Quick estimate mode — for old fuel comparison, payback period and year-by-year projection: Full calculator →

Quick Heat Pump Calculator

Enter your home size and heat pump details to get your annual running cost and saving vs gas or direct electric heating.

Your Home & Heat Pump

Total heated floor area of your home.
Typical annual heat demand per m² floor area.
Check your energy bill for the unit rate.

Result

Annual cost
–
/year
Annual saving
–
vs old heating

Estimate based on floor area and insulation level. Actual results depend on heating habits, climate and system settings.

Need payback period, custom fuel price and year-by-year projection?
Full calculator covers exact SCOP, standing charges, old boiler efficiency and 20-year cumulative saving.
Full Calculator →
How to calculate heat pump running cost

The formula

Annual electricity use (kWh) = heat demand (kWh) ÷ SCOP. Annual cost = electricity use × electricity price (per kWh).

What is SCOP?

SCOP (Seasonal Coefficient of Performance) is the average efficiency of your heat pump across a full heating season. A SCOP of 3.5 means 3.5 kWh of heat delivered for every 1 kWh of electricity consumed. Air source heat pumps typically achieve SCOP 2.5–4.5; ground source 3.5–5.0.

Heat pump vs gas boiler

At UK electricity prices (~£0.24/kWh) and gas prices (~£0.068/kWh), a heat pump with SCOP 3.5 delivers heat at £0.069/kWh — almost identical to gas. But as gas prices rise and grid electricity gets greener, the heat pump advantage grows every year.

Pro tip: Insulating before installing a heat pump reduces your heat demand and cuts running costs further — and may let you specify a smaller, cheaper unit.
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