings are highest if your building has:

  • poor or no loft insulation
  • cavity walls that can be injected with insulation
  • older single-pane windows

Smaller projects such as sealing draughts can make your building more comfortable but will not result in significant savings.

Loft insulation

Adding loft insulation is one of the most effective ways to lower energy costs. It can pay for itself in as little as 2 years and can remain in place for up to 40 years.

For a detached building the average install cost is £395 for an annual savings of £250.

Visit the Energy Saving Trust website to find costs for different building types and insulation materials.

Cavity wall insulation

Buildings constructed between 1920 and 1990 often have an empty space between the exterior and interior walls. Insulation can be injected into these ‘cavity walls’ through exterior holes. It can pay for itself in 3 to 5 years.

For a detached building the average install cost is £610 for an annual savings of £280.

Visit the Energy Saving Trust website to learn how to identify cavity walls and different options for insulating them.

Solid wall insulation

Buildings constructed before 1920 often have ‘solid’ walls with no cavity. Insulation can be installed on top of existing walls and ranges from £8,000 to £10,000 for an entire semi-detached building.

With an estimated annual savings of £375 it can take over 20 years to pay for itself. Installation is more intrusive and likely to take longer than loft or cavity wall insulation.

Visit the Energy Saving Trust website to find different installation options and who to hire.

Double glazed windows

If your business has single pane, aluminum frame or other types of older windows, replacing them with double glazed windows can save up to £120 per year.

With the minimum cost for each window around £500 it can take at least 10 years to pay for itself.

Visit the Energy Saving Trust website to find information on window types and who to hire.

Government grants

Most business grants are provided by local councils. UK-wide grants such as the Green Homes Grant and Energy Company Obligation apply to homes only.

Local council grants

Use a postcode checker to find out what is available from your local council.

Green Homes Grant scheme

Covers two-thirds of the cost of new insulation and windows up to £5,000. Applies to homeowners, long-leaseholders and residential landlords.

Find full details on GOV.UK. The 2021 application deadline has passed.

Energy Company Obligation (ECO)

The ECO scheme provides discounts on loft and cavity wall insulation to lower income households. Take a survey to see if you qualify.

Get government advice

Due to the number of grants available and the differences in building types, it can be helpful to speak to a government advisor about your needs.

In England and Wales

Call Simple Energy Advice at 0800 444 202. It’s open Monday to Friday, 8am to 8pm.

In Scotland

Call Home Energy Scotland at 0808 808 2282. It’s open Monday to Friday, 8am to 8pmand Saturday, 9am to 5pm.