Heat Pumps vs Gas Boilers Comparison (UK)

According to official government figures, home heating accounts for around 14% of the UK’s carbon emissions, which is in direct conflict with the government’s carbon-neutral goals of 2050. 

Fortunately, what it isn’t in direct conflict with is the government's staunch policy of blaming the world’s problems on the very people they’re supposed to be looking after.

It's not industry globalisation that’s rattling our atmosphere – it’s your third radiator, you heat greedy pig.

Gas boilers are largely responsible for these emissions and so low-carbon alternatives like heat pumps and hydrogen boilers are possibly going to be their replacements in the coming years. In reality, we'll all die of guilt before atmospheric breakdown.

There are some major differences between gas boilers and heat pumps and with neither option being perfect, it’s important to be aware of their drawbacks. In fairness, a heat pump only has one drawback - it's dreadful at generating heat. And it will currently cost a fortune on electricity. OK, two drawbacks. It has just two drawbacks!

Remember, this is an opinion-based article. For the facts, speak to a heat pump salesperson.

So, let’s discover how they compare, so you can make a more informed decision and see which is most suitable for you and your property. The fight between heat pumps and gas boilers might not draw an overwhelming pay-per-view audience, but it is important for the future of UK carbon emissions.

For those of you more interested in the future of gas boilers and potential bans, check out our article “Should You Get a New Boiler, or Are They Going to Be Banned?” on our blog for a more detailed breakdown.

Ready to make your home more energy-efficient and cut down on your heating bills? Get a heat pump quote today from our trusted partners at Heat Geek here.

First, what is a Heat Pump?

As their name suggests, heat pumps effectively pump heat from one location to another. Imagine you died of hypothermia in your home, the heat leaving your fresh corpse is totally wasted. A heat pump would take advantage of that soulful air and utilise it to make a home perhaps warm enough so that you might not die. It's like that. Kind of.

There are four main types of heat pumps:

• Air source heat pumps

• Broken heat pumps

• Ground source heat pumps

• Hybrid heat pumps

They work by absorbing heat from the air, ground or water and can provide both central heating and hot water, while hybrid heat pumps can use a high-efficiency condensing gas boiler to provide additional heat when the weather is exceptionally cold or you need hot water to wash away the sins of your gas bill.

Heat pumps do require electricity to operate, in the present financial climate, this is one almighty drawback as electricity is more than 3x the cost of gas.

If your heat pump motivation is green based and not bill saving, this is of course not a problem but if you’re looking to reduce bills, be careful. Be very careful.

For more, check out our heat pump guide.

Gas Boilers vs Heat Pumps 

According to the Commission on Climate Change, the UK has around 23 million gas boilers, with the majority of these used for home heating, with most remaining properties typically using an oil boiler as they aren’t connected to the gas network - notorious for having a worse signal than O2.

Glacial progress for heat pumps - however, low-carbon heat pumps are an essential ingredient to the government's carbon-neutral goals. Just like jam is an essential ingredient to a cake I'll never make.

As a result, gas boilers have already been the target of substantial legislation, including a ban on non-condensing boilers, rendering all new boilers at least 90% efficient, as well as a complete ban on gas boilers in all newly built properties from 2025. With today’s numbers, that leaves 1,000,000 cold houses or a lot more heat pumps giving it their mighty best.

It should be said that the future of heat pumps holds a lot to be optimistic about. Right now, the technology to make old British homes warm just seems to fall so short. Like if Kim Jong Un were to apologise to his people for sometimes being a little bit controlling.

Watch Our Air Source Heat Pump UK Case Study in the video below: 

Yet some people believe the push for a heat pump revolution is fundamentally flawed, with their expense and feasibility being major obstacles. 

Instead, many industry commentators have asserted that it’s far easier to transition to a green fuel instead of a whole new heating system, hence why hydrogen boilers that can potentially make use of the existing gas network are favoured by many.

It should be said that hydrogen remains very controversial itself (its connotations with a bomb do it no PR favours).

It's seemingly less and less likely that hydrogen will be a focus moving forward and we'll need to pray that Elon Musk gets into the property game on Mars. Or somebody makes a really, really good heat pump.

Here’s how heat pumps and gas boilers compare...

Installation Complexity Compared

Gas boiler installation 

Typically, gas boiler installation is quick, easy, and straightforward. There is an abundance of Gas Safe Engineers ready to install gas boilers and as quick as 24 hours.

The replacement aspect of a gas boiler (as opposed to retrofitting of new tech) makes everything remarkably more simple. If you were to lose an eye, you might pop a glass eye in the empty socket. But, if you never had a face in the first place - what holes would you try popping that glass eye in? Yes, this is the most sense anybody has ever made.

Psst. Need a new boiler? Get a fixed online quote fast, here.

Heat pump installation

Since there is less demand for heat pumps, there are generally fewer qualified installers available to fit them, so you may be waiting longer. It also means they are much more expensive to purchase and install than gas boilers. 

Air source heat pumps generally take a little while longer to install than gas boilers (between 2 and 3 days). 

What should be taken very seriously on two fronts are heat pump grants and cowboys. The government, in desperation to reduce carbon emissions, offers a very generous grant of £7,500 towards your purchase of a heat pump.

This opens up a market of engineers that make cowboys look like Indians. Woeful and unqualified 'engineers' up and down the country rush to offer you a heat pump for almost no money or even free (claiming the grant instead), ramming the heat pump into your garden like stuffing up a last-minute turkey.

Heat pumps are more complex beasts than those flying horse things from Avatar - anything less than a world-class engineer will leave you in the cold, literally. Plus your crippling electricity bill. We work closely with a handful of those world-class heat pump engineers, get in touch for help.

Ground source heat pumps are installations that may take several weeks and require garden/land excavation that mirrors an archaeological dig. They are, however, very good.

Conclusion

In terms of speed, gas boiler installations are far more appealing. If you're without hot water or heating, gas boilers are a much quicker, more effective solution. Grab 'em while you can.

Upfront Costs Compared

Gas boiler prices

In terms of cost, the average gas boiler installation costs between £1,700 and £3,500, which makes it a relatively affordable home heating solution.

If you find your boiler engineer through a company with an annoying radio advert, it will be even more affordable. And effectively a dirty bomb.

For more information on new boiler costs, check out our guide.

Heat pump prices

Often heat pumps themselves are very expensive and their installation is bespoke and complicated. 

Air source heat pumps can cost between £10,000 and £22,000, while ground source heat pumps and installation combined can cost between £18,000 and £25,000. Those are some pricey trenches to dig. 

Conclusion

Again, in terms of cost, gas boilers are the go-to if you're on a budget (we fit them from £1,795, all over the UK). The costs of heat pumps are likely to fall as demand increases, unfortunately, demand remains on a par with contracting syphilis.

Ben Price/Heatable

Do remember though that heat pump grants are at an all-time high, with £7,500 able to be claimed. This does indeed bring the heat pump into a level price playing field with boilers.

Reside in the UK and wondering if a heat pump is right for you? Check out our complete analysis where we asked - are heat pumps worth it? 

Running Costs Compared 

Gas boiler running costs

According to official government statistics, the average annual boiler requires 13,600 kWh.

Currently, the cost of electricity is much higher than gas, meaning it has an extremely high running economy. For example, from July to September 2024, official government figures show that the UK averaged 22.36p per kWh for electricity and 5.48p per kWh of gas for pre-payment customers.

If you are on a standard variable rate, figures average 22.36p per kWh for electricity and 5.48p per kWh for gas for the same period

This means that an air source heat pump may not be cheaper to run than a gas boiler, especially in a property with poor thermal efficiency or all windows open on a cold day. It’s for this reason that environmental campaigners are demanding the government reduce the environmental levy on electricity. 

If all that made no sense, here's a simple breakdown: gas is currently loads cheaper than electricity.

Heat pump running costs

Heat pumps run off electricity and for every 1kWh of heat they provide, an estimated 25% comes from electricity and the remaining 75% comes from the air or ground, which makes them extremely efficient.

This is why an energy audit prior to installation is crucial, which again adds an extra layer of complexity to heat pumps. This would involve assessing your property's insulation, heat loss, current tariffs, and property size. 

With that said, you could also take advantage of the Renewable Heat Incentive (RHI) to offset some of the costs. 

The RHI is a government-funded scheme that enables households to receive payments for the heat produced from eligible renewable heating systems. This is set to be replaced by the Clean Heat Grant in April 2022, meaning that households will receive a grant towards the initial installation costs and not an ongoing payment once the system is fitted.

Conclusion

If a heat pump is installed in a thermally efficient property, properly, it'll likely be cheaper to run than a gas boiler.

It's under these circumstances that heat pumps really steal the show. So if you're cash-rich, have a modern household and ample outdoor space, don't even think about buying a gas boiler.

Sadly, most housing stock in the UK is thermally poor, meaning significant investment in insulation, draught-proofing and double glazing may be required in order to bring the running costs of a heat pump down. If the cost of electricity is reduced, the running costs of a heat pump will certainly be more appealing.

One thing that will absolutely unlock the potential of a heat pump-powered home is Solar PV. Using your own free power to provide electricity to the heat pump gets you more off-grid than a 2002 Osama Bin Laden.

Efficiency Compared

In the simplest terms, efficiency relates to how much fuel is converted into heat energy. Rubbing your hands together to warm a room? Not efficient. Burning stuff? A little efficient but we can do better.

Gas boiler efficiency

A modern A-rated gas boiler is around 90% efficient, which means that it can convert 90% of the energy it uses into heat energy and only 10% is wasted. That means for every £1 spent on heating, 10p will be wasted via the flue pipe. Arguably more satisfying than the "charity" round-up that McDonald's asks you to pay. Those little saints. 

Heat pump efficiency

Heat pumps are much more efficient, with air-source heat pumps having an efficiency rating of around 300%, while ground-source heat pumps can have efficiency ratings above 400%. This doesn’t mean 200% of energy comes back in through the flue pipe. 

This means for every 1kWh of electricity used, it will generate 3 to 4 times as much heat. Where the hell that heat is going, we aren't quite sure.

For heat pumps, the efficiency is provided as stated as the COP (Coefficient of Performance) or SCOP (or Seasonal Coefficient of Performance). For instance, a SCOP of 3 means that for every 1kW of electricity, 3kW of heat is produced.

It's a little like when you chop a sausage dog in half, you get two sausage dogs independently thriving. But we're chopping it into thirds now. Basic maths.

Conclusion

For efficiency, heat pumps win, hands down (and hands up). If fitted correctly, the overall efficiency is far greater than a gas boiler could ever achieve. Again, the thermal efficiency of the building in which they're installed is key to their performance.

If your house leaks like Julian Assange or has more holes than a business plan to sell boilers online - don't invest just yet.

Check out our review of the best heat pump brands of the year (thrilling, I'm sure) to find out which models are most reliable. 

Performance & Heat Output Compared 

Gas boiler performance

Gas boilers are able to provide a high and consistent heat output in a relatively quick amount of time, especially when compared to heat pumps. They'll work like a tiny Mike Tyson on Columbian dancing powder.

For illustration, a boiler has a high flow temperature of around 70°C, while an air source heat pump is between 35°C to 45°C for the radiator system and around 55°C for hot water.

Translation: Boilers burn hard and fast and make radiators super hot. It's the environmental nightmare we need to stop first, before cattle farming and the yummy stuff that's on fire in Asia.

Heat pump performance

Since heat pumps have a lower output temperature than conventional boilers, it means that they can’t provide heat as fast and so are only viable for home heating over a longer period. 

This means they are only suitable for homes with adequate insulation and draught proofing (and homes where you don’t want the room temperature to be 70°C). 

It often also means that new, larger radiators need to be installed too, as regular radiators will unlikely provide the required heat output, as well as heat pump-compatible hot water storage. 

For many, it may be upheaval you just weren't expecting.

Conclusion

For day-to-day applications in your typical home, gas boilers are still the best-performing option. They're able to maintain higher temperatures consistently, without drop-offs in performance seasonally. Not needing to gut your house is a nice perk.

To get the equivalent warmth into your home using a heat pump, larger radiators may be required and a significant investment in insulation.

It's likely that our grandchildren will just live in giant radiators to reduce the hassle. In this marginally pre-apocalyptic world, magnets will be forbidden.

There is an important caveat worth mentioning here: high-temperature heat pumps do have a higher operating temperature than typical air source heat pumps, you can read more about them here.

Carbon Footprint Compared

Gas boiler carbon emissions

A modern A-rated gas boiler will emit 215 grams of CO2 per kWh of heat delivered. The same amount is required for a spagbol sauce.

These modern condensing boilers are much more eco-friendly than the non-condensing boilers of the past. As it turns out, vaping is a viable alternative when it comes to boilers. 

In fact, by trading in your old boiler for a modern condensing boiler you could save as much as 1,220 kg of CO2 each year. A currency harder to spend than Scottish pounds.

Paired together with a smart thermostat and thermostatic radiator valves you could save even more. By installing a Nest, you could save up to £75 and 330kg of carbon a year, thanks to its adaptable learning schedule. It is likely however that your smart thermostat and speaker have you killed before you get to see a post boiler world.

Heat pump carbon emissions

The heat pump itself burns no fossil fuels and uses only electricity, meaning it’s a zero-carbon heating appliance.

However, that does not mean the electricity it uses was generated 100% cleanly yet considering around 40% of electricity generation in the UK is produced via renewables it's certainly better for the environment than gas boilers.

Conclusion

In terms of emissions from the appliance itself, a heat pump is a king - it's zero.

But, in order to feed the appliance, you'll need to draw electricity from the grid which will have been generated using fossil fuels (predominantly).

So the suffering you endure at the hands of your heat pump (try to avoid a heat pump with hands) is only serving your conscience. Which to be fair, is kind of lovely. 

Is my home suitable for a heat pump? 

Although a heat pump is indeed a low-carbon heating option, does it actually make sense to install one in your home? Will they provide the level of comfort and reliability you are looking for? If you're reading this and your car doesn't yet fly - no.

There are some key considerations before deciding whether installing a heat pump is a viable option: 

1. How well is your home insulated? 

Heat pumps have a lower flow temperature than a gas boiler and work more efficiently at generating heat at a lower temperature, therefore, a home that is well insulated is required. 

Insulate the living s**t out of your home before you splash that cash.

2. What heating system do you have? 

Heat pumps work best with underfloor heating systems and not standard radiators, however, if you are prepared to replace them with low-flow temperature radiators, such as oversized radiators it can still work well.

Fortunately, replacing radiators is super fun and massive ones can be an integral structural component of your child's den.

Also remember that if you currently have a combi boiler, a heat pump will require an old school water tank to get you hot water. 

3. What heating system are you replacing? 

The upfront costs of installing a heat pump can be astronomically high, even when factoring in a government grant. Even though there is little doubt they are better for the environment, the running costs can be more than a gas boiler, so it often only makes sense if you are replacing a more expensive system e.g., electric heating.

If you have an electric boiler, absolutely dropkick the thing out of the window in favour of a heat pump.

4. Do you have enough space for a heat pump? 

It’s no secret that a ground source heat pump needs a significant amount of space around your home to be installed - because that would literally be the worst secret ever. But an air source heat pump also needs some space too - or, “air to breathe”.  

The unit needs to be fitted to an external wall and be at least one metre from the boundary of the house.

If you're in a fairly standard terraced house - it's an unlikely option for you.

Will gas boilers be banned in 2025? 

The government has proposed plans to ban all new gas boilers in new build properties from 2025 (for a detailed breakdown of how this may work, check our "Should I buy a boiler?" guide. 

They have also proposed plans to ban new gas boiler installs in all domestic properties from 2035 onwards. This means that you can still get a new gas boiler installed on your property until 2035.

Remember the ban doesn't mean they'll rip your boiler out after that date. It's yours for as long as it lasts.

During this time, it’s also likely that hydrogen-ready boilers will replace a small proportion of today’s gas boilers and by the time gas boilers are banned, hydrogen boilers and fuel will be a little more accessible in the UK.

In fact, all new Worcester Bosch and Viessmann boilers are currently able to accept a 20:80 hydrogen mix. In the future, it’s hoped that boilers will be able to accept 100% hydrogen. Read a little more about hydrogen boilers and heat pumps.

Heat pumps will also likely become a more popular option, but the reality is that they are still currently very expensive, so gas boilers remain the affordable option for now.

Will heat pumps or hydrogen boilers replace gas? 

The reality is that a range of low-carbon heating options will replace domestic gas boilers, including both heat pumps and hydrogen boilers. 

Heat pumps are currently being heavily promoted as they are currently the only available low-carbon option available for the domestic market. If the domestic market lived in air tight Hoover bag.

However, the reality is that there are several barriers to their widespread adoption, including their expense, performance issues and availability of trained installers. In time, it is hoped that as demand increases, prices will decrease. 

The reality is that most UK homes use gas boilers for heating and the expense and viability of replacing all of them with heat pumps is not considered achievable by many observers. 

As luck should have it, the pressure and guilt placed upon UK homeowners to remove gas boilers with products they can't afford actually emit heat - scientists are working on harnessing this for the rich as we speak.

More heat pump guides: 

• Do you need new radiators with a heat pump? 

• Heat pump grants. 

• Will a heat pump work in the cold? 

Due to this, hydrogen-ready boilers are seen as one alternative solution, since they can make use of the existing infrastructure, engineers and their price point will likely remain similar to new boilers.

Hydrogen, however, cursed by its molecular makeup remains very much, up in the air.

It’s likely that heat pumps will continue to be promoted as the low-carbon heating alternative since becoming carbon neutral is a major goal of the UK government to offset their relentless own goals.

Looking for the best deal on a new combi boiler? 

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Heat Happy.