Heat Pump vs Gas Boiler: Costs, Pros and Cons Compared (2026)

Heat pump vs gas boiler: quick verdict

If you want the headline: a gas boiler wins on upfront cost and speed; an air source heat pump wins on lifespan, carbon and (with the right tariff) long-term running cost. For most homes the two are far closer on running cost than the marketing suggests.

Here is the at-a-glance comparison for 2026. All figures are indicative UK ranges, not quotes.

Factor	Gas boiler	Air source heat pump
Typical install cost	£2,500–£4,500	£8,000–£15,000 (before grant)
Government grant	None	£7,500 (rising to £9,000 for oil/LPG homes from 21 July 2026)
Install time	24–48 hours	Typically 4–8 weeks from order
Efficiency	~90% (uses gas directly)	250–350% (SCOP ~3.5)
Typical lifespan	10–15 years	~20 years
Carbon emissions	Higher	~70% lower
Running cost (standard tariff)	Roughly the same	Roughly the same, can be slightly more
Running cost (heat-pump tariff)	n/a	~£200–£400/yr cheaper

How each system works

A gas boiler burns gas to heat water, which is pumped around your radiators and taps. It converts roughly 90% of the gas energy into useful heat — you can never get more out than you put in.

A heat pump moves heat rather than making it. It extracts warmth from the outside air (even in winter) and concentrates it using a refrigerant cycle, much like a fridge running in reverse.

That is why a heat pump can be more than 100% “efficient”. The key number is its COP (Coefficient of Performance): a COP of 3.5 means it delivers 3.5 units of heat for every 1 unit of electricity it uses. A gas boiler's equivalent is fixed at about 0.9.

Because electricity costs more per unit than gas, that 3.5× multiplier is exactly what closes the gap — the maths only works because the heat pump turns one expensive unit into three or four useful ones.

Upfront and installation cost compared

This is where the gap is widest. A like-for-like gas boiler replacement is one of the cheaper home jobs; a heat pump is a small project.

System	Typical 2026 install cost
Gas combi/system boiler	£2,500–£4,500 (avg ~£4,000)
Air source heat pump	£8,000–£15,000 before grant (avg ~£11,000–£12,500)
Ground source heat pump	~£18,000–£45,000 before grant (needs ground loops or boreholes)

A heat pump install often includes a hot-water cylinder, possible radiator upgrades and pipework, which is why it typically takes several weeks from order rather than a day or two. See our full breakdown of how much a new gas boiler costs in 2026 for the boiler side.

Running costs compared (2026) — the tariff-dependent maths

This is the part most guides oversimplify. On the 2026 Ofgem price cap, electricity runs at roughly 26p/kWh and gas at roughly 7p/kWh — electricity is about 3.5× the price of gas. (The exact cap rates change every quarter, so treat these as a 2026 snapshot.)

So the heat pump's COP almost exactly cancels out the price difference. At a COP of 3.5, a heat pump delivers useful heat at roughly the same effective cost per unit of heat as a 90%-efficient gas boiler. On a standard tariff that is near parity — a heat pump can even cost around £30–£40 a year more if its real-world efficiency dips.

The picture changes on a dedicated heat-pump electricity tariff, which gives cheap off-peak rates for heating. Examples available in 2026 (always check current rates on the provider's own page):

• Cosy Octopus — off-peak around 14–15p/kWh in three daily windows
• ScottishPower Heat Pump Saver — about 14p/kWh in a daily window (around 11am–4pm)
• Other suppliers, including British Gas, offer heat-pump or time-of-use options — compare current rates before switching

On a good heat-pump tariff, a heat pump typically saves £200–£400 a year versus gas. Other realistic comparisons cited by the Energy Saving Trust: replacing an old, inefficient gas boiler saves around £260/yr, while replacing electric storage heaters can save roughly £1,200/yr. Disconnecting from gas altogether also removes the gas standing charge (around £105/yr).

If you are staying on gas for now, our guides to what it costs to run gas central heating and ways to reduce your gas bill will help you trim the cost in the meantime.

The Boiler Upgrade Scheme grant (£7,500) and net cost

The Boiler Upgrade Scheme (BUS) is the single biggest reason heat pumps are now more affordable. It pays £7,500 off an air or ground source heat pump in England and Wales — with no income test.

From 21 July 2026 the grant rises to £9,000 for homes off the gas grid replacing an oil or LPG boiler (a temporary uplift, currently expected to run to the end of March 2027). Your MCS-certified installer applies and deducts the grant straight from your invoice, so you only pay the net amount. Confirm current eligibility on GOV.UK or with your installer before committing.

After the grant, a typical air source heat pump nets out at roughly £500–£7,500 — bringing the best cases close to a premium gas boiler install. Read our full guide to the £7,500 Boiler Upgrade Scheme grant for eligibility and how to claim.

15-year total cost of ownership

Headline savings ignore the awkward truth that a gas boiler will likely need replacing around year 10–15, plus annual servicing and (for many owners) breakdown cover. Bake those in and the comparison looks different.

Here is an illustrative 15-year run for a 3-bed semi, with the heat pump on a heat-pump tariff and after the £7,500 grant. Figures are rounded estimates for illustration only, not quotes — your own numbers depend on tariff, insulation and install price.

Cost element (15 years)	Gas boiler	Heat pump
Install (net of grant)	~£4,000	~£4,500
Year-10 replacement boiler	~£3,500	£0 (lasts ~20 yrs)
Annual servicing/cover (15 yrs)	~£3,000	~£2,000
Heating running cost (15 yrs)	~£8,000	~£8,000
Approx. 15-year total	~£18,500	~£14,500

On these assumptions the heat pump comes out around £4,000 cheaper over 15 years, and the Energy Saving Trust puts the gap at roughly £3,900 over 20 years. The result is highly sensitive to your tariff, insulation and how cheaply you got the install — change those and gas can still win.

Efficiency: COP, SCOP and what real homes achieve

COP is the efficiency at one moment; SCOP (Seasonal COP) is the average across a whole heating season, which is the number that matters for your bills.

• Air source heat pump design SCOP: around 3.5
• Ground source heat pump: around 4.0 (the ground is warmer and steadier than air in winter)
• Real-world UK seasonal performance: often 2.6–3.2

Even at the lower end, a heat pump produces around three times more heat energy than the electricity it consumes. A gas boiler is fixed near 0.9 — and if you want to squeeze more from your existing one, see making your existing boiler more efficient.

Cold-weather performance (do heat pumps work in winter?)

Yes. This is the most persistent myth. Heat pumps are standard heating across Scandinavia, where winters are far colder than the UK's.

Modern units using R290 refrigerant — available from a number of major manufacturers including Vaillant, Samsung and others — can maintain output at low outdoor temperatures, with many rated to keep working down to around −10°C or below (check the specific model's data sheet for its rated figures).

Efficiency does dip in the coldest weather (COP falls as the temperature gap widens), which is exactly when your SCOP matters. A correctly sized and designed system handles a British winter comfortably.

Will my radiators and home work with a heat pump?

A heat pump runs at a lower flow temperature (around 35–55°C) than a gas boiler (often 65–75°C). It heats your home gently and steadily rather than in short hot blasts.

That has three practical knock-ons:

• Insulation matters more. A draughty, poorly insulated home will struggle — loft and cavity insulation come first.
• Some radiators may need upsizing. Bigger surface area compensates for the lower flow temperature. Underfloor heating is ideal but not required.
• A hot-water cylinder is usually needed, so you need space for one (unlike a combi).

A good installer does a room-by-room heat-loss survey before quoting. If your home is hard to insulate, gas may remain the more sensible choice for now.

Carbon emissions and environment

A heat pump produces around 70% fewer carbon emissions than a gas boiler, and that gap widens every year as the UK grid uses more renewable electricity.

A gas boiler burns fossil fuel on site with no route to zero emissions. A heat pump's footprint keeps falling as the grid decarbonises — so today's figure is the worst it will ever be.

Lifespan and reliability (and what breaks)

A gas boiler typically lasts 10–15 years; a heat pump around 20 years. That longer life is a real part of the heat pump's cost case — see how long a gas boiler lasts for the boiler side.

What tends to fail differs. Gas boilers suffer pump failures, faulty diverter valves, PCB faults, leaks and pressure problems. Heat pumps have fewer wearing parts but can have issues with the fan, refrigerant circuit, sensors or the controls and weather compensation.

Pros and cons of each

Gas boiler — pros:

• Far cheaper to buy and fit
• Installed in 24–48 hours — ideal for emergencies
• Works with most existing radiators, no survey drama
• Strong, plumber-everywhere repair network

Gas boiler — cons:

• Burns fossil fuel; higher emissions
• Shorter lifespan; replacement due around year 10–15
• No grant available
• Exposed to long-term policy and gas-price risk

Heat pump — pros:

• 300%+ efficient; ~70% lower carbon
• £7,500 (or £9,000 for off-grid oil/LPG) grant available
• ~20-year lifespan
• Can cut running costs on the right tariff

Heat pump — cons:

• High upfront cost; weeks to install
• Needs decent insulation and possibly bigger radiators
• Needs space for an outdoor unit and cylinder
• Savings depend heavily on tariff choice

Who should get a heat pump vs stick with gas

A heat pump tends to make most sense if you have a reasonably well-insulated home, can sign up to a heat-pump tariff, have space for the outdoor unit and cylinder, and you are planning ahead rather than reacting to a breakdown. Off-grid oil and LPG homes have a strong case, with the £9,000 grant and expensive fuel to displace.

Gas may still make sense if your home is hard to insulate, you have no space for a cylinder, your budget is tight even after the grant, or — crucially — your boiler has just died and you cannot wait weeks for heat. This is general information; the right choice depends on your own home, so get a survey and your own quotes.

The gas boiler ban / 2035 timeline — does it force your hand?

There is no ban on using your existing gas boiler, and no requirement to rip one out. The policy direction is about new installations over time, not confiscating working systems.

You can still buy, fit and repair gas boilers today, and a boiler fitted now will see out its natural life. We cover the detail in is there a gas boiler ban in the UK? and the bigger picture in the future of gas boilers.

So the timeline is a reason to plan your next system thoughtfully — not a reason to panic-replace a boiler that is working fine.

What about repairs and cover for each?

Here is the angle most comparison pages skip: both systems break, and both cost money to keep running. Folding repair and cover costs into the decision gives you a far more honest picture than headline savings alone.

A gas boiler will need an annual service and, sooner or later, repairs — pumps, valves and PCBs are not cheap. Many owners take out boiler and central heating cover to cap that risk and get a priority engineer when something fails.

A heat pump usually comes with a longer manufacturer warranty (commonly around 5–7 years, sometimes more), but you still need to think about cover once that ends, plus annual checks to keep the warranty valid. Heat-pump repair cover is a newer market with fewer providers, so it is worth confirming availability and terms before you commit.

This article is general information, not financial or gas-safety advice. We compare a selected panel of providers, not the whole market, and may earn a commission if you buy through our links. Always have gas appliances checked and repaired by a Gas Safe registered engineer; in a gas emergency call 0800 111 999. Prices are indicative UK guides for 2026 — confirm current prices on the provider's own site.