Glossary · Heating, cooling & ventilation
Seasonal COP
Also called: SCOP · seasonal coefficient of performance
A heat pump's average heat output per unit of electricity over a whole heating season, including defrost and backup heat, instead of at one temperature.
What it means
A single COP describes one moment, such as 3.0 at 8°C (46°F), but efficiency falls as it gets colder and drops further when backup heat runs. Seasonal COP averages all of that over a location's winter, so it's the number that drives your heating bill. Dividing a heat pump's HSPF2 by 3.412 gives a rough seasonal COP for the rating's test climate.
Why it matters in an audit
Energy cost calculators use seasonal COP to compare a heat pump with gas, oil or baseboards, so a realistic value for your climate matters more than the best-case rating.
Typical numbers
Reference values with their sources. Your energy advisor’s report gives the figure for your own house.
| What | Value | Source |
|---|---|---|
| From HSPF2 | Seasonal COP ≈ HSPF2 ÷ 3.412 (for example, HSPF2 8.5 ≈ 2.5) | Arithmetic (1 watt-hour = 3.412 Btu, EIA) |
| Electric baseboards and furnaces | 1.0: one unit of heat for each unit of electricity | Definition |