SCOP
/ skop /
Also known as: seasonal coefficient of performance, heat pump efficiency
Definition
SCOP stands for seasonal coefficient of performance. It measures how efficient a heat pump is over a whole heating season, as the ratio of heat delivered to electricity used. A SCOP of 3.5, for example, means each unit of electricity produces on average 3.5 units of heat.
In practice
SCOP is higher than the efficiency of any boiler, which is why heat pumps can be cheaper to run than direct electric heating. It depends on the design flow temperature, the climate and how well the system is set up, so the lower the temperature the radiators or underfloor heating need to run at, the better the SCOP. Well-designed systems often achieve around 3 to 4, but results vary with the home.
When comparing quotes, ask for the SCOP the installer expects for your property and the flow temperature it assumes, not just the manufacturer headline figure. A related measure, COP, gives efficiency at a single moment rather than across the season.
Building Regulations
Figures vary by product, design and climate. Check the product data and your installer design estimate.
Full guide: Heat pumps for UK homesSee also