COP, SCOP & SEER: How to Compare Heat Pump Ratings (2026)
Updated: 2026-10-01 · ~2 min read
The three numbers and what each one means
| Metric | What it measures | Typical range (ASHP, temperate climate) |
|---|---|---|
| COP | instantaneous: heat delivered ÷ electricity at one operating point (standard test condition, e.g. 7 °C outdoor / 35–40 °C water) | ~3–5 depending on model and test point |
| SCOP | seasonal: weighted average COP over a full heating season (standard climate profile, e.g. EU "A" temperate zone) | ~3.0–4.5 for air-source; the number to compare when buying |
| SEER | seasonal efficiency of cooling mode (same logic as SCOP but for dehumidification/cooling) | relevant only if you use the unit for summer cooling |
The comparison rules that prevent buying errors
- Compare SCOP to SCOP, not COP to COP. A marketing COP of 5.0 at a mild test point tells you almost nothing about winter; two models with identical headline COP can have very different seasonal performance.
- Match the climate zone. SCOP is calculated on a standard outdoor temperature profile; if your area is colder than the test profile (or milder), real seasonal efficiency shifts accordingly. Check which climate class the declared value refers to.
- Water temperature matters. Same model, 55 °C vs. 40 °C setpoint → different COP and SCOP. If your install needs high water temps (older radiators), the effective efficiency is lower than the brochure figure taken at low temperatures.
- COP is not a warranty of energy use. Real seasonal electricity = seasonal heat demand ÷ your real seasonal efficiency; insulation dominates (a well-insulated house at SCOP 3.5 beats a poor one at SCOP 4.2).
How to use this in a purchase decision
- Take the SCOP for your climate class and water temperature from the rating label/certificate, not the brochure headline.
- Compute expected seasonal electricity: e.g. 12,000 kWh heat/season ÷ SCOP 3.5 ≈ 3,400 kWh — then multiply by your local tariff (see seasonal cost guide).
- If you need cooling too, check SEER separately — a unit optimized for high COP heat delivery isn't automatically the best cooler.
The one-line summary
COP = snapshot, SCOP = season, SEER = cooling season. Buy on SCOP in your climate class at your real water temperature — and verify with an energy audit of the building first, because insulation is half the investment.
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Sources
- EU labeling standards for heat pumps (EN 14511 / EPREL methodology — SCOP, seasonal climate profiles); as of October 1, 2026.
- SEER rating basis (AHRI 210/240-style seasonal cooling ratings); as of October 1, 2026.