Ofgem’s October price cap will land hardest on Britain’s draughtiest homes. New analysis, as reported by London TV, shows households in EPC-banded F and G properties will pay up to £591 more a year under the new cap. That is more than six times the £89 increase for homes rated A. The price cap itself is not discriminatory, the physics of heat loss is.
Why the gap is widening
The October cap sets a maximum unit price for gas and electricity: roughly 24.5p per kWh for electricity and 6.2p per kWh for gas, according to Ofgem’s latest figures. But the total bill depends on how much energy a home needs. A typical G-rated semi-detached house uses about 18,000 kWh of gas a year, while an A-rated equivalent uses around 8,000 kWh. The cap rise multiplies that difference. The Energy Saving Trust estimates that draught-proofing alone can save a typical home £60 a year. For an F-rated property with single glazing and no loft insulation, the savings from basic upgrades stack quickly.
Who qualifies, and who doesn’t
The £591 figure assumes a property with the highest energy use profile under the cap. Most homes fall in the D or E band, where the extra cost is roughly £200–£300 a year. That is still painful, but it shows a bigger point: EPC ratings are not abstract letters on a certificate. They are a direct predictor of annual running costs. The government’s Boiler Upgrade Scheme offers £7,500 towards a heat pump, but only for homes with a valid EPC and no outstanding cavity wall or loft insulation recommendations. Low-rated homes often need fabric upgrades first, insulation, glazing, ventilation, before they qualify for the heat pump grant.
What it costs a typical 3-bed semi
Take a 1960s semi in the Midlands with an EPC of F. It has single glazing, 50mm loft insulation, and a 15-year-old gas boiler. The October cap means its annual gas bill rises by about £340, electricity by another £150, total £490 extra. The same house upgraded to a C rating, with double glazing, 270mm loft insulation, cavity wall fill, and an A-rated boiler, would see only a £120 increase. The upfront cost of those upgrades runs £5,000–£8,000, but the payback comes in under four years from avoided energy bills. The catch is that many households cannot front that capital. The Great British Insulation Scheme offers free or subsidised loft and cavity wall insulation for low-income homes, but take-up has been slow: only 45,000 homes had received measures by mid-2024, against a target of 300,000.
What you can do now
Check your EPC at gov.uk/find-energy-certificate. If you are band E or below, start with the cheapest fix: loft insulation top-up. A 270mm layer costs £300–£500 and can save £180 a year. Next, cavity wall insulation (£500–£1,500) and draught-proofing (£200). For homes off the gas grid, a heat pump becomes viable after fabric improvements. The October cap rise is fixed, but your home’s energy demand is not. Every kilowatt-hour you do not use is one you do not pay for.
Frequently Asked Questions
Yes, typically within one billing cycle after the upgrade is installed. Insulation and draught-proofing reduce heat loss, so your boiler or heat pump runs less. The savings are biggest in winter. You should see a 15–30% drop in gas use after loft and cavity wall insulation.
Yes, the Great British Insulation Scheme and Energy Company Obligation (ECO4) provide free or subsidised insulation for eligible households. Check your eligibility at gov.uk. The Boiler Upgrade Scheme also covers heat pumps, but only if your EPC has no outstanding insulation recommendations.
