Heat Pump Key Figures and Sizing - Summary
To compare heat pumps and choose the right size, important key figures exist.
COP – Coefficient of Performance
Definition: The ratio of generated heat output to electrical power input – measured under standard conditions.
Formula: COP = Heat Output (kW) / Electrical Power (kW)
| COP | Meaning |
|---|---|
| 3.0 | For 1 kW electricity you get 3 kW heat |
| 4.0 | For 1 kW electricity you get 4 kW heat |
| 5.0 | For 1 kW electricity you get 5 kW heat |
Guideline: A COP above 4 is good, above 5 is very good.
SPF – Seasonal Performance Factor (JAZ)
The annual average efficiency under real operating conditions. More meaningful than COP as it includes all losses over the heating season.
Sizing Rule of Thumb
Heat pump power ≈ Heating load × 1.0 to 1.2
For a house with 10 kW heating load: 10-12 kW heat pump