Before you begin
What this tool needs
Use annual fuel consumption or a BER advisory report to choose heat demand where possible.
Do not use a product laboratory COP as the expected seasonal COP.
Reading the answer
What your result means
A cheaper result is only protected if the installed system actually achieves the assumed SCOP.
Running cost excludes the capital cost, grants, finance and maintenance.
Boundaries
Assumptions and limitations
Working assumptions
- Kerosene contains 10.35 kWh per litre.
- Heat-pump useful-heat cost equals electricity rate divided by SCOP.
- Standing charges are excluded across fuels.
Where to be careful
- Emitter sizing, flow temperature, weather compensation and commissioning strongly affect real performance.
- A poorly insulated house may need insulation and draught-proofing work before a heat pump is suitable.
Common questions
Questions about this tool
What is SCOP?
SCOP is seasonal heat delivered divided by electricity used. A SCOP of 3.5 means roughly 3.5 kWh of heat per kWh of electricity over the season.
Can a heat pump be dearer than gas?
Yes. With a low SCOP and an expensive electricity tariff it can match or exceed efficient mains-gas heating.