Glossary
What Is a Coefficient of Performance (COP)? Plain-English Guide (2026)
Definition: A measure of heat pump efficiency: units of heat output per unit of electricity input
Coefficient of Performance (COP) Explained
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.
How Does a Coefficient of Performance (COP) Work?
- Measure electricity consumed by the heat pump (kWh)
- Measure heat delivered to your home (kWh)
- Divide heat output by electricity input
- Result is the COP (e.g. 3.0 = 300% efficiency)
Pros and Cons of a Coefficient of Performance (COP)
| Pros | Cons |
|---|---|
| Simple standardised way to compare heat pump efficiency | COP varies with outdoor temperature |
| Helps estimate running costs before purchase | Lab-tested COP may differ from real-world performance |
| Higher COP directly means lower energy bills | Does not account for electricity used by pumps and fans |
| Widely used benchmark across UK and EU | Seasonal COP (SCOP) is more accurate but harder to find |
Frequently Asked 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.
Why is a Coefficient of Performance (COP) important for homeowners?
Understanding coefficient of performance (cop) helps you make informed decisions about energy improvements to your home and may affect the grants, savings and payback periods available to you.
Is a Coefficient of Performance (COP) relevant to home energy improvements?
Yes — coefficient of performance (cop) is a key concept in home energy improvements. It may affect system sizing, efficiency and eligibility for government grants and incentives.
Where can I learn more about coefficient of performance (cop)?
You can find more information on renewable energy terminology and policy by searching online or consulting with a qualified installer in your area.