Reading an EU energy label for heat pumps

What the label tells you

Every heat pump sold legally in the EU carries a printed energy label. For space heaters the layout is fixed by Regulation 811/2013 and shows four numbers that matter for buyers:

• Energy class (A+++ to D, or for newer products A to G after the

2021 rescale) — overall headline

• ηs — Seasonal Space Heating Energy Efficiency, in percent
• Heat output in kW
• Sound power level, in dB

The label is fed from the supplier's EPREL registration. It is the marketing face of the same numbers we publish on every model page.

ηs is not SCOP — but they are related

ηs is the percentage you see on the label. SCOP is the seasonal-average efficiency you see in spec sheets. The relationship under EN 14825:

ηs ≈ (SCOP / CC − 0.03) × 100

where CC = 2.5 is the EU primary-energy conversion coefficient. A heat pump with SCOP 4.5 therefore carries ηs ≈ 177% which maps to A++ on the new scale. Going the other way:

SCOP ≈ (ηs / 100 + 0.03) × 2.5

Climate zones on the label

The label often shows a small Europe map split into three zones: Warmer (Athens reference), Average (Strasbourg) and Colder (Helsinki). Each zone has its own ηs because COP changes with outdoor temperature. When two products quote different ηs values, make sure you are comparing the same zone.

Two temperatures, two labels

For air-to-water heat pumps the label shows two ηs values: one for low-temperature application (35 °C supply, typical underfloor) and one for medium-temperature application (55 °C, typical radiators). The same compressor performs very differently between the two — pay attention to which one matches your home.

Sound power vs sound pressure

The label number is sound power (LWA, the source's intrinsic loudness). What you hear at three metres on a quiet evening is sound pressure (LpA). Conversion under typical free-field conditions subtracts roughly 8 dB at 3 m, more at greater distance. A unit labelled at 54 dB sound power is around 46 dB three metres away — about the level of a refrigerator.

What the label does NOT tell you

• Refrigerant code and GWP — only on the data sheet
• Performance below the design temperature — ηs is an integral,

not a guarantee for the coldest day

• Real-world COP — labels are based on standardised lab tests
• Defrost behaviour and inverter modulation — also data sheet

For our catalog we publish ηs, derive SCOP, and link to the original EPREL registration so you can verify both. See{" "} methodology for the formulas in full.