What has changed
On 23 January 2026 the Department for Energy Security and Net Zero published its response on extending ECO4, the Energy Company Obligation that funds energy efficiency upgrades in lower-income homes. The scheme has been extended by nine months and now ends on 31 December 2026, rather than the 31 March 2026 date it was previously due to close on. ECO4 is the route that can put money towards measures including new glazing, so the extra time matters if you were hoping to use it. Our ECO4 guide covers how it works in full, and the wider double glazing grants page sets out every funding route alongside it.
Why it was extended
The reason given was practical rather than generous. The extra months let energy suppliers complete the targets they had already committed to, and, crucially, remediate non-compliant installations: work that was done to a poor standard the first time. That tidy-up followed scrutiny from the National Audit Office and the Public Accounts Committee. To keep the focus on finishing existing work, no new applications for Innovation Measures or Data Light Measures will be accepted during the extension.
For a sense of scale, around 949,800 measures have been installed in around 280,100 households under ECO4. That is a large programme to wind down cleanly, which is part of why the date moved.
There is no replacement coming
The bigger headline is what happens next, which is nothing in the same form. There will be no successor supplier obligation, a point confirmed at the November 2025 Budget. The model where energy suppliers fund upgrades to hit a target is being retired rather than renewed. The Great British Insulation Scheme, which ran alongside ECO4, still ends as planned on 31 March 2026, so it will close before ECO4 does.
Funding does not vanish, but it changes hands. After ECO4, support shifts to the council-run Warm Homes: Local Grant, topped up by £1.5bn of extra grant funding under the January 2026 Warm Homes Plan. If you rent out property, the direction of travel is also shaped by the EPC C rules landlords face by 2030, which will push many rentals towards better glazing whether or not a grant is available.
What it means if you want a grant
Eligibility under ECO4 is unchanged. It is aimed at households on income-related benefits, such as Universal Credit or Pension Credit Guarantee Credit, it is means-tested, and it can fund up to 100% of a measure. You cannot apply directly. You apply through a participating installer, who arranges a home assessment first. If you think you might qualify, the quickest way to find out is our grant eligibility checker, which walks you through the criteria in a few questions.
The honest framing is worth keeping in mind. Only around 15% of households qualify for grant funding of any kind, so for most people the practical question is what new windows actually cost. If you are likely to pay privately, price the job on that basis with our uPVC window calculator rather than waiting on a scheme you may not be eligible for.
If you genuinely qualify, do not sit on this. Find a participating installer and book the assessment now, because the queue gets longer as the deadline nears and there is no second scheme behind it to catch you. And if you do not qualify, stop waiting for funding and just price the work properly. That is what most homeowners end up doing anyway.
Tom Bradley, FENSA-registered installer
Frequently asked questions
ECO4 has been extended by nine months and now ends on 31 December 2026. The previous end date was 31 March 2026. The Department for Energy Security and Net Zero confirmed the change in its government response published on 23 January 2026.
No. There will be no successor supplier obligation. The decision not to run a follow-on scheme was confirmed at the November 2025 Budget, so once ECO4 closes the supplier-obligation model ends with it.
Funding shifts to the council-run Warm Homes: Local Grant, backed by £1.5bn of extra grant funding under the January 2026 Warm Homes Plan. Only around 15% of households qualify for grant funding of any kind, so most homeowners will still pay privately.
You cannot apply directly. You apply through a participating installer, who arranges a home assessment. Eligibility is means-tested and based on income-related benefits such as Universal Credit or Pension Credit Guarantee Credit, and it can fund up to 100% of a measure.