SCOP: how to compare heat pumps on the data sheet
In short
SCOP is a heat pump's average performance over the whole heating season. To compare two units, read it at the same water temperature (35 °C for underfloor heating, 55 °C for radiators) and in the same reference climate.
Author: Climai Group technical teamTechnical review: Climai GroupUpdated:
What is the difference between COP and SCOP?
- COP: how much heat the unit gives per unit of electricity at one specific operating point (one outdoor temperature and one water temperature).
- SCOP: the average performance over the whole heating season. Regulation 813/2013 defines it as the ratio between the reference annual heating demand and annual energy consumption.
For comparing units, SCOP is what counts.
Why does water temperature matter?
A heat pump performs better the cooler the water it has to produce. That is why the regulation distinguishes two applications:
| Application | Water outlet temperature | Typical emitter |
|---|---|---|
| Low temperature | 35 °C | Underfloor heating |
| Medium temperature | 55 °C | Radiators |
The same unit has a higher SCOP at 35 °C than at 55 °C. If you compare two offers, read both at the same temperature, the one your home will need.
In which climate is it measured?
The data sheet declares performance in average reference climate conditions: those of Strasbourg, with a design temperature of –10 °C. Ibiza is much milder, so the figure is for comparing units with each other, not for knowing exactly what you will spend. We explain it in do heat pumps work in winter in Ibiza?.
What is seasonal efficiency (ηs)?
It is the same performance expressed as a percentage of primary energy. The regulation calculates it by dividing SCOP by a conversion coefficient and applying corrections, for example for temperature controls.
Since 26 September 2017, Regulation 813/2013 requires:
| Unit | Minimum seasonal efficiency |
|---|---|
| Heat pump (except low-temperature ones) | 110 % |
| Low-temperature heat pump | 125 % |
A low-temperature heat pump is, according to the regulation, one that cannot supply water at 52 °C with –7 °C outside. It suits underfloor heating, but not standard radiators.
How do you compare two data sheets?
- Same application: SCOP at 35 °C if you have underfloor heating; at 55 °C if you have radiators.
- Same reference climate on both data sheets.
- Similar output: comparing a 6 kW unit with a 12 kW one makes no sense.
- Refrigerant: R290 or R32. See R290: the natural refrigerant.
- Noise of the outdoor unit, if it is near bedrooms or neighbours.
- Operating range and maximum water temperature, if you have radiators.
Frequently asked questions
Which is better, a high SCOP or a high COP?
What is a good SCOP?
Why does the data sheet give two different values?
Is the data sheet SCOP what I will get at home?
What is seasonal efficiency (ηs)?
What minimums does the regulation require?
Sources
- Regulation (EU) No 813/2013, ecodesign requirements for space heaters (OJ L 239, 6.9.2013) · Official Journal of the European Union ·
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