The only comparison that matters is cost per kWh of heat delivered. A heat pump at SCOP 3.5 on a standard tariff lands close to gas; on a heat-pump tariff it clearly beats gas. Efficiency — and therefore your bill — is mostly determined by flow temperature and commissioning.
Indicative comparison using your real bills — not a heat-loss survey or quotation.
Electricity at ~24.5p/kWh with SCOP 3.5 delivers heat at ~7.0p/kWh. Gas at ~6.3p/kWh in a real-world 85%-efficient boiler delivers heat at ~7.4p/kWh. That’s parity-to-better before smart tariffs — and a poorly commissioned pump at SCOP 2.5 (9.8p/kWh heat) loses to gas, which is why installation quality dominates everything else on this page.
A three-bed semi needing 12,000 kWh of heat: gas ≈ £890/yr (plus ~£110 gas standing charge). Heat pump at SCOP 3.5, standard tariff ≈ £840/yr. Same pump on a heat-pump tariff averaging ~18p ≈ £620/yr — and dropping the gas connection entirely removes the standing charge too. Well-insulated homes amplify the advantage because low flow temperatures push SCOP toward 4.
Dedicated heat-pump and time-of-use tariffs (cheap overnight/off-peak windows, sometimes type-of-use tracking) can cut effective electricity cost 25–40% versus standard rates. A pump gently pre-heating the home and cylinder in cheap windows shifts most consumption off peak. If you also have solar or a battery, self-supply pushes running costs lower still.
1) Lower the flow temperature — every 5°C down adds roughly 10% efficiency; many systems are commissioned lazily at 50°C+ when 40–45°C heats the home fine. 2) Enable weather compensation and tune the curve. 3) Run steady, not on/off — deep night setbacks force inefficient high-temperature recovery. 4) Balance radiators so every room delivers at low flow. 5) Legionella cycles weekly, not daily. These commissioning items are the difference between SCOP 2.8 and 3.8 in identical houses.
Facts checked 21 August 2026. We link to official sources and show when facts were last verified. If a scheme changes, we update the page.
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