More than half of homes in England and Wales sit at EPC D or below, that is roughly 14 million properties, each leaking heat and burning cash. The figure, published by The Intermediary and based on government data, lands as the price cap rises again in October. For a typical 3-bed semi on a standard variable tariff, that means an extra £63 a year on top of already painful bills.
As reported by The Intermediary, the data shows a stark north-south divide: London has the highest share of A-C rated homes, while Wales and the North East lag behind. The gap is linked to geography, money, tenure, and the age of the housing stock.
Who qualifies, and who doesn’t
Owner-occupiers in poorly rated homes can act fastest. They control the walls, loft, and boiler. But the data shows that private rented homes are also heavily represented in the D-and-below cohort. Landlords face a legal minimum of EPC E from 2025, with proposals to raise that to C by 2030. That deadline is tightening, and the cost of non-compliance, fines up to £30,000, is now a real risk for portfolio landlords.
Social housing performs better, but still a third of council and housing association homes sit below C. The biggest blocker is not willingness: it is the upfront cost. A full retrofit for a solid-wall Victorian terrace can run £15,000 to £30,000. For many households, that sum is simply not available.
What it costs a typical 3-bed semi
The Energy Saving Trust estimates that moving from an EPC D to a C saves about £300 a year on gas and electricity for a gas-heated semi-detached home. That is real money, but the payback period for cavity wall insulation alone is typically 2 to 4 years, and for a new heat pump, closer to 10 years with grants.
Grants do exist. The Great British Insulation Scheme offers free or discounted cavity wall and loft insulation to households on certain benefits or with low EPC ratings. The Boiler Upgrade Scheme gives £7,500 off an air-source heat pump. But take-up has been patchy. Ofgem data shows only about 30,000 heat pump vouchers were redeemed in the first year of the scheme, a fraction of the 600,000 annual target the government once set.
The catch is that many households do not know they qualify. A survey by Citizens Advice last year found that 4 in 10 low-income households had never heard of the main energy-efficiency grants. The government’s own marketing has been modest, and local authority schemes vary wildly.
What the EPC data actually measures
An EPC rating affects bills, mortgage options, resale value, and rental income. Since 2021, some lenders have offered green mortgages with lower rates for homes rated A or B. A few, like Nationwide and Barclays, now also lend more cheaply for C-rated homes. The difference is small, typically 0.1 to 0.2 percentage points, but on a £200,000 mortgage that saves £200-£400 a year.
Yet the rating system itself has flaws. It assumes standard occupancy and heating patterns, so a well-insulated home with an inefficient oil boiler can still score poorly. And it does not account for smart controls, solar panels, or battery storage in the same way a bill-based assessment would. The government consulted on reforming EPCs in 2023 but has not yet published final proposals.
Households on standard variable tariffs should check their EPC on gov.uk using their postcode. If it is D or below, the next step is to book a free home energy assessment from a local advice centre or via the Energy Saving Trust. Grants for insulation and heating upgrades are open now, but many close when funding runs out. The time to apply is before winter, not during it.
Frequently Asked Questions
Costs vary widely by property type. For a typical 3-bed semi with cavity walls, loft insulation, and a modern gas boiler, the upgrade might cost £2,000-£5,000. Solid-wall homes or those with electric heating can cost £10,000-£20,000. Grants can cover some or all of this for eligible households.
From 2025, all rented homes in England and Wales must have a minimum EPC rating of E. Proposals to raise the minimum to C by 2030 are under consultation. Landlords who fail to comply can face fines of up to £30,000.
