Savings are possible, but not automatic. The electricity-to-gas price ratio and your installed system's seasonal performance matter more than a generic savings claim.
One home, three plausible outcomes
Suppose a home needs 10,000 kWh of useful heat each year. An 85% efficient gas boiler would use about 11,765 kWh of gas. Using Ofgem's October to December 2026 average Direct Debit unit rates of 7.97p per kWh for gas and 26.32p for electricity, that is about £938 of gas for heat.
At a seasonal performance factor of 2.8, a heat pump would use about 3,571 kWh of electricity, costing about £940. At 3.1, it would use about 3,226 kWh and cost about £849. At 3.5, it would use about 2,857 kWh and cost about £752. The same heat demand therefore spans near parity to a saving of around £186 in this example.
This is a unit-rate illustration, not a forecast. It excludes standing charges, tariff changes through the year, servicing, hot-water differences, gas used for cooking and any new electricity tariff. The Ofgem figures are a snapshot, so update them before making a decision.
The quick test: price ratio versus performance
With those Ofgem rates, electricity costs about 3.3 times as much per kWh as gas. A heat pump does not need to be 3.3 times as efficient as the boiler, because the boiler loses some energy. Against an 85% efficient boiler, the heat pump breaks even on the two unit rates at a seasonal performance factor of about 2.8. This is the useful comparison that a simple 'heat pumps are cheaper' headline misses.
Energy Saving Trust says seasonal performance can vary considerably with design and operation. Request a property-specific estimate and ask whether the installer has included hot water, backup heater use and your likely flow temperature.
When removing gas changes the result
Ofgem's average gas standing charge for October to December 2026 is 29.68p a day. Closing a gas connection that you no longer need could avoid roughly £108 over a year at that rate. If you still use gas for a hob or another appliance, you will usually keep paying the standing charge.
Households on a suitable heat pump tariff may pay less for some electricity, but their total bill depends on when the heating, hot water and other appliances use power. Ask for a comparison using your tariff and recent energy bills.
Efficiency also depends on comfort
Heat pumps often run for longer at a lower water temperature than a boiler. A good design matches emitters and controls to the rooms so comfort does not depend on turning the flow temperature up unnecessarily. Insulation and draught reduction lower the heat needed in the first place, though the IEA notes that heat pumps can still deliver major energy savings in poorly insulated homes.
A note about the numbers
Prices, grants and tariffs can change. The dated figures above come from the linked sources and are examples unless explicitly described as a published average. Your installer should assess your property before giving a final design or quotation.