New boiler or heat pump: how to decide

The answer for a typical home

For a home in Ofgem's North West region, paying by direct debit and using Ofgem's typical 9,500 kWh of gas a year, our result is: Similar running costs.

The typical results below show the figures for every region.

From Chris's work as a heat networks and energy manager: If it’s safe, reliable and doing its job, keeping it for now can be a sensible decision. That’s particularly true if money is tight, building improvements are planned or the heat pump proposal hasn’t been properly worked through. I’d use that time to plan the replacement so the decision isn’t forced when the boiler fails.

Why the price of electricity decides it

The result depends on the price of electricity compared with gas, not on how much gas you use. These rates assume gas at the price cap's maximum, and include VAT.

In Ofgem's North West region, paying by direct debit: below 24.5p per kWh, most measured heat pumps would cost less to run than a gas boiler. Above 29.5p, most would cost more. The cap's maximum electricity rate there is 26.49p.

What the figures leave out

A grant can lower the installation cost. In England and Wales, GOV.UK says you may be able to get £7,500 from the Boiler Upgrade Scheme towards an air source heat pump if you own your home and are replacing fossil fuel heating.

The running cost figures leave out standing charges, installation cost, grants and maintenance.

From Chris's work as a heat networks and energy manager: It’s the work around the heat pump: radiator changes, pipework alterations, a suitable hot water cylinder, electrical work, the outdoor base and drainage. Access and making good afterwards can add to the job as well. I’d want an itemised quote showing what’s included and what could become an extra.

What can change the answer for your home

Heat pumps in real homes vary. The middle half of the 428 homes measured made between 2.62 and 3.15 units of heat per unit of electricity. A heat pump at the poorer end of that range costs more to run than the typical figure.

From Chris's work as a heat networks and energy manager: Poor heat loss assumptions, radiators that need hotter water than allowed for, unsuitable pipework and controls that cause frequent stopping and starting. Commissioning and handover matter as well. I’d want those things investigated before accepting that the heat pump itself is the problem.