Size a heat pump and compare running cost against a gas boiler.
A SCOP of 3.4 means each unit of electricity delivers 3.4 units of heat, which is what offsets the higher unit price of electricity. Whether running cost falls depends on the ratio between electricity and gas prices relative to the SCOP. Heat pumps must be sized to the actual heat loss rather than oversized, because oversizing forces cycling that reduces the achieved SCOP well below the rated figure.
Heat Pump Sizing
Electricity consumption = heat demand ÷ SCOP; capacity = design heat loss plus a small margin
Electricity consumption = heat demand ÷ SCOP; capacity = design heat loss plus a small margin A SCOP of 3.4 means each unit of electricity delivers 3.4 units of heat, which is what offsets the higher unit price of electricity. Whether running cost falls depends on the ratio between electricity and gas prices relative to the SCOP.
Heat pumps must be sized to the actual heat loss rather than oversized, because oversizing forces cycling that reduces the achieved SCOP well below the rated figure.
This calculator takes 5 inputs: Design heat loss, Seasonal coefficient of performance, Annual heat demand, Electricity price per kWh, Gas price per kWh. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.