British Gas Free Loft Insulation: How Supplier Offers Work

People search for “British Gas free loft insulation”, “E.ON free loft insulation” and similar every month, usually after seeing an advert or getting a letter. The offers are real in the sense that the big suppliers do pay for loft insulation. What they are not is a customer perk, a universal offer or a promise. This guide explains how supplier-funded loft insulation works, who it is for, and how to check an offer.

Why energy suppliers pay for loft insulation

Under the Energy Company Obligation, medium and large energy suppliers are legally required to fund energy-saving measures in lower-income and vulnerable households. ECO4, the current phase, runs until 31 December 2026 after a nine-month extension, and Ofgem says suppliers must deliver their obligations in full by then. The more customers a supplier has, the bigger its share of the obligation.

So when a household name offers free loft insulation, it is usually meeting that legal duty, either directly or through installers it funds. That is why an offer that mentions British Gas or another supplier may arrive from a company you have never heard of.

You do not have to be their customer

Ofgem says you can contact any of the obligated energy suppliers to find out how they may be able to help you, even if they are not your energy provider. Ofgem publishes the list of participating suppliers and their contact details. If one supplier cannot help, another might.

Who supplier-funded loft insulation is for

The same rules apply whichever supplier you approach, because they all deliver the same scheme:

• someone in the household receives a qualifying benefit (GOV.UK lists Universal Credit, Pension Guarantee Credit, Pension Savings Credit, Income Support, income-based Jobseeker’s Allowance, income-related Employment and Support Allowance, Child Benefit and Housing Benefit), or your council refers you through LA Flex, for example on household income under £31,000;
• the home is rated EPC D, E, F or G if you own it, or E, F or G if you rent privately (with the owner’s permission);
• the home is in England, Scotland or Wales. ECO4 does not apply in Northern Ireland.

Supplier offer says	What it really means
“Free loft insulation”	Funded through ECO4 if you meet the rules
“Only for existing customers”	Any eligible household can approach any obligated supplier
“Limited places”	Suppliers must finish by 31 December 2026; capacity varies
“No cost to you”	Usually; Ofgem notes some households are asked to contribute

Not a grant, and not always entirely free

Ofgem describes ECO as not a grant scheme, which is why different suppliers may offer different levels of support, and says that in some cases you may be asked to contribute to the cost of the installation. Ask the question plainly before any work is agreed, and get the answer in writing.

What about Octopus, OVO and the others?

Any supplier with an ECO4 obligation works the same way. We do not list which suppliers are taking new ECO4 loft jobs at any moment, because that changes and only the suppliers know their remaining capacity. Contact them directly using Ofgem’s supplier contact list.

How to check a supplier offer

1. Ask the company that contacted you which supplier is funding the work.
2. Contact that supplier yourself, using the details on its own website or Ofgem’s list, and ask whether the offer is genuine. GOV.UK recommends exactly this.
3. Check the installer on the TrustMark register.
4. Never pay a fee to reserve a place.

If you do not qualify for ECO4, England’s Warm Homes: Local Grant, the Scottish, Welsh and Northern Irish schemes, or paying yourself (the Energy Saving Trust puts a bare semi-detached loft at about £750) are the alternatives. See who qualifies, ECO4 loft insulation and government schemes compared.

After 31 December 2026

The Warm Homes Plan says the Energy Company Obligation is coming to an end, with low-income support moving to government-funded schemes. Supplier-funded loft insulation, as it works today, has a limited life. Read loft insulation after ECO4.

What happens after you say yes

A supplier-funded loft job follows the ECO4 process whichever brand is behind it. An assessor visits to rate the home, because eligibility and the package of measures both depend on the result. For loft work, the installer and the occupier (or landlord) sign a pre-existing loft declaration recording what insulation was already there, and a copy is fixed near the loft hatch. The installation itself is usually a day’s work for a straightforward loft: clearing the access route, laying mineral wool between and across the joists to around 270mm, keeping the eaves clear and lagging pipes and tanks.

Keep the paperwork. If something goes wrong later, GOV.UK says to contact the installer or the company that guaranteed the work first, and Citizens Advice if the problem is not solved. Ofgem publishes supplier contact details so you can also raise concerns with the supplier that funded the job.

A supplier letter is not a decision

Some households receive letters or emails from their own supplier mentioning ECO4. These can be genuine, and they are a sensible place to start if you think you qualify. But the letter does not mean you have been approved: the assessment decides. Equally, not receiving a letter does not mean you are not eligible. If you meet the benefit or LA Flex rules and your home’s EPC band fits, you can approach an obligated supplier yourself.

Sources: GOV.UK ECO · Ofgem ECO homeowners and tenants · Ofgem ECO · Warm Homes Plan — all read 29 September 2026.