How loud is heat pump noise?

How loud is heat pump noise?

Answer: Heat pumps shouldn’t be excessively noisy. A healthy ground source heat pump will be approx 42 decibels (dB); much less noisy than a boiler. An air source heat pump can be between 40 – 60 dB, although between 50 – 60 dB might indicate maintenance issues.

 

More Details: Noise levels of ASHPs and GSHPs

You have many considerations when installing greener heating in your home, and for heat pumps, noise is one of them. Whether you are looking to install a Ground Source Heat Pump (GSHP) or an Air Source Heat Pump (ASHP), the level of decibels is important for everyone, including your neighbours.

In this article, we will look at the noise levels of heat pumps. We will cover GSHPs and ASHPs, and provide some comparisons. The guide will wrap up each section with advice on how to minimise the noise of your heat pump.

If you’re considering installing a heat pump in your home, try our free calculator to work out your savings and earning from the government’s Domestic RHI scheme.

 

Ground Source Heat Pumps

A GSHP is a heat pump system which sources heat from under soil or water. The temperature is relatively consistent deep down, no matter the weather. This provides an excellent source of heat for the modern home. Government incentives help make ground source heat pumps even more appealing, and you can read about the RHI scheme here.

 

GSHP noise levels

A ground source heat pump produces some noise due to the components within it, but this is negligible in almost every case. In truth, GSHPs are always quieter than ASHPs.

This is due to the fact that they have no requirement for a fan or condensing unit. Furthermore, GSHPs have a lower compressor power capacity, due to the fact that extraction of heat from the ground is more consistent. The temperature is warmer down there, and this means the heat pump doesn’t need to work quite so hard to heat your home and/or hot water.

A GSHP has a maximum estimated decibel level of 42 dB, and that’s if you’re standing a metre away. This can be compared to a fridge in any normal home. In addition, there is less need to worry about the neighbours because the system is largely contained within your walls – often in a garage, a shed, or in with your utilities or basement.

Overall, it can be confidently stated that if installed correctly, a ground source heat pump is less noisy than a traditional gas or oil boiler.

There have been cases whereby noise travels up pipes, but this is very uncommon and your installer will be aware of the potential for this in older homes. Other homeowners have complained that their system wasn’t set up with noise-absorbing pads, but again, best practice dictates that a good installer will spot this. These problems are unlikely to occur with your own installation, but it’s always good to bring up the topic when speaking to a contractor.

So, in a nutshell, there are no real noise considerations when installing a ground source heat pump. As the heat pump technology continues to improve in the coming years, this will become a complete non-issue for every homeowner.

 

How to prevent GSHP noise

If your GSHP is noisy, it’s not functioning as it should. Luckily, there are plenty of experts that can help with your heat pump repair, but here are some ways to avoid this expense.

Thorough survey:
Your installation partner must conduct a thorough survey of your property to determine which technology suits, and how best to install it. This is a natural prerequisite to heat pump projects.

Correct installation:
Don’t risk problems by botching the installation from the start. Your installer should be accredited and registered with all the correct schemes. You can find a list of what to check with your heat pump installer here.

Follow guidelines:
Follow the advice of your installer about the operation of your heat pump. In most cases, this will be simple. It may have different modes that are applicable to different seasons.

Maintenance:
Maintain your GSHP properly to avoid the breakdown of its components. This excellent YouGen article provides advice about servicing your ground source heat pump. The guide mentions the servicing of the compressor (which is non-maintainable), water pumps, electronics, external pipes, ground arrays, antifreeze, and heating fluid. A yearly check-up is recommended.

 

Other considerations

Installing a ground source heat pump is a bigger project than installing an air source heat pump. Not all properties are suited to a GSHP, primarily due to the need for outdoor space. A borehole will require less space (as it goes straight down into the ground) but more common are trenches for the GSHP loops; this requires more space. A borehole will be more expensive. You don’t typically need planning permission for ground source heat pumps, but check with your local authority to be sure, as some protected buildings might be more regulated.

Also read: Ground Source Heat Pump Installation Costs

 

Air Source Heat Pumps

An air source heat pump (ASHP) is a heating system which extracts heat from the outside air. The system absorbs heat into a fluid, which is then passed through a compressor to increase its temperature. This heat is then utilised to power your property’s radiators, hot water, or underfloor heating. ASHPs work in all conditions, not just when the climate is warm and dry. These systems are proven to work at temperatures as low as -15 C.

You can get air-to-water heat pumps, and air-to-air heat pumps. The former utilises a wet central heating system (most common in the UK and Europe), and the latter creates warm air which is distributed in your home via fans. Air-to-air heat pumps don’t usually couple themselves with the ability to heat hot water. We usually deal with air-to-water systems.

Homeowners with ASHPs benefit from the same government incentive schemes as those who use GSHPs. Contact us for more information about how you can save cash with this system, or try our free calculator for an idea on numbers.

 

ASHP noise levels

Now, this is a more contentious issue than with ground source heat pumps. Air source heat pumps have developed a reputation for being noisy, with high-profile cases of neighbour conflicts. Indeed, this issue is the reason for our guide to heat pump noise levels.

It must be stated that these cases are in the minority. Air source heat pumps wouldn’t have become so popular if they were an inherent nuisance to every homeowner. Don’t be put-off by the scare stories! However, let’s look into the issue of ASHP noise.

There are four main components in an ASHP that cause noise: the compressor, the AC condenser, the evaporator, and the expansion valve. However, it is the fan that often causes most worries. In addition to the compressor, the fan is typically the element that raises the decibels to a concerning level for the homeowner.

The level of fan noise depends on the manufacturer and model, together with the airflow and pressure. A ground source heat pump has no fan, which is why noise concerns are a less popular topic for that particular technology.

 

The details of ASHP noise

Depending on the system manufacturer, you can expect noise of between 40 – 60 decibels (dB) from an air source heat pump. This measurement is based on a one-metre distance, and of course reduces the further away you get from the system. 60 decibels is very uncommon, but can be compared to the noise level of a regular conversation, or background music. 40 decibels can be compared to a bird call, or the ambient sound in a library.

It’s not only the components that create noise, but the vibrations that are created by the system exchanges. There will be inevitable noise from the air interacting with the heat exchanger, but this depends on the pressure levels at any given time. The motor, as a moving part, will also give-off some noise, although this is minimal if it’s maintained properly.

Depending on the heating requirements for your property, the fan might be required to work harder and thus runs at a higher speed. In general, smaller ASHP fans operate at a lower speed, whilst the bigger systems are quicker. Modern heat pumps systems alter their speed according to the conditions, to maximise efficiency.

Planning standards assume that background noise is consistently under 40 dB. According to SW Energy, compliance with planning laws mean that an ASHP should be under 42 dB from an assessment position equidistant to the space between the system and a neighbouring property.

In general, a UK council will take action against a noise which is +10 dB above normal background noise in the area. An increase of +5 dB isn’t usually a problem, but much higher will be a likely source of complaints.

Consider that the expected noise level is 40 – 60 dB (more likely 40 – 50 dB in truth) from a metre distance away. This drops dramatically as you get further away. It’s very unlikely that your property (or at least the ASHP installation location) is 1m from a neighbour. This would be poor installation procedure, and not recommended by any decent installer. Therefore, it’s very unlikely that the noise levels will be disturbing to anybody.

 

The takeaway argument..

In a nutshell, you can expect a regular “hum” from an ASHP, due to the movement of the air and the components within the system. However, if an air source heat pump is installed in the correct position at a suitable property, it is highly unlikely to cause concern.

All being well, there is no reason to avoid an air source heat pump due to noise. As the technology continues to improve, these systems will get even quieter.

 

How to prevent ASHP noise

There are a few ways to limit ASHP noise. Here’s our list of tips for homeowners.

System location:
If a tree fell in the woods, would it make any noise? Of course it would! Try to situate your heat pump system away from bedroom windows (yours and your neighbour). Whilst this approach won’t limit the noise itself, it does limit the impact of any noise.

Keep it clear:
An air source heat pump must have a clear area in order to displace air without obstacles. The system must be installed without direct (or close) contact to nearby walls, fences, or hedges.

Double-glazing:
Again, this is about minimising the impact. Every modern home will have double (or triple) glazed windows and doors. In fact, this is a requirement for meeting efficiency standards, which in turn allows you to qualify for the RHI payments on green heating solutions. Glazing will minimise the noise entering your home from the ASHP system.

Select a good manufacturer:
You get what you pay for. The government’s financial incentives (RHI) are there to make installation and operation easier and more affordable for homeowners. Furthermore, there are lots of financing options which cover the initial outlay. There’s no need to take a risk with poor technology, as the best systems are available at affordable rates.

Enclose your heat pump:
Specialist contractors offer heat pump enclosures which are specifically designed to minimise the noise. These are purpose-built containers with side panels and sound-dampening paint. They can be cladded to fit in with the surroundings, and are totally weatherproof.

Run the compressor in reverse:
Your ASHP can also get noisy due to the difference in temperature between the air outside and the air in the refrigerating cycle. Air can become denser, and potentially freeze inside the heat exchanger, which increases the friction and noise from the system. Sometimes you may need to operate the compressor in reverse to get rid of the frost.

As per GSHP advice (see above):
The advice for ground source heat pump noise still stands for ASHPs. Use a reputable installer, ensure that a comprehensive survey is done in advance, and maintain your system properly. ASHP noise can increase in colder months if frost is allowed to gather within the heat exchanger. An annual system check-up will ensure that your heat pump system is in good working order, and noise is kept to a minimum.

 

Further reading

We’ve produced a number of other blog article guides that will be useful for homeowners keen to switch to renewable heating systems. Here’s an overview of what to expect.

A guide to air source heat pump running costs:
This article looks at how much you can expect to pay for the operation of an air source heat pump in your home. We take into account your

Air source heat pump funding & financing:
We know that the initial outlay can be demanding on homeowners, even if the eventual savings are huge. Luckily, there are lots of funding and financing options available in the UK. This article outlines our partnership with an installer that has an innovative way to financing your project.

What is the renewable heat incentive (RHI)? A guide:
In this article, we outline the details and qualification requirements for the domestic and non-domestic RHI scheme in Britain. For those who want to switch to renewable heating in their home, this is important reading.

External link:

If you’d like to dig further into the topic of heat pump noise (particularly ASHPs), this government report [downloadable PDF] is essential reading.