Installing an air source heat pump is a worthwhile way to heat your home that could reduce your energy bills as well as your CO₂ emissions.
If you’re thinking about installing an air source heat pump, you’re probably hesitant on a couple of things:
In this simple guide we take you through the air source heat pump installation process and how to get started when deciding if it is the right heating system for your property.
An air source heat pump is a modern, low carbon renewable heating system that extracts heat from the outdoor air, even in temperatures as low as -15°C, and distributes it throughout your home using radiators or underfloor heating.
In a well insulated home, heat pumps deliver the same level of comfort and convenience as a gas boiler- but often at a lower running cost. Because they use electricity to move heat rather than generate it, they can be significantly more efficient, helping you get more heat for your money.
Whatever type of home you live in, whether that’s a flat, terraced house or older home, there’s likely to be a feasible heat pump solution. However different heat pumps are suited to different circumstances, the right system for you will depend on:
For many homeowners an air-source heat pump system will be the best fit, especially if you’re looking to switch from a standard gas boiler and reduce running costs. The unit sits outside your property and is compact enough for most spaces but also cheaper to install than other types of heat pump.
To get the best performance, your home should be well insulated. You may also need larger radiators or underfloor heating, as heat pumps run at lower temperatures than traditional boilers.
If you have a large outdoor space, a ground source heat pump could be an alternative. However these systems are more expensive to install. For smaller properties, such as flats, other options can be more suitable.
Recent changes to planning rules have also made installation easier. The requirement for heat pumps to be installed at least one metre from a neighbouring property has been removed, helping more homes across England to benefit from low-carbon heating.
| Type of heat pump | Best suited property type | Why it suits this type of home |
| Air Source Heat Pump (ASHP) | Most homes (terraced, semi-detached, detached) | Only needs a small outdoor unit and works with existing heating systems, making it suitable for most UK homes without major structural changes. |
Air-to-Water Heat Pump | Homes with radiators or underfloor heating systems | Connects directly to wet heating systems, so it can replace a gas boiler and use existing radiators or underfloor heating. |
| Ground Source Heat Pump (GSHP) | Homes with large gardens or land | Requires underground pipework (trenches or boreholes), so it’s best suited to properties with enough outdoor space for installation. |
| Air-to-Air heat Pump | Flats or homes without wet heating systems | Heats rooms using blown air instead of water, so it works well where installing radiators or pipework isn’t practical. |
So, how much does an air source heat pump cost?
After the government grant, the price of an air source heat pump can vary between £3,999 and over £10,000 depending on numerous factors including:
You can get financial help towards the cost of a heat pump depending on where you live and your circumstances.
If you live in England and Wales, you can get £7,500 towards an air source heat pump via the boiler upgrade scheme but also.
If you live in Scotland, Home Energy Scotland offers grants of up to £7,500 towards an air source heat pump. This can increase to £9,000 for people in remote areas who qualify for rural uplift. You can also apply for an interest-free loan of up to £7,500 to cover the remaining costs. For more details, check out the Scottish Government Urban Rural Classification.
Choosing the right installer is a crucial step in your heat pump journey. It’s important to work with a certified professional who has experience designing and installing air source heat pump systems to UK standards.
Look for an installer accredited by MCS (Microgeneration Certification Scheme)– a UK Government-backed quality assurance scheme, that certifies renewable products and installers. This ensures your system is installed to recognised industry standards and is also required to access support such as the Boiler Upgrade Scheme. Cahill Renewables is MCS-certified, giving you confidence that installations meet these quality benchmarks.
A qualified installer will carry out a detailed assessment of your home to determine the most suitable system.This includes calculating your property’s heat demand, assessing insulation levels, and reviewing your existing heating setup.
Based on this assessment, they’ll recommend the right heat pump for your needs and highlight any upgrades required to ensure the system performs efficiently. This often includes installing larger radiators or, in some cases, suggesting improvements to insulation.You should expect a clear, tailored quote that outlines the system design, installation work, and any additional upgrades needed.
Once you’ve got the quotes for the type of heat pump to be installed, take time to compare them carefully.
Each installation quote will likely have different recommendations compared to the others. If you’re eligible for funding, make sure you understand if this has been accounted for- if you’re located in England or Wales, your installer should also apply for the boiler upgrade scheme for you and should deduct this from their price.
Keep in mind: the cheapest option is perhaps not the best option for you.
Make sure you are comparing quotes that contain all the necessary works, such as:
An air source heat pump installation usually takes 2-5 days to complete (this can change depending on the type of heat pump you choose to install). During this time, your heating system will be turned off for most of the installation.
If your heat pump is being installed in winter, your installer might provide temporary electric heaters to keep your home warm while the system is being fitted.
Insulation before heat pump installation
If you’re planning to improve your home insulation, it’s best to complete this before your heat pump installation. This helps your heat pump system work efficiently from day one.
Heat pumps can work in most homes, but they perform more efficiently in well-insulated properties.
Improving the insulation of your property makes your home more comfortable and reduces your heating costs by:
Heat pump unit
This installation process is based on a standard air source heat pump.
The installer will install the heat pump unit outside of your home. These external units vary in size but can be as much as 1 metre x 2 metres. That’s around the same space as two wheelie bins. While the external unit must always be placed outdoors as it draws in air to generate energy, the indoor components, such as the cylinder and controls, can be placed in spaces like garages, airing cupboards or even spare rooms.
If the existing ground surface isn’t suitable, a platform might need to be installed for the unit. Your installer will also ensure adequate drainage is in place to manage any condensation produced.
Hot water cylinder
Air source heat pumps don’t always provide hot water in the same way as a combi boiler, so you may need another way to supply hot water depending on your system.
Usually, your installer will fit a hot water cylinder to store water that’s been heated by the heat pump, ready for when you need it (for example, for showers and taps etc). If you already have a hot water cylinder, it will potentially need to be replaced with one that’s suitable for use with a heat pump.
If your heat pump doesn’t provide hot water directly, your installer can suggest alternative options available to you. These include:
Radiators
Heat pumps typically send hot water to radiators at a lower temperature than an equivalent fossil fuel central heating system, often between 35-45°C. But you can still heat your home effectively by:
Larger radiators have a greater surface area, therefore they emit more heat into the room even at lower temperatures. This doesn’t necessarily mean you need to give up more wall space, though:
Plumbing & Wiring
The installer will connect the air source heat pump and hot water cylinder to your existing heating and hot water system. They’ll also replace any pipework that needs to be upgraded and flush out existing systems to remove any built-up debris.
The heat pump will also need to be connected to your electricity supply. Many installers will bring in a qualified electrician for this, who will also connect and set up the controls.
Once everything is in place, connected and ready. The installer will start commissioning, this involves turning the air source heat pump system on to check that everything is functioning as it should be. They’ll check for leaks, air bleeding out of the system and making sure radiators are balanced appropriately.
Once everything is working as it should, your installer should take the time to make sure you understand:
You’ll also be given warranty information, clear instructions and documentation to make sure you’re set up and ready to go. Keep their contact details in your phone just in case you think of any urgent questions down the line.
Have you got any other gas appliances?
If your previous heating system was your only gas appliance, you’ll be able to have your gas supply disconnected. Therefore, you won’t have to pay a gas standing charge. You can contact your energy supplier to arrange this or ask your installer if they can organise it for you. There may be a charge for this.
Your installer will provide you with contact details for any issues that could arise, as well as information on arranging your first service.
It’s recommended to service your heat pump annually, like you would for other heating systems such as a boiler, regular servicing helps keep it running efficiently and can prevent potential issues. A typical service usually includes:
Keep an eye on how your heat pump performs, particularly during colder weather. Knowing what’s ‘normal’ for your system means you’ll be able to spot any changes early. If problems do arise, contact your installer to arrange a visit.
Due to increasing demand, the time it takes to get a heat pump installed can vary and in some cases you’ll need to wait several months for an available installation slot. If you’re considering an air source heat pump, it’s a good idea to start the process sooner rather than later.
The installation itself typically takes around three to five days, however time scales can be longer depending on the work involved.
It can take longer if:
Your installer will be able to give you a more accurate timeframe once they’ve assessed your property.
If you move into a property that has a heat pump installed, it’s important to understand how the system works so you can use it effectively.
You should:
If you’re unsure about anything, consider contacting a qualified installer to inspect the system and make sure it’s set up correctly.
Heat pumps work differently from traditional boilers, so using them correctly can make a big difference to comfort and efficiency.
To get the best performance from your system:
Heat pumps are designed to maintain a stable temperature rather than heat a home rapidly. Once you understand how your system works, you can run it more efficiently and keep your energy use under control.
Installing a heat pump can cause some disruption to your daily routine, but this depends on your home and the work required.
Typical installation work usually include:
In some cases, additional upgrades like underfloor heating may be recommended, although this isn’t always necessary and can involve more extensive work.
Whilst there can be some disruption, it’s usually possible to remain in your home during installation. However, if the work is likely to significantly affect your daily routine, you may want to consider making arrangements to be away from home while it takes place.
Cahill Renewables is an MCS-certified installer and Which? Trusted Trader. All installations are subject to eligibility, property suitability and a full technical assessment. Any grants or funding mentioned are subject to availability, eligibility criteria and terms & conditions.
Hear from current home owners and their experience with Cahill Renewables here →
