Boiler vs Heat Pump Calculator
Enter your home size, current heating system and heat pump details to compare estimated annual running costs, potential savings and payback period.
Quick Start
Tip: All figures are estimates based on heat demand models. Actual running costs depend on your heating habits, system sizing, climate and tariff structure. Use this calculator to get a directional comparison, not a precise quote.
Project
Your Home
Current Heating System
Heat Pump
Common questions
Is a heat pump cheaper to run than a gas boiler? +
It depends on your gas and electricity prices and the heat pump's seasonal COP. In many countries, electricity costs 3–5 times more per kWh than gas. A heat pump needs a COP above that ratio to be cheaper. The break-even COP equals your electricity price divided by your gas price — if electricity is $0.28 and gas is $0.07, you need a COP above 4.0 to beat gas on running costs.
What COP do I need to beat my current system? +
The break-even COP = (electricity price ÷ fuel price) × current system efficiency. For example: electricity $0.28, gas $0.07, boiler efficiency 90% → break-even COP = (0.28 ÷ 0.07) × 0.90 = 3.6. The calculator shows your break-even COP in the results.
How long does a heat pump take to pay back? +
Simple payback = installation cost ÷ annual saving. A $12,000 installation saving $600/year pays back in 20 years without grants. Many governments offer subsidies that significantly reduce upfront costs. Enter your installation cost above to see your estimated payback period.
Does insulation affect heat pump performance? +
Yes, significantly. Better insulation reduces annual heat demand, which directly reduces both systems' running costs. Improving insulation before installing a heat pump can also allow a smaller, less expensive unit to be specified. For poorly insulated homes, addressing the building fabric first often gives a better return than switching heating systems.
Boiler vs heat pump — understanding the comparison
Is a heat pump cheaper to run than a boiler?
The answer depends on three numbers: your electricity price, your fuel price, and the heat pump's seasonal COP. A heat pump does not generate heat — it moves it. For every unit of electricity consumed, it delivers 2.5–5 units of heat. Whether that makes it cheaper than a gas boiler depends entirely on the ratio of electricity to gas prices in your area.
The break-even COP formula
Break-even COP = (electricity price ÷ fuel price) × boiler efficiency. If your electricity costs $0.28/kWh, gas costs $0.07/kWh and your boiler runs at 90% efficiency, the break-even COP is (0.28 ÷ 0.07) × 0.90 = 3.6. Any heat pump achieving SCOP above 3.6 will cost less to run than your gas boiler at those prices. Modern air source heat pumps in average climates typically achieve SCOP 3.0–4.0, and ground source systems 3.5–5.0.
Why insulation matters more than the system
Annual heating cost = heat demand × energy cost per unit of heat delivered. A heat pump in a poorly insulated home may still cost more than a boiler in a well-insulated one. Before comparing systems, it is worth estimating your heat demand. The insulation level input in this calculator uses typical kWh/m²/year values — adjust it to reflect your actual home if you have an energy performance certificate (EPC or equivalent).
What this calculator does not include
This comparison covers space heating running costs only. It does not include hot water (which adds roughly 20–30% to a heat pump's annual electricity use), standing charges, maintenance costs or the cost of radiator or underfloor heating upgrades that may be needed when switching to a heat pump. For a full picture, use the results here as a starting point and get quotes from installers.
For a detailed ROI analysis including payback curves, see the Heat Pump ROI Calculator. To see how insulation improvements affect your heating bill, try the Insulation Savings Calculator.