Solar deals with your electricity. For most British homes, the bigger energy cost is heating, and the large majority of homes heat with gas. A heat pump is the way solar reaches that part of the bill.
This section is written straight, including the parts that are awkward.
What a heat pump is
A heat pump moves heat rather than making it. It takes low-grade heat from the outside air or the ground and raises it to a useful temperature for your radiators, underfloor heating and hot water. It runs on electricity.
Because it moves heat rather than burning fuel, it delivers more heat energy than the electrical energy it uses. Typically three or so units of heat per unit of electricity, which is where the efficiency argument comes from.
Two types matter for most homes:
- Air source, taking heat from outside air. The common choice.
- Ground source, taking heat from the ground through buried pipework. More efficient, considerably more expensive, and needs land.
There is also air-to-air, which heats the air directly rather than water. It does not provide hot water, but it is much cheaper to fit and it can cool in summer. It suits flats and small houses that cannot take a wet system.
What it costs
| Air source heat pump, installed, before grant | £11,500 to £15,500 |
| After the Boiler Upgrade Scheme grant | £4,000 to £8,000 |
| Air-to-air heat pump grant | £2,500 off the installed price, England and Wales |
The Boiler Upgrade Scheme pays £7,500 in England and Wales, or £9,000 for eligible properties off the gas grid until 31 Mar 2027. Your installer applies and takes it off the price. You do not apply and you do not wait for a refund. Scotland has its own, more generous scheme.
Full detail: the Boiler Upgrade Scheme.
Prices are indicative ranges, last reviewed 6 Nov 2026.
Will it cost more to run than my gas boiler?
The honest answer is: at current prices, probably about the same, and the difference depends on how well it is installed.
Electricity costs about 26.32p per unit and gas about 7.97p, so electricity is roughly three and a third times the price. A heat pump has to be at least that much more efficient than your boiler to break even.
The break-even is a seasonal performance factor of about 2.81. The median across 291 systems in a UK field trial was 2.8.
So a typical installation roughly breaks even. A well-designed one running low flow temperatures saves meaningfully. A poor one costs more.
We would rather tell you that than tell you heat pumps always save money, because they do not, and you would find out afterwards. The full arithmetic, including the gas standing charge, is on heat pump running costs.
Where solar changes the picture
This is the part that matters on this site.
A heat pump is a large, year-round electricity load. Solar reduces the price you effectively pay for the electricity it uses, and it raises the share of your own generation you use at home rather than export, which is the single biggest factor in whether solar pays.
The two together work better than either alone, and that is not a sales line, it is the arithmetic. See solar and a heat pump together.
Does your home suit one?
The old rule that you needed to insulate first has changed. The energy performance certificate (EPC) insulation prerequisite for the Boiler Upgrade Scheme was removed in 28 Apr 2026.
What actually matters:
- Radiator sizing. A heat pump runs at a lower flow temperature than a boiler, so radiators often need to be larger. This is the most common piece of additional work.
- Space outside for the external unit. Under permitted development in England the outdoor unit must not exceed 1.5 cubic metres on a house.
- Somewhere for a hot water cylinder, if you currently have a combi boiler and no cylinder. This catches people out.
- A reasonable level of insulation. Not a legal requirement any more, but it still determines whether the system performs well.
Heat pumps or a new boiler?
If you are weighing a heat pump against a replacement gas or oil boiler, our sister site Boiler Market UK covers replacement boilers and is the better place to compare that side properly. We cover heat pumps. Between us you can see both cases honestly rather than each site arguing for the thing it sells.