How do I talk about air source heat pumps (ASHPs) with my customers?
When speaking to customers looking at getting an air source heat pump installed at their property, you’ll likely have to answer some in-depth questions.
Read on to learn how you can help your customer decide if an air source heat pump is right for them and their home, with straightforward answers to some of those tricky questions.
Is the property suitable for an air source heat pump in the first place?
Air source heat pumps can be fitted at most property types. Changes to certain regulations have also made it easier to have an ASHP installed under permitted development rules. There are, however, some important considerations that installers and homeowners should both be aware of:
Sound levels
As of May 2025, the noise from an air source heat pump cannot exceed 37 decibels (dBA) when measured from the closest habitable room of a neighbour’s property. This is in accordance with the MCS 020 sound limit.
The level of sound that is recorded depends on several individual factors. Sound can ‘bounce’ off walls and appear to be greater when the unit is positioned in a certain way. At Baxi, our heat pumps are designed to be very quiet and placed at almost any location on the property, making air source heat pumps an accessible option for most homes.
Is there enough outdoor space?
The air source heat pump will need to have enough outdoor space to draw in enough ambient air to operate effectively. Updated regulations in 2025 have removed the need for the heat pump to be at least one metre from the property boundary, as had previously been the case, meaning that in essence, it is possible for a heat pump to be positioned anywhere within the perimeter of the garden.
That said, it’s important that there are no obstructions in front of the heat pump, including anything being propped against it, like bicycles or garden furniture. Noise, again, will also need to be a consideration. It’s important that the installation recommendations from the installation manual are followed closely.
A stable surface
The heat pump will need to be situated on a flat, stable surface, ideally at the back or at the side of the property. This allows for suitable air flow, with the surface itself being able to support the eight of the unit without transmitting noise or vibration into the house.
It’s also advisable to have gravel underneath the heat pump for condensate to safely dissipate into to reduce the risk of a slippery floor.
How do ASHPs work?
ASHPs work by extracting heat present in the air, ground or water and boosts it so it can be used for heat and hot water in buildings.
Ambient air is pulled across a finned heat exchanger and the refrigerant inside is then superheated via an electrically driven compressor (we promise this is as technical as we’ll get!). This heat is then transferred to water through a plate heat exchanger and pumped throughout the building to radiators, underfloor heating or hot water tanks – just like a boiler.
The process still works if the weather is cold because there is always some heat energy in the outside air for the refrigerant to absorb. Our ASHPs can actually work in temperatures as low as -25 °C. This is something you might want to share with your customers if they have concerns about heating during the colder months.
In Winter, a defrost cycle is activated by sensors within the unit. This essentially puts the heat pump into reverse, warming the outside unit sufficiently enough to melt away frost or ice that may have built up. The process usually only takes a few minutes, with minimal disruption.
To help keep the heat pump working effectively, it’s important that any debris is cleared from in front of the unit. During the defrost cycle, it’s normal for white steam to be visible – this is completely normal and is a natural part of the process. In fact, seeing steam shows that the heat pump is doing exactly what it needs to.
Since the heat energy comes from the air and is not generated by gas or electricity, with a good installation, ASHPs can run at up to 530% efficiency. This means that for every kilowatt of energy created by a boiler, 5.3kW is created by an ASHP.
How much does an air source heat pump cost?
The biggest barriers to uptake of heat pumps tend to be cost related. This is down to the installation which, combined with the system itself, could cost the homeowner between £8,000 and £15,000. This price is often seen as too high, especially when considered alongside high electricity prices due to environmental taxes and levies.
Thankfully, government funding is available in the shape of the Boiler Upgrade Scheme (BUS) for households in England and Wales, which offers a grant of £7,500 towards the installation cost of a heat pump.
For homeowners in Scotland, the Home Energy Scotland Grant and Loan offers interest-free loans and grants for energy efficiency improvements, including heat pumps.
Be sure to make your customers aware of the relevant schemes and loans available to them for greener household upgrades.
How efficient are heat pumps?
The reality is the majority of homes can be suitable for an air source heat pump, but the cost-effectiveness of the installation and its ongoing performance will depend on a number of factors. As a rule, a heat pump can be an effective and efficient heating source when paired with good levels of insulation, correct commissioning, regular servicing and proper use by the homeowner. These are all things you can remind your customers about during regular servicing throughout the year.
Right from the start of the process, though, correct sizing is essential. As with any heating appliance, oversizing a heat pump will increase running costs and lower system efficiency. When a heat pump is oversized, it will ‘short cycle’, which means it fluctuates between being on and off. This ultimately makes the appliance much less efficient as well as risking damage to the compressor.
As a low-temperature heating source, a heat pump is at its best when it runs constantly rather in the shorter bursts homeowners are used to seeing from their boiler. This provides a constant warmth in the home, rather than temperatures which fluctuate from hot to cold. A full, room-by-room heat loss calculation will ensure the pump can be correctly sized, while also identifying whether any upgrades to the fabric of the property will boost its efficiency.
Can a heat pump work with existing radiators or heating systems?
As air source heat pumps work at lower temperatures than boilers, there may be a requirement for radiators to be modified, though this isn’t always the case. Underfloor heating systems, however, work well with heat pumps.
A heat loss calculation is key in working out whether radiators need to be upsized. In most cases, one or two radiators might need to be changed.
Choosing Baxi for air source heat pump installations
At Baxi, we’re committed to making air source heat pump installations smooth and straightforward through our range of air source heat pump installer courses. These are designed to provide you with all the information you need to help your customer make the right choice for their needs. From understanding how air source heat pumps work to designing, installing and commissioning them, there’s a course for wherever you are on your journey.
Click here to find the right course for you.
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