Heat Pump Running Costs vs Gas Boiler: The Honest Numbers
Are heat pumps really cheaper to run than gas? The honest 2026 answer: roughly a wash on the standard tariff — but £200–£400 a year cheaper on a heat-pump tariff. Here’s what actually decides it.
The honest short answer
On a standard tariff, a heat pump costs roughly the same to run as a gas boiler; on a dedicated heat-pump tariff, it’s clearly cheaper. For a typical 3-bed semi (12,000 kWh heat/year) at the 2026 price cap, a gas boiler costs ~£780–£960/year, and a well-installed heat pump at SCOP 3.5 costs ~£900 — marginally cheaper, but genuinely close. At a lower SCOP of 3.0 it’s ~£1,050, slightly more than gas. That’s why you see conflicting claims online: on the standard cap, it’s roughly a wash, and your SCOP decides it.
The game-changer is the tariff: on a dedicated heat-pump tariff (like Octopus Cosy or Intelligent Octopus, ~11–15p off-peak), a heat pump costs £350–£640/year — saving £200–£400 vs gas. So three things decide your running cost: SCOP (efficiency), your tariff, and your insulation. And if you’re replacing oil, LPG or electric heating, a heat pump saves far more (up to ~£2,000/year for electric). We’ll be straight with you throughout — no overselling. Full numbers below. (For the whole heat-pump decision — install cost, grant, disruption — see our are heat pumps worth it? guide.)
What this guide covers
The real running-cost numbers vs gas
| Heating (3-bed semi, 12,000 kWh/yr) | Annual running cost |
|---|---|
| Gas boiler (modern, ~90%) | ~£780–£960 |
| Heat pump, SCOP 3.0, standard tariff | ~£1,050 (slightly more) |
| Heat pump, SCOP 3.5, standard tariff | ~£900 (marginally less) |
| Heat pump on a heat-pump tariff | ~£350–£640 (£200–£400 less) |
| Electric heating (for comparison) | ~£3,000+ (HP saves ~£2,000) |
Let’s be straight, because a lot of sites aren’t. Using the July 2026 Ofgem price cap (electricity 26.11p/kWh, gas 7.33p/kWh) for a typical 3-bed semi: a gas boiler costs roughly £780–£960 a year to run, based on Energy Saving Trust and Ofgem figures. A well-installed heat pump at SCOP 3.5 costs about £900 — so marginally cheaper than gas, but close. If the heat pump only manages SCOP 3.0, it costs about £1,050 — slightly more than gas. So on the standard price cap, it’s essentially a wash, tipping one way or the other depending on efficiency. The running-cost maths is simple: annual heat demand ÷ SCOP × electricity price (so 12,000 ÷ 3.0 × 26.11p ≈ £1,044). The two levers that change this dramatically — SCOP and tariff — are next.
SCOP: the number that decides everything
Your heat pump’s SCOP is the single biggest factor in its running cost
SCOP (Seasonal Coefficient of Performance) measures how many units of heat the pump delivers per unit of electricity, across a whole heating season. A SCOP of 3.0 = 3kWh of heat per 1kWh of electricity (300% efficient); 3.5 = 3.5kWh, and so on. It directly sets your running cost: higher SCOP = less electricity for the same heat = cheaper to run.
At 2026 prices, a heat pump needs a SCOP of about 3.2 just to match a gas boiler on a standard tariff. So SCOP 3.5+ saves money; SCOP 2.8–3.0 costs the same or more than gas. UK MCS installations average around 2.8–3.5 — well-designed systems in well-insulated homes hit 3.2–3.8, while poorly-designed systems in draughty homes manage only 2.0–2.5. This is why installation quality and system design matter more than the brand: the same heat pump can be cheap or expensive to run depending on how well it’s specified and set up. When comparing quotes, ask for the estimated SCOP for your specific installation — and choose an experienced MCS-certified installer who designs it properly (see our best heat pumps guide for high-SCOP models, and Kensa ground-source for the highest SCOPs of all).
The heat-pump tariff game-changer
Here’s what turns a heat pump from “about the same as gas” into “clearly cheaper”: a dedicated heat-pump electricity tariff. Tariffs like Octopus Cosy and Intelligent Octopus offer cheap off-peak rates of around 11–15p/kWh — versus ~26p on the standard cap — specifically timed for when a heat pump runs hardest. On one of these, a heat pump for our typical home costs around £350–£640 a year, saving £200–£400 versus gas (roughly 18%+ cheaper). The heat pump is set to do most of its work during the cheap-rate windows (helped by the home’s thermal mass and, ideally, a buffer or the hot water cylinder). This is the single most effective lever on running cost — and it’s why any honest running-cost comparison has to specify the tariff. On the standard cap, gas and heat pumps are close; on a heat-pump tariff, the heat pump wins comfortably. If you’re going to run a heat pump, a heat-pump tariff is essential to getting the best from it — and pairing with a battery to store cheap off-peak power extends the benefit further.
The honest verdict
We’ll give you the straight version that many sites won’t: on a standard electricity tariff, a well-installed heat pump costs about the same to run as a modern gas boiler — sometimes marginally less, sometimes marginally more, depending on its SCOP. Anyone claiming heat pumps are always dramatically cheaper to run than gas is overselling. But — and it’s a big but — with the two things that matter (a good SCOP of 3.5+ and a dedicated heat-pump tariff), a heat pump becomes genuinely cheaper, by £200–£400 a year. And there are extra financial pluses: you can drop the gas standing charge entirely (~£120–£180/year saved), the heat pump lasts longer, and you avoid a future gas-boiler replacement. Add ~70% lower carbon emissions, and the case is sound — provided you go in with realistic expectations and set it up right. For the full financial picture including the install cost and the £7,500 grant, see our are heat pumps worth it? guide.
When heat pumps save the most
Running-cost savings are biggest when you’re replacing a more expensive fuel than mains gas:
- Replacing electric heating (storage/panel heaters): the biggest win by far — a heat pump can save around £2,000 a year for a typical home, because you’re going from ~26p/kWh direct electric to an effective ~8–9p/kWh via the heat pump.
- Replacing oil: saves roughly £100–£200+ a year (more with an old, inefficient oil boiler) — a clear win for off-grid homes.
- Replacing LPG: also a strong saving, as LPG is expensive.
- Replacing mains gas: the closest comparison — a wash on standard tariff, £200–£400 cheaper on a heat-pump tariff.
So if you’re off the gas grid (oil, LPG or electric), a heat pump is very likely cheaper to run right now — often substantially. If you’re on mains gas, the running-cost case depends on getting the SCOP and tariff right. Ground-source heat pumps like Kensa have the lowest running costs of all, thanks to their higher efficiency.
How to cut your heat pump running costs
To get your running costs to the low end, these are the levers, in order of impact:
- Get on a heat-pump tariff (Cosy, Intelligent Octopus) — the biggest single saving.
- Ensure a high SCOP — good design, correct sizing, weather compensation, and running “low and slow” at lower flow temperatures.
- Improve insulation — loft, cavity walls, draught-proofing reduce heat demand so the pump works less (especially in older homes).
- Pair with solar panels — run the pump partly on your own free electricity, especially spring/autumn.
- Add a battery — store cheap off-peak power to run the pump at peak times.
- Run steadily — heat pumps are most efficient holding a constant temperature, not big on/off swings.
Combined, a heat-pump tariff plus a well-designed high-SCOP system is what separates a heat pump that costs about the same as gas from one that’s clearly, satisfyingly cheaper.
Frequently asked questions
What are heat pump running costs vs a gas boiler?
For a 3-bed semi in 2026: gas boiler ~£780–£960/yr; heat pump at SCOP 3.5 ~£900 (marginally less); at SCOP 3.0 ~£1,050 (slightly more). So on the standard cap it’s roughly a wash. But on a heat-pump tariff (~11–15p off-peak), the heat pump costs ~£350–£640 — saving £200–£400/yr. SCOP and tariff decide it.
Are heat pumps cheaper to run than gas?
Honestly: on a standard tariff, roughly the same (it depends on SCOP). Clearly cheaper in three cases: on a dedicated heat-pump tariff (£200–£400/yr less), at a high SCOP of 3.5+, or replacing oil/LPG/electric (up to ~£2,000/yr for electric). Anyone claiming heat pumps are always far cheaper than gas is overselling — but with the right setup, they are cheaper.
What is SCOP and why does it matter?
SCOP (Seasonal Coefficient of Performance) = units of heat per unit of electricity, over a season. SCOP 3.0 = 300% efficient. It decides your running cost: you need ~3.2 to match gas, 3.5+ to save. UK installs average 2.8–3.5; good design in an insulated home hits 3.2–3.8. Installation quality matters more than brand — ask for your estimated SCOP. See best heat pumps.
How do I reduce my heat pump running costs?
Biggest lever: a heat-pump tariff (Intelligent Octopus/Cosy, ~11–15p). Then: a high SCOP (good design, weather compensation, low-and-slow running), better insulation, pairing with solar and a battery, and running at a steady temperature. A heat-pump tariff + high-SCOP system is what makes it clearly cheaper than gas.
When does a heat pump save the most on running costs?
When replacing expensive fuels: electric heating (~£2,000/yr saved — the biggest win), oil (£100–£200+), and LPG. Versus mains gas it’s a wash on standard tariff, £200–£400 cheaper on a heat-pump tariff. Off the gas grid, a heat pump is very likely cheaper now. Ground-source pumps have the lowest running costs of all.
Do you still pay a gas standing charge with a heat pump?
No — if a heat pump fully replaces your gas heating and you disconnect from gas, you drop the gas standing charge entirely, saving ~£120–£180/year. That’s a real running-cost benefit on top of the fuel savings. (If you keep gas for cooking, you’d still pay it.) Combined with lower emissions and a longer lifespan, it strengthens the running-cost case.
The honest bottom line
We’ll give it to you straight: on a standard electricity tariff, a heat pump costs about the same to run as a modern gas boiler — the exact outcome hinges on your system’s SCOP. That’s the honest reality, and any site promising huge guaranteed savings over gas on a like-for-like tariff is overselling. But get the two things that matter right — a good SCOP (3.5+) and a dedicated heat-pump tariff — and a heat pump becomes genuinely cheaper, by £200–£400 a year, plus you drop the gas standing charge and cut carbon by ~70%. And if you’re replacing oil, LPG or electric heating, a heat pump is a clear running-cost winner today, saving up to ~£2,000 a year.
So the running-cost question really comes down to your home, your system’s efficiency, and your tariff — which is exactly what a proper survey assesses. A couple of free, no-obligation home surveys from MCS-certified installers will give you a realistic estimated SCOP and running cost for your property, so you can see the honest numbers rather than a marketing promise. And for the complete financial picture — install cost, the £7,500 grant and payback — see our are heat pumps worth it? guide.
Important
Going Solar UK is an introduction service, not an installer. This guide gives general 2026 UK information on heat pump running costs for research: actual costs vary by property, heat demand, system efficiency (SCOP), insulation, electricity tariff and energy prices, all of which change over time – the figures here (based on the July 2026 Ofgem price cap and typical assumptions) are estimates, not guarantees. Energy prices and tariffs change frequently. Always get a professional survey and a system-specific SCOP and running-cost estimate from MCS-certified installers before deciding.
We may receive a commission when we introduce you to an installer, at no cost to you. Any contract for work is directly between you and the installer.