Heat Pump vs Gas Boiler Running Costs (2026)
Whether a heat pump costs more or less to run than a gas boiler comes down to one ratio: your electricity price divided by your gas price, set against the heat pump's seasonal efficiency (SCOP). At typical 2026 standard tariffs the comparison is roughly a draw for a well-designed system; heat-pump tariffs tilt it toward the pump, poor design tilts it away, and against oil or LPG the pump commonly wins outright. Here's the arithmetic done honestly, so you can run it with your own numbers.
The arithmetic that decides it
A gas boiler at ~90% efficiency delivers 0.9 kWh of heat per kWh of gas; a heat pump at SCOP 3.5 delivers 3.5 kWh of heat per kWh of electricity. The break-even condition: the pump wins when electricity costs less than (SCOP ÷ 0.9) times gas — at SCOP 3.5, when electricity is under ~3.9× the gas price. Check your own tariff ratio against that multiple and you've answered the question for your house before anyone quotes anything.
Worked example on a 12,000 kWh-heat home: gas route uses ~13,300 kWh of gas; heat pump at SCOP 3.5 uses ~3,430 kWh of electricity. Price both at your actual unit rates (don't forget both standing charges — going all-electric can eventually remove the gas standing charge entirely) and the annual comparison falls out. At SCOP 3.0 the electricity climbs to 4,000 kWh; at SCOP 4.0 it drops to 3,000 — which previews the next section's point.
SCOP: the number design controls
SCOP isn't a property of the box; it's a property of the installation: flow temperatures (lower is better — 35–45°C designs achieve the good numbers; 55°C+ designs don't), emitter sizing (radiators large enough to heat the room at those low temperatures), controls set for steady running, and honest heat-loss calculation underneath it all. Well-designed UK installs achieve 3.3–4.0; skimped designs languish at 2.5–2.9 and lose the running-cost comparison they should have won.
This is why quotes shouldn't be compared on hardware price alone: the £1,500 saved on a design-light installation can cost £150–£250 every winter thereafter through the SCOP gap. Ask any quoting installer what SCOP the design targets and what flow temperature it's built around — MCS paperwork contains the answers, and installers proud of their designs volunteer them.
Tariffs: the number you control
Heat-pump electricity tariffs — cheap overnight windows, or discounted rates for verified heat pump homes — move the ratio decisively: shifting the comparison electricity price down 15–30% turns the standard-tariff draw into a clear pump win. The cylinder helps here: hot water charged in cheap windows is stored-cheap energy, and well-controlled homes shift some space-heating load the same way.
On the other fuels the contest shortens: LPG and oil cost more per kWh than mains gas, so the same SCOP arithmetic that draws against gas commonly wins against them outright — which is why off-grid homes are the heat pump's strongest financial audience, before the Boiler Upgrade Scheme grant touches the capital side. Electric-resistance heating (panel heaters, storage heaters) loses to a heat pump by definition: the pump delivers 3–4× the heat per kWh.
The whole-decision view
Running cost is one column of a longer ledger: capital (heat pump minus grant versus boiler — see our cost guides), lifespan (15–20+ years versus 10–15), servicing (comparable), carbon (pump wins decisively on any UK grid year, if that weighs for you), and comfort (well-designed pumps deliver steady warmth that most converts prefer, after unlearning boiler habits). Weight those columns your way; just fill them with your numbers rather than anyone's averages.
The honest bottom lines: mains-gas homes — a well-designed pump on a good tariff competes and often modestly wins; the decision can legitimately go either way and deserves real quotes. Oil/LPG homes — the pump comparison should be taken seriously as the default. Any home already renovating or insulating — get the heat pump quote first, because the fabric work is quietly doing the pump's design homework for it.
| Route | Fuel used | The maths |
|---|---|---|
| Gas boiler @ 90% | ~13,300 kWh gas | × your gas unit rate |
| Heat pump @ SCOP 3.0 | ~4,000 kWh elec | × your elec unit rate |
| Heat pump @ SCOP 3.5 | ~3,430 kWh elec | × your elec unit rate |
| Heat pump @ SCOP 4.0 | ~3,000 kWh elec | × your elec unit rate |
| Break-even rule | — | Pump wins if elec < (SCOP÷0.9) × gas price |
Timing the change well
Decisions like this have natural moments: replacement time (when something has failed anyway), renovation time (when floors are up and trades are on site), and pre-failure time (when the incumbent is old enough that acting on your schedule beats reacting on its). The expensive moment is mid-winter, choosing under pressure from a cold house. If your system is ageing, deciding now — even if executing later — is cheap insurance.
Frequently asked questions
Are heat pumps cheaper to run than gas in 2026?
At standard tariffs with a well-designed (SCOP 3.5+) system: roughly a draw, tilting pump-ward on heat-pump tariffs. Poor design loses the comparison; against oil or LPG the pump commonly wins outright. Run the ratio with your own rates.
What SCOP should a good UK installation achieve?
3.3–4.0 for well-designed systems built around low flow temperatures and properly sized emitters. Ask quoting installers their design SCOP and flow temperature — the MCS paperwork carries both, and the answers predict your bills.
Do heat pumps cost a fortune on the coldest days?
Efficiency dips in extreme cold and consumption rises — as gas usage does too. Seasonal (SCOP) figures already average this in; design sizing ensures the house holds temperature through design-condition cold snaps.
Is it worth switching tariff for a heat pump?
Usually yes — heat-pump and time-of-use tariffs shift the comparison price meaningfully, and cylinder-stored hot water exploits cheap windows naturally. Factor the tariff into the decision arithmetic, not as an afterthought.
If you'd rather hand this over
Plenty of readers reach this point, weigh the afternoon involved, and sensibly hand it to someone who does it weekly. No judgement — that's what the network exists for. Every engineer is Gas Safe registered (plus OFTEC for oil and MCS for heat pumps), insured and locally based; prices are agreed up front; and genuine no-heat emergencies are prioritised. Describe the symptoms you've identified here and you'll get an accurate price rather than a guess — informed customers reliably get better quotes.
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