Heat pump vs gas boiler: which is right for your home?

If your boiler's on its way out, or you're just weighing up your options, the choice usually comes down to two questions: what will it cost, and will it actually keep my home warm for less. It's worth knowing upfront that a heat pump install is a whole-system upgrade, not a straight swap of one box for another, and that shapes both the cost and the benefits below. Here's a straight comparison, so you can work out which one fits your home.

The short answer

A heat pump costs more to install than a straightforward gas boiler swap: typically £8,000 to £14,000 before the grant, against £2,500 to £4,000 for a like-for-like boiler. That's not quite comparing like for like, though. A heat pump install upgrades your whole heating system, typically including a hot water cylinder and any pipework or radiators your home needs to run efficiently, not just the appliance, which is where the broader comfort and efficiency gains come from. Running costs are close today on a standard electricity tariff, and often lower if you're coming off oil, LPG or an old, inefficient boiler. Day to day, a heat pump also feels different: a steadier, gentler warmth rather than short, hot bursts. The £7,500 government grant (£9,000 for off-grid homes from 21 July 2026) narrows the cost gap considerably.

At a glance

• Installation cost: £2,500 to £4,000 for a gas boiler swap; £8,000 to £14,000 for a heat pump before the grant. Not a direct comparison - see below.

• What the price covers: a boiler swap replaces the appliance only; a heat pump install typically also covers a hot water cylinder and any pipework or radiator changes your home needs to run efficiently.

• Running cost today: usually cheaper on mains gas; close on a standard electricity tariff, and often lower for a heat pump if you're coming off oil or LPG.

• Day-to-day comfort: a boiler heats in short, hot bursts; a heat pump runs more gently and continuously.

• Efficiency: around 90% for a modern A-rated gas boiler; more than three times as efficient for a heat pump, since it moves heat rather than burning fuel.

• Typical lifespan: 10 to 15 years for both, with regular servicing.

• Grant available: none for a gas boiler; £7,500 for a heat pump, £9,000 for off-grid homes from 21 July 2026.

Installation cost: why it's not a straight swap

Replacing an old gas boiler with a new one in the same spot typically costs £2,500 to £4,000, supply and installation included. Swapping a system boiler for a combi, or anything that needs extra pipework, tends to land nearer £4,000. Either way, you're replacing one appliance with a newer version of the same thing.

A heat pump costs more upfront, typically £8,000 to £14,000 fully installed, but the comparison isn't quite like-for-like. That price generally covers the heat pump unit, a hot water cylinder, and any pipework or radiator upgrades your home needs to run efficiently at lower temperatures, not just a straight swap of the heat source. It's a whole-system upgrade, and that's exactly where the broader comfort and efficiency gains come from. The £7,500 Boiler Upgrade Scheme grant is deducted from your quote upfront by your installer, which brings many homes down to somewhere between £500 and £6,500, often close to the cost of a boiler replacement, even though you're getting considerably more for it. We break the full cost down in how much does a heat pump cost.

Running costs: which is cheaper to heat your home?

This is the question people actually want answered, and the honest answer is: it depends what you're replacing.

On mains gas, running costs are currently close between the two, and a heat pump can cost slightly more on a standard electricity tariff, because electricity costs more per unit than gas. Switch to an electricity tariff designed for heat pumps, and that gap typically closes or reverses.

If you're coming off oil, LPG or an old, inefficient boiler, a heat pump is usually the cheaper option to run, because those fuels already cost more per unit than mains gas, before you even factor in the heat pump's efficiency advantage. We go into the off-grid case in replacing an oil boiler with a heat pump.

Efficiency: why the comparison isn't like-for-like

A modern A-rated gas boiler runs at around 90% efficiency: for every unit of gas it burns, you get back a little less than one unit of heat. A heat pump doesn't burn anything, so its efficiency is measured differently. Rather than creating heat, it moves heat that's already in the outside air, and Energy Saving Trust puts a well-installed heat pump at more than three times as efficient as a gas or oil boiler.

That's why the running-cost comparison is closer than the efficiency gap alone would suggest: heat pumps use far less energy for the same warmth, but the electricity that powers them costs more per unit than gas. Get more detail on how that works in how do heat pumps work.

Comfort: what changes day to day

Much of this comes down to what a heat pump install actually changes. Because it's a whole-system upgrade rather than a straight appliance swap, correctly sized radiators, pipework designed for lower running temperatures and a properly designed system all come as part of the job, and that's what delivers the comfort gain, not just a new box outside.

A gas boiler heats your home in short, hot bursts, firing up, pushing heat out fast, then switching off. A heat pump runs at a lower, steadier temperature for longer stretches, warming your home gently and continuously rather than in spikes. Most people find it a more even kind of warmth once they're used to it, and it's quieter too: a modern air source unit runs at about the level of a quiet fridge.

There's a lower-carbon story here as well, since a heat pump runs on electricity rather than burning fuel in your home, and that gap only widens as the grid itself gets cleaner. It's a genuine, low carbon upside, not the main reason most people switch, but a welcome one alongside the comfort and the cost.

Which is right for your home?

There's no universal answer, but a few situations make the decision easier.

Your gas boiler still works fine. There's no need to rush. It's worth planning your next replacement around a heat pump rather than another boiler, given the direction of travel and the grant available right now.

You're on oil, LPG or heating a home with an old system. This is usually where the case is strongest. Off-grid fuels already cost more, and the higher off-grid grant lands soon.

You're renovating or building new. It's far cheaper to design a heat pump and the right emitters in from the start than to retrofit one later.

You want a steadier, quieter kind of warmth. If the cost case is close either way for your home, comfort day to day often settles it: a heat pump replaces short, hot bursts with a gentler, more continuous heat, and it runs quietly.

The grant that changes the sums

The Boiler Upgrade Scheme currently gives homeowners in England and Wales £7,500 towards an air source or ground source heat pump, deducted from your quote by your installer. From 21 July 2026 to 31 March 2027, eligible off-gas-grid homes (currently on oil or LPG) can claim £9,000 instead. There's no equivalent grant for a new gas boiler. Speak to an MCS-certified installer to check your eligibility before you commit either way.

Frequently asked questions

Is installing a heat pump the same as replacing a boiler? No. Swapping a boiler replaces one appliance with a newer version of the same thing. A heat pump install is a whole-system upgrade, typically including a hot water cylinder and any pipework or radiator changes your home needs, which is why it costs more but also delivers broader comfort and efficiency gains.

Is a heat pump cheaper to run than a gas boiler? On mains gas, running costs are currently close, and can be slightly higher on a standard electricity tariff. Coming off oil or LPG, a heat pump is usually the cheaper option to run.

Is it worth switching from a working gas boiler to a heat pump? If your boiler still works well, there's no need to replace it early. But when it does need replacing, a heat pump is worth serious consideration given the grant, the efficiency and the steadier, quieter warmth day to day.

How much does a heat pump cost compared to a new gas boiler? A heat pump typically costs £8,000 to £14,000 before the grant, against £2,500 to £4,000 for a like-for-like boiler swap. That's not comparing like for like, though: the heat pump price usually includes a hot water cylinder and any pipework or radiator upgrades your home needs, not just the heat source. After the £7,500 grant, the gap narrows considerably.

Do I need to replace my radiators for a heat pump? Not always. Some homes need a few larger radiators to run efficiently at lower temperatures; others don't. A proper heat-loss survey tells you which applies to your home.

Will a heat pump keep my home as warm as a gas boiler? Yes. A heat pump heats your home to the same comfortable temperatures, just more gradually and steadily rather than in short, hot bursts from a boiler.

Ready to compare for your own home?

The numbers above are typical ranges. What matters is what a heat pump would actually cost and save in your home. Get an instant estimate in minutes, with no survey and no obligation.