Enter your home's annual heat demand, a heat pump's seasonal efficiency (SCOP) and the energy prices, and this compares the yearly running cost of a heat pump against a gas boiler. A higher SCOP means more heat per unit of electricity.
A heat pump uses electricity, which is dearer per unit than gas, but it is far more efficient: a SCOP of 3.5 means it delivers 3.5 units of heat for every unit of electricity, where a gas boiler delivers under 1. Whether it works out cheaper depends on the gap between electricity and gas prices and on the SCOP you actually achieve, which is why a well-designed system at a low flow temperature matters. The sums here are illustrative; for the detail see heat pump running cost vs gas boiler and heat pumps explained.
Common questions
Is a heat pump cheaper to run than a gas boiler?
It depends on the heat pump's efficiency and the price gap between electricity and gas. At a SCOP of 3.5 and current prices the running costs are close, often within a small margin either way. A higher SCOP and a cheaper electricity tariff tip it in the heat pump's favour.
What is SCOP?
Seasonal Coefficient of Performance: the average units of heat a heat pump produces per unit of electricity across a year. A SCOP of 3.5 means 3.5kWh of heat for every 1kWh of electricity. Higher is better and cheaper to run.
How do I cut a heat pump's running cost?
Run it at a low flow temperature for a higher SCOP, insulate well so you need less heat, and use an electricity tariff with cheaper off-peak rates. The same heat demand on a better SCOP costs noticeably less.