Air Source Heat Pumps and Noise

Are ASHPs noisy and what impact does location and installation make?

If you’re an air source heat pump (ASHP) installer, chances at least one of your customers has asked if their new heat pump is going to be noisy. If you’re not a renewables installer but thinking about becoming one, it’s pretty likely you’ll be asked early on in your sustainable energy career!

Many property owners worry their heat pump will disturb them or their neighbours. But, whilst some heat pumps can be noisy, others are not. It largely depends upon the model you choose to install, and the way it’s installed. But assuming it’s selected and fitted correctly, they’re generally no noisier than an oil boiler.

With that in mind, we’ve set out a few factors to consider before you start an installation, as well as some fixes should you encounter any problems further down the line.

Fully integrated Viessmann all-black solar PV panels.

Viessmann heat pump working in tandem with solar PV.

As is the case with a fossil fuel boiler, the most important factor in reduced noise is that the air source heat pump is specified, fitted and maintained properly so it can work efficiently.

We’ve shared some hints and tips here to help installers but if you want any more information or have any specific enquiries about an air source heat pump installation you’re working on, just contact the Bublshop team.

Here at Bublshop we are experts at air source heat pump installations, and we can help you make sure your air source heat pump install is completed efficiently, effectively… and quietly!

There’s also some advice to help you explain to your customers why their heat pump won’t be any noisier than a fossil fuel boiler.

Don’t forget to call the Bublshop team if you have any questions!

You and your skills

First things first… don’t forget to explain to customers that, as an MCS-certified installer, you can carry out a heat pump installation under permitted development rights (subject to permission from the local planning authority or LPA). If homeowners choose an installer without that qualification, they’d need planning permission (and, of course, their heat pump warranty won’t be valid).

How noisy are ASHPs?

Correctly installed, an air source heat pump will generate around 40-60 decibels (and remember, it will work at the higher end of that range on chilly days when it’s hard at work, and at the bottom end when demand is low). That’s comparable to a conversation or background music, and no louder than the average fridge or any other type of boiler. It’s unlikely your customers will hear their heat pump from inside their house, especially when windows and doors are closed (providing it’s been correctly positioned).

It’s also worth reminding customers that their fossil fuel boiler is probably installed in their kitchen or utility room, whereas the air source heat pump will be outside the property –immediately reducing the noise impact.

Consider the property and its surroundings

Viessmann heat pump and solar PV installation at Maria and Kevin's house in Dorset.

Before you do anything, look carefully at your customer’s home and think about how sound is likely to bounce around the property and where wind might be funnelled. Noise can travel in mysterious ways but think it through and you can choose the most suitable – and the quietest – place to install an air source heat pump.

So, for example, if you were to install a heat pump in a corner location, the sound is likely to be amplified as it will bounce off all available surfaces, and the ASHP will seem noisier.

Then, more specifically, think about where around the property would be most suitable. Try to avoid installing an ASHP outside or below a bedroom window (which is likely to be open more often) and in other locations where people prefer low noise levels (like sitting rooms, for example). On the other hand, fitting a heat pump under a kitchen or bathroom window is generally fine – with fans, water and other appliances running, people are much less likely to notice (or be bothered by) external noise.

Heat pump size and noise calculations

Make sure you do an air source heat pump size calculation before you specify your customer’s heat pump. That way you’ll know exactly what size heat pump is required for the property and its heating and hot water needs.

An air source heat pump modulates depending on the outside temperature, and one that is too small can be noisier. Basically, it has to work harder in colder temperatures to deliver the energy the household requires. The good news is that fewer windows are likely to be open when the heat pump is working hardest (because it’s probably colder outside), so property owners and their neighbours are less likely to notice any noise from an outside energy source (whether an air source heat pump or a fossil fuel boiler).

In summer when windows and doors might be open, ASHPs are generally only used to supply domestic hot water (not heating), which means the heat pump is working less. And when it is working, it’s not working as hard.

Not all heat pumps are equal

Some brands and models of air source heat pumps are designed to operate more quietly, so make sure you check the manufacturer information about noise levels (generally listed in decibels) when selecting the right heat pump for your installation.

Remember new air source heat pumps (R290 models) are quieter than others but they can’t be installed near open windows, doors or cat flaps. If you have to install the heat pump near an opening to the house, R32 models have no window restrictions and would be a good choice.

Chat to the neighbours

It may be polite for your customers to speak to their neighbours about the air source heat pump installation ahead of the install beginning. If appropriate, they may wish you to pop over with them to answer any questions or allay any fears (and help ensure a smooth and hassle-free installation).

Very often any neighbourly concerns can be dealt with in a quick conversation – and the next-door homeowners will feel more confident knowing their needs have been considered in the positioning of the air source heat pump. But remember, if you’re working within permitted development rights, you’re only speaking to them out of courtesy.

Check out acoustic fencing

Don’t forget you can use acoustic fencing around the air source heat pump if there’s enough room. They’re effective at damping down sound, and some people like them from an aesthetic point of view too as they make the heat pump less obvious in a garden. It’s also worth thinking of whether your neighbour can see the heat pump from their property and whether some suitable screening would be beneficial.

Rules and regulations

There are a few rules and regulations to consider when you’re installing an air source heat pump.

An air source heat pump must be at least one metre from the property boundary. They are generally installed close to the house (in part because most homes in the UK don’t have limitless amounts of space) but ASHPs can be installed further away from the house if you’re working at a property with a larger plot. They’re generally effective up to a distance of 15 metres from the house but some heat pumps allow for a great distance.

You can find out lots about rules and regulations on the government website.

Installation is everything

Pay proper attention to how you install an air source heat pump. Poor installation can cause air source heat pumps to make more noise than they otherwise would.

If you’re not familiar with ASHP installation, or you’re fitting a product or brand that’s new to you, make sure you have manufacturer-approved training before you begin the install.

And choose a distributor like Bublshop so you know you’ll have back up and support throughout the install and beyond. We support our installers from start to finish of a heat pump installation, which means if you encounter any challenges with the install, commissioning or maintenance, we’ll be on hand to help out.

Unpack with care

Check the air source heat pump carefully when you unpack it on site and treat it with care while you’re handling and installing it. A damaged heat pump can generate more noise than one that’s in good working order.

Once the ASHP has been installed and commissioned (by an MCS-certified engineer), don’t forget to register the warranty with the manufacturer or distributor (depending on the brand). And remember the heat pump will qualify for a longer warranty if the installer has received manufacturer training.

It’s all about the base

Take time to make sure the ASHP base is level. If it’s installed on an uneven base, the heat pump is likely to get louder over time.

Maintenance is king

Regular maintenance of an air source heat pump will help keep noise levels down by ensuring that all components are functioning correctly, with no loose parts or obstructions.

Customers may need reminding that they should get their air source heat pump serviced annually (in exactly the same way they would a fossil fuel boiler).

Get in touch

We’re here to help and if you have any queries, just get in touch. The team have been working in renewables since 2013, so we know our stuff. All our MCS-certified installers benefit from our comprehensive support service, which includes help with commissioning, as well as a telephone support line, and manufacturer-approved training courses for heating engineers.