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heatpumpsaver .co.uk · MCS data

Tool · Updated quarterly

Heat pump cost calculator

Six inputs. Real install costs, real running costs, real payback period. Updates live as you change values. Nothing is sent anywhere — calculation is in your browser.

Cost calculator

Get your personalised numbers

Install cost, running cost vs your current fuel, and payback period — based on your home, not generic averages. Methodology published below.

How we calculate

Install cost

Drawn from aggregated MCS installation records (2024 calendar year). We use a low–high range to reflect regional variation, complexity (radiator upgrades, pipework, cylinder replacements), and installer pricing differences. Mid-point is shown for payback calculations.

Heat demand

Per-property heat demand baselines come from Energy Saving Trust modelling, adjusted by an insulation multiplier:

  • Good insulation: 85% of base demand
  • Average insulation: 100% of base demand
  • Poor insulation: 125% of base demand

Running cost

Calculated as useful heat × cost per kWh of heat delivered. Cost per kWh of heat depends on fuel efficiency and tariff:

  • Heat pump on Octopus Cosy: £0.06–£0.08 per kWh useful heat
  • Heat pump on standard variable: £0.065–£0.085 per kWh useful heat
  • Gas boiler: £0.085 per kWh useful heat
  • Oil boiler: £0.105 per kWh useful heat
  • LPG boiler: £0.155 per kWh useful heat
  • Direct electric: £0.27 per kWh useful heat

These figures are updated each time Ofgem revises the price cap (quarterly). Last refresh: Q4 2024.

Payback period

Calculated as net install cost (after grant) ÷ annual running cost saving. Where saving is zero or negative, payback is "N/A" — the heat pump is run on running-cost grounds alone, not financial payback.

What we don't model (yet)

  • Annual maintenance cost differences (typically minor: £80–£150/yr both for HPs and gas boilers)
  • Equipment replacement at end of life (HP unit ~15–20 yrs; boiler ~10–15 yrs)
  • Carbon emissions / future carbon pricing
  • EPC rating uplift effect on property value

These each have modest effect on totals but compound over time. Conservatively, modelling them tends to improve the heat pump case further — particularly versus oil and LPG.

Sources

  • MCS installation cost data: MCS Installation Database, 2024.
  • Heat demand baselines: Energy Saving Trust, "Heat Pump Performance Study", 2024.
  • Energy prices: Ofgem default tariff cap, Q4 2024.
  • Octopus Cosy rates: Octopus Energy public tariff page, accessed quarterly.
  • SCOP figures: BEIS heat pump efficiency dataset, 2023.

Calculator — frequently asked

How accurate is this calculator?

It uses 2024 MCS install cost ranges, Q4 2024 Ofgem cap pricing, and EST heat demand baselines. Accurate to within roughly ±15% for typical UK homes. For non-standard properties (very large, very small, off-grid, listed buildings) seek a quote — calculator outputs become wider.

Why does the calculator show running cost — not just install cost?

Heat pump decisions are about total cost of ownership over 10–15 years, not just the install. A cheap install with high running costs costs more in total than a slightly higher install with a heat-pump tariff. We model both so you see the real picture.

What is "useful heat" in your methodology?

Useful heat is the energy delivered into your home as warmth — not the energy your boiler or heat pump consumes. A gas boiler uses about 1.15 kWh of gas to deliver 1 kWh of useful heat (87% efficient); a heat pump uses about 0.30 kWh of electricity to deliver the same 1 kWh (SCOP ~3.3). We compare on the basis of useful heat to make the maths comparable.

Numbers look good? Find local MCS installers.

Once you've modelled the cost picture, see up to three MCS-certified installers covering your postcode area. No paid placements.

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