Heat pump running costs: 3-bed detached house
About £666 to £895 a year, compared with £1,224 for a gas boiler.
How efficiency changes the cost
| Heat pump efficiency | Electricity used | Standard tariff | Cosy Octopus | vs gas* |
|---|---|---|---|---|
| Typical UK install (2.8) | 4,250 kWh | £1,119 | £832 | saves £392 |
| Good install (3.5) | 3,400 kWh | £895 | £666 | saves £558 |
| Excellent install (4.2) | 2,833 kWh | £746 | £555 | saves £669 |
*Cosy Octopus cost compared with a gas boiler at £1,224 a year (14,000 kWh of gas at 7.97p plus the standing charge). Typical figures for a 3-bed detached house; yours will vary.
What this means for a 3-bed detached house
A typical 3-bed detached house uses about 14,000 kWh of gas a year for heating and hot water. That is roughly 11,900 kWh of useful heat. A heat pump delivers the same heat using far less energy, but electricity costs more per kWh than gas, so the result depends on how efficient the system is and which tariff you’re on.
The tariff matters as much as the heat pump. On a standard tariff this home would pay about £895 a year. Scheduling the heat pump around Cosy Octopus’s cheap windows brings that down to about £666. How Cosy works →
FAQs
How much does it cost to run a heat pump in a 3-bed detached house?
About £895 a year on a standard tariff, or about £666 on a heat pump tariff such as Cosy Octopus, for a good installation (SCOP 3.5).
Is that cheaper than gas for a 3-bed detached house?
A gas boiler in a typical 3-bed detached house costs about £1,116 a year in gas, or £1,224 including the gas standing charge. So a well-installed heat pump on a heat pump tariff should cost about £558 a year less to run.
How much electricity will a heat pump use in a 3-bed detached house?
Roughly 3,400 kWh a year at SCOP 3.5, to deliver about 11,900 kWh of heat.
Run your heat pump on cheaper electricity
Cosy Octopus has three cheap windows a day, priced 51% below its day rate. Switch through our referral link and you also get £50 credit.
Get an Octopus Quote + £50 Credit →You need a heat pump and a smart meter. Link checked 5 October 2026.