If you’re in the middle of weighing up whether to install a heat pump or a gas boiler in your home, then this article is for you.

We’ll be comparing the two systems in terms of their upfront costs, running costs, environmental impact, and whether heat pumps are cheaper to run than gas boilers, to help you make an informed decision about which option is best for you.

Also, if you are looking to replace your existing gas boiler with a carbon-neutral option, then a heat pump may be the way to go.

For context, the vast majority of newly built homes are choosing to install heat pumps over boilers since gas boilers will be phased out by 2025.

Manufacturers of boilers are also focusing on hydrogen-ready boilers to keep their businesses going after this date.

Let’s go through the differences.

What Is a Heat Pump?

There are two types of domestic heat pumps: air source and ground source.

Air source heat pumps extract heat from the outside air and use it to heat your home.

Ground source heat pumps take heat from the ground, using a series of underground pipes, and use it to heat your home.

Both options are considered low carbon heating options as they emit around 3-4% of the carbon emissions of a gas boiler and their lifespan is around 25 years.

Heat Pump Running Costs

Air source

It costs around 4.65p per kWh to heat a home with gas, 4.82p per kWh for oil, 7.70p per kWh for LPG, and 20.06p per kWh with standard electric heaters, according to the Energy Saving Trust (ESD). A typical air-source heat pump may cost 5.73p per kWh to run.

Power consumption

An air-source heat pump can create 3 kWh of heat per 1 kWh of electricity. The typical yearly energy consumption for most homes in the United Kingdom is 12,000 kWh. It will set you back around £520 each year in heating expenses if your electricity costs $0.13 per unit each year.

Heat pump efficiency vs temperature

Heat pumps lose efficiency when temperatures drop below 25 to 40 degrees Fahrenheit for most installations.

A heat pump is most efficient when the temperature is above 40 degrees.

When outdoor temperatures fall below 40 degrees, heat pumps begin to lose effectiveness and need more energy to perform their duties.

Related: What is the Efficiency of a Heat Pump?

Ground source

Ground source and air source heat pumps save money over conventional heating systems since their low running costs.

A ground source heat pump, for example, can save energy expenditures by at least 26% when compared to a new gas boiler.

Power consumption

A ground source heat pump can produce 3 to 4 kW of heat for every 1 kW of electricity it consumes.

How Much is to Install a Heat Pump?

The Energy Saving Trust estimates that installing an air source heat pump will set you back anywhere between £6,000 – £8,000.

The cost of installation also depends on whether you are installing the heat pump as part of a new build or retrofitting it into an existing home.

A 6-8 kW horizontal ground source heat pump system might cost anything from £10,000 to £12,500 to install.

A larger 12kW horizontal ground source heat pump system would set you back around £15,500 to £17,500.

Related: How Long Should A Heat Pump Run Per Day? (SURPRISING!)

Heat pump boiler grant

Don’t forget, you will also be able to apply for the Green Homes Grant Scheme for a voucher towards the cost of installation.

The government is offering up to £5,000 (or £10,000 for low-income households) for energy-saving home improvements.

What Is a Gas Boiler?

A gas boiler is like a big furnace or fire that heats water, which is then sent around your home in pipes to provide heating.

Natural gas is the most common type of fuel used by boilers in the UK as it is relatively cheap and easy to come by.

Other types of fuel that can be used include LPG (liquefied petroleum gas), oil, and electricity.

The lifespan of a gas boiler is now between 10 and 15 years, although many will last much longer if they are properly maintained.

Related: Which Heating System Is Cheapest To Run

Different boiler types

  • Biomass Boilers
  • Combi Boilers
  • Condensing Boilers
  • Electric Boilers
  • Gas (Conventional) Boilers
  • Wood Pellet Boilers

Gas Boiler Running Costs

If you’re connected to mains gas, expect to pay around 4.65p per kilowatt-hour for your energy supply. This implies that if you have a 24 kW boiler, you’ll be spending roughly £1.12 per hour to run it on mains gas.

Since gas boilers are not as efficient as newer models, you may want to consider upgrading your boiler to a newer, more efficient model.

Newer models can be as much as 30% more efficient than older models and could save you £310 a year.

According to the Energy Saving Trust, replacing an old G-rated boiler with a new A-rated condensing boiler could save you £340 and 1,500kg of carbon monoxide a year.

You will also need to service your gas boiler every year to make sure it is running efficiently. This will cost you £60 – £100 on average.

How Much to Install a Gas Boiler?

A combi boiler costs between £1,600 and £3,500 to install, while a heat-only boiler ranges from £1,400 to £2,500. A system boiler may cost anywhere from £1,800 to £2,800.

How Much Space Does a Heat Pump Require vs a Gas Boiler?

Many of us are familiar with the size and scale of gas boilers. They're usually located in an airing cupboard or kitchen and have a flue that runs up the side of your house.

Heat pumps, on the other hand, are a bit more unfamiliar to most of us. The outdoor unit can range in size from that of a small fridge to that of a large chest freezer.

There are two types of outdoor units - air source and ground source.

Air source heat pumps (ASHP) tend to be the more popular choice as they are easier and cheaper to install.

Ground source heat pumps (GSHP) require a bit more work as they need to be buried underground.

An air-source heat pump (ASHP) collects heat from the surrounding environment, whereas a ground source heat pump (GSHP) derives its energy from the earth.

On the outside of your house, an ASHP will usually come in the form of a large box (about 1.2 meters tall by 1 meter wide by about 0.6 meters deep when you allow space for air to flow behind it) with a fan and compressor inside. This box traps heat from the air as it passes through the fan. A 2-meter radius is required in front of the exterior unit.

You'll need room within the house for a hot water cylinder, a control box, and maybe a smaller buffer tank, which is roughly a third of the size of a large hot water cylinder.

A GSHP is connected to your water supply by a pipe that runs across your yard and/or through a borehole. The loop's size is determined by the amount of heat you require and the size of your property.

You'll also need an external unit, which is similar in size to an ASHP, and room within the house for a hot water cylinder, control box, and buffer tank.

For a horizontal loop, between 50m2 and 100m2 of ground per kW is required, whereas, for a borehole loop, around 10 to 20 meters per kW is sufficient.

As a result, for an average 8 kW GSHP, you may need between 400 and 800 m2 of horizontal loop space at a cost of £2,000 to £8,000; between 80 and 160 meters of a borehole will set you back from £7,000 to £20,000.

Related: Where Is My Heat Pump Located? (ALSO IDEAL LOCATIONS)

So What's The Verdict? Heat Pumps or Gas Boiler?

Since the government is banning the installation of gas boilers by 2025 and the fact that you may be eligible for the Green Homes Grant to help with the cost of installing a heat pump, it seems that the writing is on the wall for gas boilers.

Not only are they going to be phased out, but they're also not as efficient as heat pumps, which means you'll be spending more on your energy bills in the long run.

Heat pumps may require a bit more initial investment, but they will save you money in the long run and help reduce your carbon footprint.

Your monthly bills will be a lot cheaper, and you'll be doing your bit to save the planet. So, it's a win-win!

What do you think? Are you planning on switching to a heat pump? Let us know in the comments below!


What is better than a heat pump?

Boilers are more suited to generating quick heat in older, less energy-efficient structures. They may also be incorporated into systems that distribute low-temperature heat in the same way as a heat pump - allowing them to operate alongside underfloor heating.

Can a heat pump replace a gas boiler?

In most cases, yes. You may need a gas boiler if you live in an area with very cold winters and your home isn't connected to the mains gas network.

Related: Everything You Need to Know About Winter Fuel Payments

How long will it take to change my gas boiler for a heat pump?

Depending on which heat pump you have installed, it will take 3-5 days on average to replace your gas boiler for an air source heat pump. Don't forget, if you are having a ground source heat pump installed they will need to bore a hole in your garden which can take a few extra days.

Is it worth getting a heat pump?

Yes, heat pumps are definitely worth it! Not only do they save you money on your energy bills, but they also help to reduce your carbon footprint.

Will my neighbors be disrupted during the installation of a heat pump?

No, your neighbors shouldn't be disrupted during the installation of a heat pump. The exterior unit is usually installed on the side of your house and the hole for the ground source heat pump is usually buried in your garden.
However, the machinery needed to bore the hole for the ground source heat pump can be noisy so your neighbors may hear that. You will also need to have suitable access to your property for the installation team.

How do I know if a heat pump is right for my home?

The first step is to get a Home Energy Survey. This will assess your energy needs and recommend the best solution for your home. You can then compare the costs of different heating systems, including heat pumps, and decide which is right for you.

Will I need to change my radiators if I have a heat pump installed?

No, you can use your existing radiators with a new heat pump. However, because of the low flow temperatures, the amount of heat-emitting surface area required is greater than what is required for boiler-operated heating. This implies that existing radiators may not be suitable. A heat pump engineer will advise whether they should be replaced.

About the Author

Passionate about helping households transition to sustainable energy with helpful information and resources.

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