Glossary
What is a Coefficient of Performance (COP)?
A measure of heat pump efficiency: units of heat output per unit of electricity input
COP measures how efficiently a heat pump converts electrical energy into heat energy. A COP of 3.0 means the pump delivers 3 kWh of heat for every 1 kWh of electricity used. UK heat pumps typically achieve a seasonal COP (SCOP) of 2.5-3.5. Higher COP means lower running costs.
Where it wins
- Simple standardised way to compare heat pump efficiency
- Helps estimate running costs before purchase
- Higher COP directly means lower energy bills
- Widely used benchmark across UK and EU
Where it struggles
- COP varies with outdoor temperature
- Lab-tested COP may differ from real-world performance
- Does not account for electricity used by pumps and fans
- Seasonal COP (SCOP) is more accurate but harder to find
How it works
01
Measure electricity consumed by the heat pump (kWh)
02
Measure heat delivered to your home (kWh)
03
Divide heat output by electricity input
04
Result is the COP (e.g. 3.0 = 300% efficiency)
Coefficient of Performance (COP): common questions
What is a Coefficient of Performance (COP)?
A measure of heat pump efficiency: units of heat output per unit of electricity input
How does a Coefficient of Performance (COP) work?
COP measures how efficiently a heat pump converts electrical energy into heat energy. A COP of 3.0 means the pump delivers 3 kWh of heat for every 1 kWh of electricity used. UK heat pumps typically achieve a seasonal COP (SCOP) of 2.5-3.5. Higher COP means lower running costs.
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