ECO4 billions spent but UK homes still leak heat

£1.2 billion has been spent on energy efficiency upgrades under the Energy Company Obligation (ECO4) since 2022, yet the National Audit Office (NAO) reports that only 200,000 homes have received measures. That is roughly one in every 140 households in England, Scotland and Wales. For the average UK homeowner, the question is not abstract: why is so much public money delivering so little visible progress on your street?

As reported by the National Audit Office, the programme is on track to meet its overall target of 450,000 homes by 2026. But the pace suggests many households will wait years for upgrades, if they qualify at all.

Who qualifies, and who doesn’t

ECO4 is not for everyone. It targets low-income households, those receiving means-tested benefits, and properties with an EPC rating of D, E, F or G. If you live in a three-bed semi with an EPC band C and earn above the threshold, you are not eligible. The NAO report notes that 40% of eligible homes have not yet been reached, roughly 1.6 million properties. For those who do qualify, the scheme covers loft insulation, cavity wall insulation, solid wall insulation, and in some cases, heat pumps or solar panels. The catch is that installation depends on your energy supplier’s obligation, not your own application. You cannot simply call up and book a date; you must be referred through a local authority or registered installer.

What it costs a typical 3-bed semi

The NAO figures show the average cost per household is around £6,000. For a typical semi-detached home using 12,000 kWh of gas per year, loft insulation alone can save around £200 annually, while solid wall insulation can save up to £400. But these savings assume the work is done properly. The report flags concerns about installation quality, some homes received measures that failed to perform as expected. Ofgem, which oversees ECO4, has issued compliance notices to several suppliers. For the homeowner, this means checking the installer’s accreditation and asking for a post-installation assessment. The Energy Saving Trust recommends a full home survey before any work begins.

The gap between target and reality

The NAO report calculates that at the current rate, ECO4 will miss its 2026 target by about 50,000 homes. The reasons are familiar: supply chain delays, a shortage of trained installers, and the complexity of assessing older properties. But the bigger picture is that the UK’s housing stock remains among the least efficient in Europe. The government’s own figures show that 13 million homes still have an EPC rating of D or below. For every £1 spent on ECO4, the Treasury estimates £1.50 in health and energy bill benefits over the long term. Yet the programme is built to help the poorest households, those least able to afford the upfront cost of insulation. If you are eligible, the message is clear: apply now, because the window is finite. The scheme closes to new applications on 31 March 2026, though installations can continue until 2027.

What this misses is the 80% of UK homes that do not qualify for ECO4. For them, the government offers the Great British Insulation Scheme, which provides partial funding for loft and cavity wall insulation. But the budget is smaller, around £1 billion over three years, and the per-home spend is lower. The practical advice for any homeowner is to check your EPC rating first. If it is below C and you are on a low income, contact your energy supplier. If not, consider a home energy audit from a certified assessor; the cost of £100–£200 is often recouped in the first year of lower bills.