Ofgem reports that 4.3 million UK homes still have uninsulated pitched roofs. This means significant heat is lost through the roof, leading to higher energy bills and a less comfortable home. The UK government is prioritising treating the worst-performing homes first to reduce carbon emissions.
This article explains who qualifies for a roof insulation grant in 2026, specifically for the method known as roof insulation between rafters. It covers the eligibility rules, typical costs, and the steps you need to take to apply.
Who qualifies for a roof insulation grant in 2026
You may qualify for a grant under the Energy Company Obligation (ECO4) scheme if you meet three main conditions. The first route is receipt of a qualifying means-tested benefit, such as Pension Credit, Universal Credit, or Income Support (GOV.UK, Energy Company Obligation (ECO4): guidance for households, 2026).
The second route is having a low household income and a valid referral from a local authority or health professional. The third condition is that your home must have an Energy Performance Certificate (EPC) rating of D, E, F, or G. The grant typically covers 100% of the cost for eligible households, but only for insulation that meets a minimum thickness or U-value standard.
Quick numbers, what a 100mm and 150mm roof insulation grant covers
| Insulation thickness | Typical U-value achieved | Typical cost per m² (installed) | Grant coverage for eligible households |
|---|---|---|---|
| 100mm mineral wool | 0.35 W/m²K | £25 | Full cost if meets standard |
| 150mm mineral wool | 0.25 W/m²K | £35 | Full cost if meets standard |
| 100mm PIR board | 0.22 W/m²K | £45 | Full cost if meets standard |
| 150mm PIR board | 0.15 W/m²K | £60 | Full cost if meets standard |
U-value is a measure of how well a material prevents heat from passing through. A lower U-value means better insulation. Costs are based on Energy Saving Trust data and MCS installer database averages (Energy Saving Trust, Insulation materials and their U-values, 2026). Grants cover the full cost only if the installation meets the required standard. Partial grants may apply for better-performing materials.
Roof insulation between rafters is a method for insulating the sloped roof of a pitched roof home
Roof insulation between rafters is a method where insulation is fitted between the sloping timbers (rafters) of a pitched roof. This is different from loft insulation, which is laid on the floor of the loft space. It is also different from rigid board insulation applied to the roof deck.
This method is typically used when the loft is habitable or when the roof is the main heat loss area. It is the method most commonly covered by ECO4 grants for pitched roofs. The insulation can be installed from inside the loft or from the roof surface, depending on access.
Eligibility for grants, who is excluded and why
Some households are excluded from roof insulation grants. These include homes with an EPC rating of A, B, or C, as these are already well-insulated. Also excluded are homes with a valid loft insulation exemption, and homes that have received a grant for the same measure in the last five years (Ofgem, ECO4: eligibility and exclusions, 2026).
Grant funds are targeted at the worst-performing homes to maximise carbon savings. Homes with flat roofs are also excluded, as the method is only suitable for pitched roofs. Homes where the rafters are less than 100mm deep are excluded because insulation cannot achieve the required U-value.
How to verify an installer, the certification you must check
If you receive a grant, the installation must be carried out by an MCS-certified installer. You can check the installer’s MCS certificate number on the MCS website (MCS, 2026). For non-grant work, TrustMark is the recommended quality mark for insulation installers (TrustMark, 2026).
Gas Safe registration is only relevant if the work involves moving or altering gas pipes. Always verify certification before work begins to ensure the installation is eligible for the grant and meets the required standard.
How to confirm your eligibility, the step-by-step process
Start by checking your EPC rating at gov.uk/find-energy-certificate. If your rating is D, E, F, or G, you are likely eligible. Next, check if you receive a qualifying benefit such as Pension Credit, Universal Credit, or Income Support (GOV.UK, Find out if you can get help with energy bills and home improvements, 2026).
Contact your energy supplier or a local authority scheme to apply. The supplier will arrange a survey to confirm the roof is suitable and the insulation meets the standard. If approved, the supplier arranges the installation at no cost to you.
Guide to checking your EPC rating
How ECO4 grants work for other insulation types
Frequently Asked Questions
Yes, if you receive a means-tested benefit like Pension Credit or Universal Credit, or have a low income with a local authority referral, and your home has an EPC rating of D-G. Ofgem administers the ECO4 scheme.
Costs range from £25 per m² for 100mm mineral wool to £60 per m² for 150mm PIR board, based on Energy Saving Trust data. Grant coverage may fully cover these costs for eligible households.
A U-value of 0.15-0.35 W/m²K is typical, depending on insulation thickness and material. The lower the U-value, the better the insulation performance, as confirmed by MCS standards.
Yes, but grant-funded work must be installed by an MCS-accredited professional to meet building regulations and qualify for ECO4 funding. DIY installation may not achieve required U-values.
Roof insulation between rafters typically lasts 40-50 years if properly installed and maintained. Mineral wool and PIR boards both have long lifespans, according to the Energy Saving Trust.
