Tower Hamlets tops retrofit readiness league but most of UK lags behind

Just 1.3 million UK homes have an Energy Performance Certificate rating of C or above, out of 28 million. That is the gap the country needs to close. And according to a new study by Uswitch, one London borough is doing better than most: Tower Hamlets ranks first for ‘retrofit readiness’, based on loft insulation, cavity wall insulation, heat pump installations, and solar panel coverage.

The research, as reported by The Intermediary, analysed 10 indicators across local authorities and found Tower Hamlets with a score of 73 out of 100. The London average is 46. The national average is 42. That means most of the country is barely halfway to being ready for the mass home upgrade programme the government says it wants.

What ‘retrofit readiness’ actually measures

Uswitch used data from the Department for Energy Security and Net Zero and the Energy Saving Trust. The metrics include the proportion of homes with loft insulation (at least 200 mm), cavity wall insulation, solar photovoltaic panels, and heat pump installations per 100,000 households. Tower Hamlets scored well on insulation: 82% of its homes have loft insulation and 78% have cavity wall insulation. But the national picture is stark. Only 38% of UK homes have loft insulation to the recommended depth. Only 28% have cavity wall insulation. And heat pump installations remain a rounding error, fewer than 1% of homes have one.

For a homeowner in, say, a 1930s semi in the Midlands, the gap is personal. The Energy Saving Trust estimates that topping up loft insulation from 100 mm to 270 mm costs about £300–£400 and saves £180–£200 a year on heating bills. Cavity wall insulation costs around £700–£1,500 and saves £200–£300. These are the low-hanging fruit. Yet most homes haven’t picked them.

Why your EPC matters, and the 2028 deadline

From 2028, landlords in England and Wales will be banned from letting properties with an EPC rating below C. The cost of bringing a D-rated property up to C is typically £5,000–£15,000, depending on the work needed. That is a lot. But the alternative, a property that cannot be let, is worse. For owner-occupiers, the EPC is less of a legal stick but still a financial one: a home rated EPC C sells for 5–8% more than an equivalent EPC D, according to Nationwide.

The catch is that grants are patchy and confusing. The Boiler Upgrade Scheme offers £7,500 off a heat pump, but only for homes that have already improved insulation. The ECO+ scheme targets low-income households and those in the least efficient homes (EPC D or below). Yet take-up has been slow: Ofgem data shows only 12,000 heat pump grants were claimed in the first six months of 2024. The government’s own advisers at the Climate Change Committee say the UK needs 600,000 heat pump installations a year by 2028. The gap between ambition and delivery is huge.

What you can do now, without waiting for a grant

Start with an EPC assessment. It costs £60–£120 and gives you a baseline. Then check your loft insulation depth, most DIY stores sell a £5 tape measure. If it is below 270 mm, top it up. Check whether your cavity walls are filled, a surveyor can tell you in minutes. These two measures alone can lift a typical D-rated home to a C, cutting annual bills by £300–£500. Solar panels are next: a 4 kW system costs about £6,000–£8,000 and saves £500–£700 a year, but only if your roof faces roughly south and isn’t shaded.

Uswitch’s study is useful as a benchmark. But the real lesson is not that Tower Hamlets is doing well, it is that the rest of the country is doing poorly. For the average homeowner, the path is clear: insulate first, then electrify. And start before the 2028 deadline hits, because contractors will be booked solid.