Gas boilers vs air source heat pumps

In the UK, the majority of buildings are heated using gas boilers. In fact, a whopping 17% of the UK’s total emissions output is represented by home heating (according to Energy UK)!

But the government is targeting a 15% reduction in energy consumption of buildings and industry by 2030. So, something has to change.

Here, we’ll compare everything you need to know about gas boilers vs air source heat pumps to help you understand whether a heat pump is really a valid alternative to your traditional boiler (hint: it definitely is!).

Gas boilers vs air source heat pumps: how do they work?

Both gas boilers and air source heat pumps work by pumping warm water round your central heating system or sending it to your taps and showers.

But the way they heat this water is different.

Gas boilers use a series of gas flames. Essentially, the water passes by these flames in pipes and heats up, just like how you might heat water in a pan when you’re cooking.

On the other hand, an air source heat pump extracts warmth from the air outside, which causes a refrigerant to evaporate and turn into gas.

This is then moved through a compressor to raise the temperature using a small amount of electricity, before it’s passed over an internal heat exchange surface to warm up the water that heats your home.

As you can see, gas boilers and air source heat pumps work very differently. But the way your space heating and hot water feels will be very much the same.

The main noticeable differences will be in things like running costs, longevity and sustainability. Which brings us onto…

Gas boilers vs air source heat pumps comparison

Heat pumps trump gas boilers in many regards. Not only are they efficient and sustainable, but they’re also futureproof – as heat decarbonisation is crucial for the government’s Net Zero goals.

But don’t just take our word for it.

Here’s how they compare on key points.

Environmental impact

Gas boilers are a real problem for the environment.

According to The Guardian, the millions of gas boilers in the UK’s homes produce twice as much climate-heating carbon emissions as all the nation’s gas-fired power stations combined.

And that doesn’t even include the boilers used in commercial and industrial settings!

On the other hand, heat pumps are an environmentally friendly heating method.

Firstly, they’re sustainable – they use the air to provide heat, which is a natural energy source.

And secondly, they don’t produce emissions.

The only thing to think about is the refrigerant that your heat pump uses. Most heat pumps manufactured today still contain synthetic refrigerants like HFOs and HFCs.

These are largely F-gases that have a high global warming potential (GWP) and also release harmful forever chemicals known as PFAS into the environment.

However, this can easily be solved by opting for a natural refrigerant heat pump instead.

At Clade, we only use natural refrigerants in our heat pumps as they’re non-toxic, have a very low GWP and have zero ozone depletion potential (ODP) – making them a no-brainer for both people and the planet.

Future

With climate change a major concern in today’s world, heat decarbonisation is slowly but surely moving up the government’s priority list.

Already, boiler bans are in place in 11 countries (according to Nesta).

And in the UK, gas boilers will begin to be phased out from 2025, when they will no longer be an option for new builds.

In this way, there’s a real chance that a new gas boiler could become a stranded asset in the not-too-distant future.

Meanwhile, opting for a heat pump instead could be a great way to safeguard your heating system’s longevity.

The only regulations that could affect you are likely to be around F-gases if you choose a heat pump that contains a synthetic refrigerant.

However, by simply opting for a natural refrigerant heat pump instead, you can gain peace of mind that your heat pump will be a futureproof heating system.

Efficiency

Air source heat pumps are a whopping three or four times more efficient than gas boilers.

The most efficient gas boilers can reach around 98% efficiency.

Meanwhile, air source heat pumps can reach around 300% efficiency.

This is because heat pumps don’t actually generate heat from scratch like a gas boiler does. Instead, they transfer heat from one place to another, using just a small amount of electricity.

In fact, just 25% of the energy used by an air source heat pump is typically provided by electricity, with the rest being generated by the environment.

Head over to our dedicated guide on heat pump efficiency to learn more.

Running costs

Given how efficient heat pumps are, they also come with lower running costs than gas boilers.

Remember, most of the energy an air source heat pump uses is generated by the environment through the air – which is free!

Of course, you’ll still have to account for the electricity used.

However, heat pumps generate more heat than the electricity that powers them, allowing you to keep your energy bills down.

You can lower your energy bills still more by using a renewable energy source like solar panels to generate the electricity used.

But even without this, the electrification of heat by using a heat pump opens up the opportunity to use power at times when it’s cheap – known as grid flexibility.

Oversizing your thermal store makes this an even better opportunity, and can dramatically cut utility costs by up to 20%.

With all this in mind, heat pumps won’t just lower your energy bills, but they’ll also give you more control.

Upfront cost

Gas boilers are still significantly cheaper to install than heat pumps – which largely comes down to the fact that heat pumps are still a relatively new heating technology.

Data from the Microgeneration Certification Scheme (MCS) reveals that a total of 250,000 certified heat pump installations have now been completed in UK homes (according to Current).

This shows that they’re increasing in popularity – but it’s still far, far less than the number of boilers being installed. In fact, the Department for Business, Energy & Industrial Strategy states that up to 1.7 million domestic-scale natural gas boilers are installed in the UK every year!

According to The Guardian, the upfront cost of a heat pump is likely to be around four or five times more than the cost of a gas boiler (including both supply and installation).

However, it’s worth noting that this gap will slowly close over time.

And, until it does, there are schemes available to help towards the cost of a heat pump – designed to incentivise homeowners and businesses to make the switch.

For domestic heat pumps, help is available in the form of schemes like the Boiler Upgrade Scheme and the Energy Company Obligation (ECO) scheme.

Meanwhile, grants and funding schemes available to organisations include:

• Public Sector Decarbonisation Scheme (PSDS)
• Clean Heat Grant
• Boiler Upgrade Scheme (BUS)
• Social Housing Decarbonisation Fund (SHDF)

… although the only government support widely available to non-public sector organisations are tax breaks (it’s likely that heat pumps will qualify for the 50% first year allowance (FYA) for special rate plant and machinery – although bear in mind that we’re not tax advisors!).

Alternatively, we can also help most businesses to spread out the initial cost of an air source heat pump with commercial heat pump financing.

Installation

Approximately 85% of residential buildings are connected to the national grid, using a boiler and wet-based central heating system (according to the Committee on Climate Change) – and this applies to countless more business premises.

With that in mind, installing a new gas boiler is typically quick and easy. After all, the likelihood is that your building is already set up for one!

On the other hand, you may need to make more changes to accommodate a heat pump. But retrofitting a heat pump is a lot easier than you might think.

It all comes down to choosing a refrigerant with a similar temperature differential (Delta T) as those used by traditional boilers – like the natural refrigerant R290 (propane).

This reduces the number of changes that you’ll need to make to your building’s existing infrastructure, minimising disruption and cutting installation costs.

Most of the time, you’ll just need to replace your building’s radiators to accommodate the lower flow temperatures – but sometimes, even this isn’t necessary.

For buildings where it isn’t possible to make changes to the heating system (such as listed buildings and healthcare facilities), we even offer a high temperature heat pump, the Elm – which is designed to be a direct replacement for a traditional gas boiler.

This allows for easy installation and reduces disruption so that businesses can operate continuously while having a heat pump installed.

Longevity

On average, you can expect a heat pump to last double the lifespan of a typical domestic boiler.

As a rough guide, boilers typically last around 10 to 12 years.

Meanwhile, heat pumps should last over 20.

This is because heat pumps have a robust design with minimal moving parts – which also means they need very little maintenance.

At Clade, we also offer regular heat pump maintenance to help you keep your heat pump in optimal condition and maintain its efficiency.

As part of this, one of our qualified engineers will inspect your system yearly, which can prolong the life of your heat pump system even more.

Usability

One of the biggest benefits of gas boilers is that they’re a technology that most of us are familiar with.

In this way, it doesn’t take much brainpower for most of us to figure out how to use them.

That said, heat pumps are also easy to control – it’s just about getting used to a new heating technology.

Heat pumps can typically integrate with a range of controls, including as part of a wider climate-controlled system.

And at Clade, the majority of our heat pumps are also remote monitoring and smart enabled.

This means our experts can monitor your heat pump’s performance remotely from our headquarters in Leeds and make any necessary adjustments for you, to ensure your heat pump is operating as efficiently as possible.

Air source heat pumps vs gas boilers pros and cons

As you can see, heat pumps have the edge over gas boilers in nearly all aspects.

However, they both have their pros and cons.

Here’s a quick summary – you can also head over to our guide on the major heat pump benefits to learn more.

Air source heat pump pros

• Sustainable
• Futureproof
• Efficient
• Low running costs
• Grants and funding available
• Easy to retrofit
• Long lifespan
• Controllability

Air source heat pump cons

• High upfront costs
• Not as easy to retrofit as gas boilers

Gas boiler pros

• Low upfront costs
• Easy to retrofit (in a building that’s set up for it)
• Familiar technology

Gas boiler cons

• Bad for the environment
• Soon to be phased out

• Less efficient
• Higher running costs
• Shorter lifespan

Switching from a boiler to an air source heat pump: case studies

Still not sure whether to take the plunge and replace your gas boiler with an air source heat pump?

Here are three case studies that demonstrate the positives of making the switch.

Claremont Resource Centre

Claremont Resource Centre is a vital community hub located in Manchester. With the help of PSDS funding, they replaced their outdated gas boiler with a Clade CO2 heat pump system in order to enhance energy efficiency and reduce carbon emissions.

Head over to the full Claremont Resource Centre case study to learn more.

Chelsham House

Chelsham House is a residential NHS ward that needed to replace its old gas boilers with an efficient and sustainable heating system, without making extensive modifications to its existing infrastructure. A pair of our advanced propane heat pumps was just the ticket.

Read the full Chelsham House case study for more details.

Stanley Library

Stanley Library, a public building with a rich history, wanted to modernise its heating system with a solution that was not only efficient but also sustainable. Our Acer CO2 heat pumps were the perfect solution, reducing energy consumption while working at their most efficient at all times.

Check out the complete Stanley Library case study for the full story.

So, which is better: a gas boiler or an air source heat pump?

Both gas boilers and air source heat pumps have their pros and cons.

However, air source heat pumps trump gas boilers in nearly all regards – they’re efficient, eco-friendly and even come with low running costs.

Perhaps most importantly, they’re one of the only heating solutions that you can be confident will last long into the future as gas boilers start being phased out and the government works to achieve their Net Zero goals.

At Clade, we have 35 years of experience manufacturing efficient natural refrigerant heat pumps and refrigeration equipment.

So, if you’re a business with a mission to modernise your building’s heating system, you’re in the right place.

Simply get in touch to start the conversation.