Heat pumps · Home heating
Heat pump vs gas boiler: which is right for your home?
A heat pump can use far less energy than a gas boiler, but electricity costs more per unit than gas and installation is more involved. This guide shows how to compare the two fairly using your home’s heat demand, current prices and realistic system efficiency.
Updated 23 September 2026 · energy.org.uk editorial team
The short answer
A heat pump is usually the lower-carbon option and may have lower running costs when it is well designed, runs efficiently and uses a suitable tariff. A modern gas boiler is normally simpler to fit in a home that already has gas, but it burns a fossil fuel and its running cost depends heavily on gas prices and real-world boiler efficiency.
There is no single winner for every property. The most useful comparison is the cost of one kilowatt hour of useful heat, not the headline price of one kilowatt hour of gas or electricity.
At a glance
| Question | Air source heat pump | Gas boiler |
|---|---|---|
| Energy source | Electricity plus heat from the outside air | Mains gas |
| Typical conversion efficiency | Expressed as an annual SPF; often around 3 or more units of heat per unit of electricity | Less than 100%; a typical new boiler may average about 85% in use |
| Heat delivery | Steady, lower-temperature heating works best | Can deliver higher flow temperatures and faster warm-up |
| Hot water | Usually needs a cylinder | A combi can provide hot water without a cylinder |
| Installation | Outdoor unit, system design and sometimes radiator or cylinder changes | Usually more straightforward when replacing an existing gas boiler |
| Current support | Boiler Upgrade Scheme may contribute £7,500 in England and Wales, subject to eligibility | No equivalent Boiler Upgrade Scheme grant for a replacement gas boiler |
| Direct household emissions | No fuel is burned at the home | Produces carbon dioxide when gas is burned |
How to compare running costs properly
Gas and electricity prices cannot be compared unit for unit because the systems turn purchased energy into useful heat at different rates.
Gas boiler formula
cost per useful kWh of heat = gas unit rate ÷ seasonal boiler efficiency
If a boiler operates at 85% seasonal efficiency, divide the gas rate by 0.85. Remember that laboratory or product-label efficiency is not always the same as annual efficiency in a real home.
Heat pump formula
cost per useful kWh of heat = electricity unit rate ÷ seasonal performance factor
The seasonal performance factor, or SPF, estimates how much heat the system delivers for each unit of electricity over a year. It is more useful for annual cost estimates than a single coefficient of performance measured under one set of conditions.
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Heat pump vs gas boiler running costs
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How this was calculated
We estimate how much heat your home needs in a year: from your own fuel use if you gave it, otherwise from typical use for the type and size of home, anchored on Ofgem's typical household gas use.
Your current system turns fuel into heat at about 85% efficiency. A heat pump typically delivers about 2.8 units of heat for each unit of electricity across a year, in line with UK field trials, and a little less for hot water.
Prices: current Ofgem price cap, GB average, Direct Debit, for electricity and gas. Standing charges are left out unless you choose to remove gas. Installation costs are not included.
Method version 1.0, checked 2026-10-02. Ofgem typical use · Electrification of Heat trial
Installation cost and grants
Energy Saving Trust currently gives about £12,000 as a typical air source heat-pump installation cost. The final quote can move substantially depending on property size, heat loss, electrical work, radiator changes, pipework and hot-water storage.
In England and Wales, the Boiler Upgrade Scheme currently offers £7,500 towards an eligible air-to-water or ground-source heat pump. It also offers £2,500 for an eligible air-to-air heat pump. The installer applies for the voucher and eligibility rules apply. The scheme does not fund a hybrid system combining a fossil-fuel boiler and a heat pump.
Do not compare a heat-pump quote with an online “boiler-only” price unless both quotes cover the same work. Check whether they include the heat-loss survey, controls, cylinder, radiators, electrical changes, removal of old equipment, commissioning and warranties.
What determines heat-pump performance?
The equipment alone does not decide the result. The system design and the way it is operated are crucial.
Important factors include:
- the home’s calculated room-by-room heat loss
- radiator or underfloor-heating size
- the flow temperature needed on a cold day
- weather compensation and control settings
- outdoor temperatures in the local area
- hot-water settings
- installation and commissioning quality
- whether the household tries to use it like an on-off boiler
A competent installer should calculate a design SPF for the property and share it before work begins. Ask to see the assumed outdoor design temperature, heat loss, flow temperature and emitter schedule rather than accepting a generic efficiency claim.
Comfort and space
Heat pumps normally work best by maintaining a steadier indoor temperature for longer periods. Radiators may feel warm rather than very hot. That does not mean the system is failing if the rooms reach and hold their set temperatures.
An air-to-water system usually needs an outdoor unit and a hot-water cylinder. Some homes will need larger radiators or other changes. A gas combi boiler can be more compact inside the home and can produce hot water on demand, but it also needs a gas connection and flue.
Ask an installer to explain noise limits, unit position, condensate drainage, maintenance access and any planning restrictions, especially for listed buildings or conservation areas.
Which homes tend to suit each option?
A heat pump may suit you if:
- you want to reduce fossil-fuel use and household heating emissions
- the property can maintain comfort at relatively low flow temperatures
- there is space for the outdoor unit and, for most air-to-water systems, a hot-water cylinder
- you are willing to use steady controls rather than short, high-temperature heating bursts
- the quote and grant leave an acceptable upfront cost
- you can access a tariff that works with your heating pattern
A replacement gas boiler may be the more practical short-term option if:
- the property needs major changes before low-temperature heating will work well
- there is no suitable location for a heat-pump unit or cylinder
- the remaining cost after grants is unaffordable
- the home is already connected to gas and the priority is the least disruptive immediate replacement
That is not a recommendation to delay fabric improvements. Insulation, draught reduction and properly sized heating controls can reduce energy use whichever system is installed.
Questions to ask before accepting a quote
- What is the room-by-room heat loss and design outdoor temperature?
- What SPF is predicted for this exact design?
- What flow temperature is assumed at the design condition?
- Which radiators, pipes, cylinder or electrical components will change?
- What does the price include and exclude?
- What happens if the completed system misses the design temperatures?
- What product and workmanship warranties apply?
- Is the installer and installation eligible for the grant being quoted?
Frequently asked questions
Is a heat pump cheaper to run than a gas boiler?
It can be, but not automatically. Compare electricity price divided by the heat pump’s annual SPF with gas price divided by the boiler’s seasonal efficiency. A strong design, suitable controls and a well-matched tariff can move the result in the heat pump’s favour.
Do I need to keep my gas connection?
Not for an all-electric home. If gas is used only for heating and hot water, removing the connection may avoid the gas standing charge. Keep it in the model if a hob, fire or another appliance will still use gas.
Do heat pumps work in cold weather?
Yes, when properly sized for the property and local design temperature. Their efficiency changes with outdoor temperature, which is why annual SPF and a room-by-room design matter more than a single brochure figure.
Will all my radiators need replacing?
Not necessarily. The installer should calculate each room’s heat loss and the output of its emitter at the proposed flow temperature. Some radiators may already be large enough; others may need changing.
Can I get a grant for a heat pump?
Eligible properties in England and Wales may currently use the Boiler Upgrade Scheme. Scotland and Northern Ireland have different arrangements, so check the scheme for your nation rather than assuming one UK-wide grant.