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This guide was last updated: April 2024
A heat pump is a device that extracts heat from the air or ground, which it then processes to heat or cool your home. Because it typically uses less energy than a conventional heating system, a heat pump can be an effective way to heat your home while reducing your home’s environmental impact.
In this guide, we cover:
- How do heat pumps work?
- What are the benefits of installing a heat pump in your home?
- What types of heat pumps are there?
- How much do heat pumps cost?
- How efficient are heat pumps?
- Are there any grants or incentives for heat pumps?
- How are heat pumps installed and maintained?
- Heat pump FAQs
How do heat pumps work?
A heat pump works by moving heat from one place to another, instead of generating heat like a traditional gas boiler.
It does this by using a refrigerant to absorb heat from the air or ground outside your home and then compressing it to a higher temperature before distributing it inside your home to provide heating.
The process can be reversed to provide cooling by absorbing heat from inside your home and releasing it outside.
It's similar to how a fridge works. But instead of cooling down a small space, it warms up a larger space. Like a fridge, it has a compressor, evaporator and condenser. The compressor pressurizes the refrigerant, which causes it to heat up. The hot refrigerant then goes to the condenser, where it releases the heat, which warms up the air inside your home.
You can think of it as a machine that moves heat from one place to another, instead of making heat. This makes it much more energy efficient than traditional central heating systems.
What are the benefits of installing a heat pump in your home?
There are lots of benefits to installing a heat pump in your home.
Energy efficiency
Heat pumps are highly energy efficient as they use less energy to produce the same amount of heat as traditional heating systems. That doesn’t mean it’s guaranteed to save you money, however (see the ‘Cost-effective’ section, below).
Environmental benefits
Because heat pumps don’t burn fossil fuels, they don’t produce emissions that contribute to air pollution. They can also be powered by renewable energy sources, such as solar or wind power, making them a clean and renewable heating and cooling option.
Comfort
Heat pumps can provide both heating and cooling, making them a convenient and flexible option for controlling the temperature in your home.
Durability
Heat pumps are durable and should continue to operate for up to 25 years. They should require less maintenance and have lower long-term costs than traditional HVAC systems.
Quiet operation
Most modern heat pumps are designed to run quietly, so they shouldn’t disrupt the comfort of your home with a loud noise.
Cost-effective
Heat pumps can be cost-effective in both the short and long term. But this isn’t always the case.
When the gap between electricity and gas prices is small, a heat pump has more chance of being cheaper to run than a gas boiler thanks to its high efficiency. But when the gap is larger, it may be more expensive to run than a gas boiler.
Any savings will be dependent on the type of heat pump, the amount of insulation your home has, the comparable cost of electricity and gas, and other factors.
What types of heat pumps are there?
Heat pumps are generally categorised as either ‘ground source’ or ‘air source’. But there are actually three main types of heat pumps: ground source, air to air, and air to water.
When considering the type of heat pump you might like to install, bear in mind that the cost and efficiency of each type of heat pump can vary depending on the size of the system, the climate where you are and how well your home’s insulated, amongst other things.
Speak with a professional installer to get an estimate of the cost and efficiency of each type of heat pump for your specific case.
Ground source heat pumps
These use pipes buried underground (usually in your back garden) to absorb heat from the earth and bring it inside to heat your home.
Since ground source heat pumps produce a lower-temperature heat, it’s less efficient at heating traditional radiators and is better suited to underfloor heating.
Ground source heat pumps tend to be more expensive to install than other types of heat pumps due to the cost of installing the ground loop which sits below your garden. But they also tend to have lower running costs and higher efficiency levels, which can make them more cost-effective in the long term.
Air-to-air heat pumps
These absorb the heat in the outside air and bring it inside to heat your home using fans. They can’t be used to heat water.
Air-to-air heat pumps are a good option if you’re looking for a cost-effective and easy-to-install solution. They’re less efficient than ground source heat pumps, but they’re also less expensive and can be installed in homes with limited space.
Air-to-water heat pumps
These also absorb the heat in the outside air, but they transfer it to a water-based heating system to heat your home.
Air-to-water heat pumps are a good option if you want to use renewable energy and reduce your carbon footprint due to their efficiency. They’re also a good option if you want to use hot water for space heating and domestic hot water. They’re more efficient than air-to-air heat pumps but less efficient than ground-source heat pumps.
Hybrid heat pumps
Also called a dual energy system, hybrid pumps aren’t really hybrid pumps at all… they’re regular ground or air source heat pumps that are integrated with a traditional gas boiler.
Hybrid systems automatically switch between using either the pump or gas boiler, depending on which is more efficient at the time. This is influenced by the temperature and weather conditions.
How much do heat pumps cost?
You can expect to pay between £8,000 and £35,000 for a heat pump. But this can be reduced to as little as £500 with a grant (see our grants guide for more information).1 You’ll also need to pay for an installer to fit it to your home.
The price of a heat pump will vary depending on:
- the type of heat pump
- the size
- the make and model
Air source heat pumps and cheaper to buy and install than ground source heat pumps since they don’t require a ground loop.
You can buy heat pumps in different sizes. Smaller 5kWh pumps will be much cheaper than larger 16kWh heat pumps, for example.
Like all products, the make and model affect the price. Top-end brands and models will cost more than other brands and models.
How efficient are heat pumps?
Heat pumps are highly efficient as they use less energy to produce the same amount of heat as traditional heating systems.
The efficiency of a heat pump is measured by its coefficient of performance (COP). This represents the ratio of the heat output to the energy input. If it takes 1kWh to power a heat pump that generates 3kWh of heat, the COP is 3. The higher the COP, the more efficient the heat pump is.
Each type of heat pump has a different COP:
- Ground source heat pumps have a COP of 3-5
- Air-to-air heat pumps have a COP of 2-3
- Air-to-water heat pumps have a COP of 2-4
To put this into perspective, the COP of a gas boiler is around 0.93. That’s because a small amount of energy is lost in the process of extracting energy by burning the gas it receives through the pipes.
The efficiency of a heat pump can also be affected by:
- its location
- the climate where you are
- how well your home’s insulated
- the size of your home
- the specific make and model
A heat pump will perform effectively at even minus temperatures. But it will operate more efficiently in warmer temperatures.
Are there any grants or incentives for heat pumps?
There are several ways you could get financial help to fund the cost of a heat pump.
You could apply for a grant, which is money you don’t have to pay back. Or you could take out a loan, which may or may not charge interest, depending on the scheme.
The following grants and incentives are correct as of April 2024.
England and Wales
The Boiler Upgrade Scheme is a government grant that can save you up to £7,500 on the cost of replacing an oil, gas or electric heating system with a heat pump. Applications grew by nearly 40% since the grant was increased from £6,000 in 2023.2
Scotland
The Home Energy Scotland Grant and Loan scheme consists of a grant of up to £9,000 and an interest-free loan of up to £7,500.
Northern Ireland
There are currently no grants or incentives for heat pumps in Northern Ireland.
How are heat pumps installed and maintained?
Heat pumps are typically installed by professional installers who are trained and certified to install and maintain heat pumps. You’ll need a Microgeneration Certification Scheme (MCS) certified installer if you’re applying for funding from the Boiler Upgrade Scheme.
You can find a qualified installer for free using the Snugg platform. Sign up and explore your options.
The installation process will vary depending on the type of heat pump and the specific requirements of your home.
Ground source heat pumps
Installing a ground source heat pump can be an efficient and sustainable way to heat your home. But it’s a relatively complex process that requires the expertise of a qualified professional.
- Hiring a qualified professional: Electrical connections will need to be made, and plumbing circuits will need to be installed. So make sure you find an MCS-accredited installer who has experience installing ground source heat pumps.
- Site assessment: The soil composition and underground water and rock strata of your home will need to be assessed. This will determine the size and type of heat exchanger needed.
- System design: To ensure the ground source heat pump is specified and built correctly, the installer will design a system taking into account various aspects of your home, including its size, how well insulated it is, the existing heating system it has installed, the weather where you are, and the settings of the chosen heat pump’s controls.
- Installing the ground loop: Depending on the size of your garden, either a horizontal or vertical ground loop will be installed. A horizontal loop is long, sits around six feet below your garden, and would and would need to be installed by a digger. A vertical ground loop can be used where space is limited, and would be installed using a borehole dug by a large drill.
- Installing the indoor units: The indoor units include a large compressor and condenser. They’ll need to be installed in a suitable location, such as a utility room or basement. Once installed, they’ll be connected to the ground loop and the existing heating system.
- Commissioning: After the installation, the system will be turned on and tested to make sure that it runs at maximum efficiency. This will include setting the correct flow and return temperatures, optimising the controls, and testing for leaks.
- Maintenance: Ground source heat pumps need regular maintenance to make sure they continue to operate at maximum efficiency. This includes cleaning the filters, inspecting the ground loop, and checking the refrigerant levels.
A ground source heat pump will typically take around a week to install.
Air-source heat pumps
Air-source heat pumps are simpler to install than ground-source heat pumps. But you’ll still need a qualified installer to complete the installation for you.
- Hiring a qualified professional: Electrical connections will need to be made, and ductwork will need to be installed. So make sure you find an MCS-accredited installer who has experience installing air-source heat pumps.
- Site assessment: The installer will assess the size and layout of your home, as well as the insulation levels and existing heating system, to determine the size and type of heat pump needed.
- System design: To ensure the air-source heat pump is specified and built correctly, the installer will design a system taking into account various aspects of your home, including its size, how well insulated it is, the existing heating system it has installed, the weather where you are, and the settings of the chosen heat pump’s controls.
- Installing the ductwork (air-to-air heat pumps): The ductwork will be installed to distribute the heated or cooled air throughout your home. The installer will determine the best location for the outdoor and indoor units, and will connect them via the ductwork.
- Installing the radiators (air-to-water heat pumps): The pump will be connected to an existing or new hot water cylinder, which pumps heat around your home through under-floor or oversized radiators which will need to be installed if you don’t already have them.
- Commissioning: After the installation, the system will be turned on and tested to make sure that it runs at maximum efficiency. This will include setting the correct airflow and temperature settings (air-to-air) or flow and return temperatures (air-to-water), optimising the controls, and testing for leaks.
- Maintenance: Air-source heat pumps need regular maintenance to make sure they continue to operate at maximum efficiency. This might include cleaning the filters, inspecting the water loop, or checking the refrigerant levels, depending on whether you have and air-to-air or air-to-water heat pump installed.
An air-source heat pump will typically take one to five days to install.
Heat Pumps FAQs
Heat pumps may have started to gain popularity in the UK only recently, but they’re already a significant part of the energy infrastructure in many parts of the world. As a result, there are lots of manufacturers of heat pumps.
Brands that sell heat pumps in the UK include:
- Ecoforest
- Kensa
- LG
- Mitsubishi
- Nibe
- Panasonic
- Samsung
- Stiebel-Eltron
- Vaillant
- Viessmann
- Worcester-Bosch
These brands offer a variety of heat pump models and types, including ground-source heat pumps, air-to-air heat pumps, and air-to-water heat pumps.
The size of heat pump you need will depend on several factors, including:
- The size of your home: The larger the home, the larger the heat pump will need to be to meet the heating demand.
- Insulation levels: A well-insulated home will need a smaller heat pump than a poorly insulated home.
- Size of household: A home with more people living in it will need a larger heat pump to meet the heating demand.
- Climate: The climate where you live will also play a role in determining the size of the heat pump you’ll need. In colder climates, a larger heat pump will be needed to keep the home warm.
- Type of heat pump: Different types of heat pumps have different efficiencies. Some are better at handling extreme temperatures.
A qualified professional, such as an MCS-accredited installer, will be able to determine the size of the heat pump you need by conducting a heat load calculation. This calculation takes into account all of the factors mentioned above and is used to determine the heating demand of your home.
Just one heat pump should be able to supply enough heat to keep almost any home warm. Heat pumps come in different sizes, so you’ll simply need one suitably sized heat pump for your home rather than several.
A heat pump has the potential to save you money in the long term as they’re more energy efficient than traditional heating systems.
However, this will depend on various factors, including the cost of electricity in relation to gas - the smaller the difference, the more cost-effective a heat pump will be in comparison to a gas boiler due to its increased energy-to-heat efficiency.
Other things to factor in are your energy usage, the size and efficiency of the heat pump, and the costs of installation and any upgrades (e.g. hot water tank, piping and radiators).
And although not a saving, it’s worth bearing in mind that a heat pump can add value to your home as well as being better for the environment.
As of March 2024, heat pumps could save an average household with a gas boiler around £234 per year.3
Yes. Heat pumps can work in cold weather, even down to -20 Celsius! But their efficiency may decrease as the temperature drops.
The lifespan of a heat pump will vary depending on the type and brand. The average heat pump should be able to last for around 15-20 years.
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