Heat Pumps vs Boilers in 2026: Real Numbers from UK Homes
The short version of heat pump vs boiler UK in 2026 is this: a new A-rated gas combi still costs less to install than an air-source heat pump by roughly £4,000 to £8,000, but a correctly sized heat pump in a well-insulated semi now runs at parity with — and in many homes cheaper than — a modern gas combi on the standard unit-rate cap. The crossover point that took mortgage-cost analysis until 2024 to admit has now hardened on the bills page. This guide uses 2026 install quotes, the £7,500 Boiler Upgrade Scheme as it actually pays out, and SCOP figures from MCS-certified installers — not manufacturer brochures — to give you the honest comparison.
What has actually changed since 2024
Three things. First, the Boiler Upgrade Scheme grant for an air-source heat pump in England and Wales is still £7,500, and the application is now routinely handled by the installer rather than the homeowner, which has cut the average install lead time from sixteen weeks to under ten. Second, the gas-to-electricity unit-rate ratio under the price cap has narrowed: in 2022 electricity cost about four times as much as gas per kWh, in 2026 it sits closer to 3.2x on the default tariff and as low as 2.4x on the best dedicated heat-pump tariffs. Third, real-world SCOP — the Seasonal Coefficient of Performance, the number that tells you how many kWh of heat you get out for every kWh of electricity in — has crept up. Decent 2026 installs in averagely insulated UK homes are now delivering SCOPs of 3.2 to 3.8 across a full heating season. The maths have shifted underneath the old advice.
Install cost in 2026: what each one actually costs
A like-for-like A-rated gas combi swap — same location, same flue, no system upgrade — sits at £2,800 to £4,500 in 2026 for a Worcester Bosch, Vaillant, Ideal or Viessmann unit on a three-bed semi, fitted by a Gas Safe registered engineer. Add £400 to £900 if the boiler is moving to a new position, the gas supply needs upsizing, or a power flush is included.
A regular boiler-to-system or combi-to-system conversion — needed if you are going from a cylinder setup to a combi or vice versa — adds £600 to £1,500 of pipework on top, plus the cost of the cylinder if you are keeping hot-water storage. A typical full system replacement on an older four-bed lands at £4,500 to £6,500 once you have included thermostatic radiator valves, a smart thermostat and a magnetic filter.
An air-source heat pump install on the same semi comes in at £10,500 to £14,500 before the grant in 2026, depending on the emitter work needed. After the £7,500 Boiler Upgrade Scheme grant the homeowner cash outlay is typically £3,000 to £7,000 — sometimes below the cost of a like-for-like gas system replacement, sometimes still above. The variable is the emitters: if your radiators are already oversized or you have space for an unvented cylinder, you are at the low end. If three radiators need swapping for larger panels or you need a buffer tank, you are at the high end. Ground-source remains a £19,000 to £30,000 install and only makes sense for properties with the land for a slinky loop or borehole.
Running cost: what each one costs to fire up next winter
Take a three-bed semi using around 12,000 kWh of heat per year — a slightly-better-than-average UK figure. With a gas combi running at 90% efficiency, that is 13,300 kWh of gas in, at about 6.5p per kWh under the prevailing 2026 cap, which works out to roughly £865 in gas units. Add the daily gas standing charge (around £115 a year in 2026) and a typical year on the gas combi comes to about £980, before annual service.
The same 12,000 kWh of heat from a heat pump running at a SCOP of 3.5 needs 3,430 kWh of electricity. On the standard electricity cap at about 24p per kWh that is £825 in electricity units. On a dedicated heat-pump tariff with off-peak rates dropping closer to 15p per kWh — Octopus Cosy, OVO Heat Pump Plus and EDF’s heat-pump tariff all sit in this range in 2026 — the annual heat cost can fall to £600 or below. The standing charge for electricity is higher than for gas, but if the home goes all-electric and the gas supply is capped off (savings of around £115 a year), the comparison stays roughly even on standing charges.
Net of standing charges: a 2026 gas combi runs at roughly £980 a year on this house. The same house on a heat pump runs at £600 to £900 a year depending on tariff. The cheaper end of the heat pump range is now consistently cheaper than the gas option. This is new.
Will it work in your house? The fabric question
A heat pump runs water around your house at lower temperatures than a gas boiler — typically 45–55°C compared with 65–75°C. That is why it is efficient, and that is also why it needs the rest of the house to cooperate. If your walls are uninsulated solid Victorian brick, your loft has 100mm of crumbling 1990s fibre, and three of your radiators were sized for the old back-boiler in the 1980s, a heat pump will run but it will run hot and cycle hard and you will not get the SCOP your installer modelled.
The shortlist of things to check first: loft insulation at 270mm, cavity walls insulated if they exist, double glazing throughout, and a radiator audit. Most installers will do a radiator audit as part of the survey and tell you which need swapping. Do not accept an install where the installer has not done a room-by-room heat-loss calculation under MCS 3005 — that document is the single biggest predictor of whether the system will hit its predicted SCOP.
The bit nobody quite says out loud
Here is the bold version. In 2026, in an averagely insulated UK semi with cavity-wall insulation and a half-decent loft, a heat pump is now the better long-run choice — and the gas industry, the boiler manufacturers and a chunk of the trade press still have not caught up to that arithmetic on the page. The Boiler Upgrade Scheme grant remains live, the unit-rate gap has narrowed, the install quality has improved, and the resale value of a heat-pump-equipped home with an EPC B or high C is now demonstrably higher than its gas-fired equivalent on the same street. The reason most homeowners still pick a like-for-like combi swap is not that it is cheaper over ten years — it usually is not. It is that it is quicker, cheaper this week, and does not require thinking about radiators. Both are valid reasons. They are not, however, the same as “the boiler is the better answer.”
The four scenarios where the answer is clear
A 1930s semi with cavity-wall insulation, double glazing, decent loft cover and radiators no smaller than single panel + convector: heat pump, almost every time, in 2026.
A solid-walled Victorian terrace with single-skin brick, no loft insulation, single glazing on the back extension and no plan to retrofit before installing: keep the gas boiler, replace it like for like if it is failing, and revisit when you do the fabric work.
A new-build under the Future Homes Standard, or a fully retrofitted home with mechanical ventilation and an EPC of B or better: heat pump, with no real conversation needed.
A rural home off the gas grid currently running an oil boiler: heat pump, almost always, because you are already on electric standing charges and the oil-versus-electricity comparison is even more favourable than gas-versus-electricity.
What to do in the next 30 minutes
Find your most recent gas bill or smart meter readout and note your annual gas consumption in kWh — the figure is on every annual statement. Find your electricity unit rate and standing charge on the same document. Look up your EPC at gov.uk/find-energy-certificate and note the band: anything C or better means the fabric is heat-pump-ready; D may or may not be; E and below need work first. Then book a free MCS heat-pump survey — Octopus, British Gas, Heat Geek and most regional installers run them — and ask specifically for a written room-by-room heat-loss calculation, not a ballpark. That document is the deciding evidence.
Keep your boiler records where you can find them
Whether you replace the boiler, install a heat pump, or do nothing for another two winters, the paper trail matters. The annual service, the Gas Safe certificate, the warranty, the magnetic filter clean — these are what a buyer’s surveyor asks for, what a heat-pump installer needs to size your replacement, and what a manufacturer asks for when a part fails inside the warranty period. Home+ is a free digital logbook for your home: save your boiler service history in Home+ and the next person who needs it — including your future self — can find it in under a minute, not by trawling the kitchen drawer or the loft.
FAQ
Is a heat pump cheaper to run than a gas boiler in 2026?
In an averagely insulated UK home on a dedicated heat-pump tariff, yes — typically £100 to £350 a year cheaper depending on the tariff, the SCOP and the home’s heat loss. On the standard electricity cap with no special tariff, it is close to parity rather than a clear win.
Will I lose the £7,500 Boiler Upgrade Scheme grant if I delay?
The scheme is funded through to 2028 at the £7,500 rate at the time of writing, but funding pots have been topped up rather than expanded, and there is no guarantee the rate stays the same beyond the current spending review. If the survey looks good, applying inside 2026 is the safer bet.
Do heat pumps work in cold UK winters?
Yes — modern air-source units are tested to perform down to minus 15°C and the UK rarely sees that for sustained periods. SCOP figures already account for cold-snap performance. Output drops in extreme cold, which is why the heat-loss calculation matters.
How long does a heat pump last compared with a gas boiler?
A correctly maintained air-source heat pump should last 15 to 20 years; the compressor is the wear part. A modern condensing gas combi typically lasts 12 to 15 years with annual servicing. The economic lives are closer than the prices suggest.
Can I install a heat pump without changing my radiators?
Sometimes. If your radiators are already generously sized — common in older houses where they were specified for low-efficiency boilers — the installer may keep them. If they are undersized, expect one or two upgrades. The MCS 3005 calculation is what tells you.
What about hybrid systems — heat pump plus gas boiler?
Hybrids exist and can suit poorly insulated homes where a full heat-pump install would underperform. They are more complex to commission and do not currently attract the same grant amount. Useful as a transition, less compelling as a long-term answer.
