How Noisy are Heat Pumps?

Article by: Sam Dewey

Introduction

Are Heat Pumps Noisy? You might be surprised to learn that a heat pump is often quieter than a gas boiler. The exact volume of a heat pump will depend on the make and model that you choose, as heat pumps come in a wide range of sizes and varieties.

Heat pumps produce noise while working due to their components. The noise level can sometimes be quite high, and this factor for some people usually affects the decision when buying such systems. However, you’ll find that most modern-day heat pumps are extremely quiet running, with the noise levels rarely causing an issue for homeowners.

It is important to have an overview of how the system works, what the usual noises are and what the government provides for in terms of noise regulation. In this article, we’ll explore the noise levels generated by heat pumps in more detail, including answering the question of exactly how noisy a typical heat pump is in comparison to other household appliances.

How Noisy Is An Air Source Heat Pump?

If you’re thinking about having an air source heat pump installed in your property, you might be wondering exactly how noisy you can expect it to be. Of course, noise isn’t just a concern for your own property, but you also need to be sure that it won’t impact your neighbours or damage your relationship with others living nearby.

You may be surprised to learn that there is a legal limit to how noisy a heat pump can be. The legal noise limit for heat pumps in the UK is 42 decibels. This is measured from the nearest neighbouring property. But just how noisy is 42 decibels in real terms?

42 decibels is the average volume for a refrigerator. So, that low humming that you hear as you walk past your refrigerator? That’s how you can expect your heat pump to sound. This is a similar volume to the whirring of a laptop or computer, which you’d often not even notice.

To help to put the volume of a heat pump into perspective, we’ve compared it to that of other household sounds and appliances in the table below.

Noise	Volume (in decibels)
Breathing	10
Quiet Room	30
Laptop	40
Heat Pump Noise Limit	42
Refrigerator	42
Average Conversation	60
Dishwasher	65
Vacuum Cleaner	85
Hair Dryer	90

As you can see, air source heat pumps are often equivalent in volume to a refrigerator or a laptop, and quieter than the average conversation, a dishwasher, or a vacuum cleaner. Of course, noise levels will vary depending on the make and model of the appliance or heat pump, so it’s always best to check with the manufacturer regarding the noise level of your chosen heat pump to be sure.

The noise generated by a heat pump is often described as white noise. This means that the noise blends into the background rather than being disruptive, meaning that many people won’t even notice the noise that a heat pump creates.

Where Does This Noise Come From?

Air source heat pumps have four main elements when working: a compressor, a condenser, an expansion valve, and an evaporator. Of these elements, the ones making more noise when running are the compressor and the fan. Fan noises depend on different factors: the fan model and its speed, the airflow, and the pressure flow.

The airflow depends on the heat exchanger since air produces an aerodynamic noise when it passes through it. The noise intensity varies according to design and air velocity. Pressure flow, instead, is related indirectly to the noise since an increase in pressure makes the noise decrease and vice versa.

However, noises can derive also from the impact that the gap between ambient air outside the refrigerator with the one where the refrigerating cycle occurs, creates. This causes the water in the air to become denser and freeze in the heat exchanger. In order to guarantee the correct working of the heat pump, it is necessary to run the compressor in reverse for some time in order to eliminate the frost accumulated. This can produce a disturbing noise that may combine with the fan noises.

Are Heat Pumps Noisy For Neighbours?

It’s only natural to be concerned about your neighbours if you are considering having a heat pump installed outside your property. No one wants to cause conflict, so keeping the noise levels down is important to maintain relations with your neighbours. So, how much noise pollution do heat pumps cause, and will it be a concern to your neighbours?

The legal noise limit for a heat pump is 42 decibels. This is measured from the nearest neighbouring property. So, the loudest your heat pump should be at the boundary to your neighbour’s property is 42 decibels. As we have just discovered, this is similar to the noise that a standard refrigerator creates.

Now, consider whether you can hear your refrigerator when you stand outside your property. This is how your neighbour will hear your heat pump when they are inside their home. In fact, even if you’re stood right next to a refrigerator, you’re unlikely to be bothered by the noise.

So, you can rest assured that your heat pump is unlikely to cause any neighbourly disputes as a result of noise pollution. The noisiness of a heat pump is not often a complaint that we hear about!

Can You Make The Heat Pump Quieter?

If you find that your heat pump is generating more noise than usual, we’d always suggest contacting a specialist heat pump engineer to identify the problem. Whilst heat pumps do generate a small amount of noise during operation, this noise shouldn’t be excessive and any changes to the running noise should be investigated in case of any problems.

If your heat pump noise is investigated by an engineer and deemed to be normal, one way to reduce the noise that your heat pump makes is to install dampeners. These can either be placed under the feet of your heat pump unit or onto the bolts that hold the compressor in place. These dampeners will reduce vibration, helping to lower the volume of your heat pump.

Are Heat Pumps Louder In The Winter?

During the winter months, your heat pump will need to work harder. This is because heat in the air is not as readily available when outdoor temperatures are lower. This means that your heat pump will need to work harder to extract heat from the air and to amplify this heat enough to heat your home and your hot water.

When your heat pump works harder, you might notice that the noise it generates is louder. This is because the internal components of your heat pump are under more strain. It’s completely normal for your heat pump to make a bit more noise during the cold winter months. However, if this noise becomes excessive or suddenly changes, it’s best to get your heat pump checked over by a qualified heat pump engineer to check for any potential problems.

Regulations And Government Provisions

In England, the government, in order to promote the use of micro generations and efficient systems, provided for Permitted Development Rights that do not require the installers to provide a planning application and noise impacts assessments. Some limits and regulations in order to control the noise level were also established.

Heat components can produce noise levels of 40 to 50db (decibels). As reported by the UK Government, the noise should not be higher than 42 dB when 1 meter being away from the window of a neighbouring residential property.

The Microgeneration Installer Standard for ASHPs mandates that external fans should be set in a place that would reduce neighbour’s disturbance as much as possible, while the noise of internal ones should be damped by using appropriate tools.

Other regulations concern vibration and the need to place the heat pumps close to bedrooms or in places that produce vibrations, but appropriate materials should be used to reduce such effects, as we have already discussed in this article.

Microgeneration Certification System (MCS) is a way to establish a certification of noise and energy efficiency. The micro wind turbine is the most developed part, and all the new units produced undergo an auditive test in order to be recognised. For these products, some labels are produced, and three colours are used to highlight the potential excess in noise emission (marked in red).

Now, a cooling system isn’t such a necessity in the UK as we don’t often have to deal with extreme weather conditions, but it is quite a nice feature to have at hand just in case. However, the UK’s leading meteorologists have warned that British summers are likely to regularly see temperatures above 40 degrees Celsius (as we saw in 2022) due to global warming issues across the planet.

Our Summary

The good news is that heat pumps are becoming quieter as the technology advances. Whilst the first heat pumps to be manufactured were often noisy during operation, new ways to reduce the volume of heat pumps are continuously being developed, leading to modern heat pumps becoming quieter and quieter.

If you hear people complaining about the volume of heat pumps, it’s likely they’re talking about an older unit which may be 10-15 years old. As technology continues to develop, it’s likely that heat pumps will continue to get quieter, until noise will no longer be a consideration when you’re thinking about installing one of these wonderful heating systems.

If you’re concerned about the noise your heat pump is making, or if you notice any sudden changes to how your heat pump sounds, it’s always best to get it checked over by an experienced heat pump engineer. Get in touch with our team today and we will be able to check for any potential problems, helping to avoid the breakdown of your heat pump and extend it’s lifespan into the future.

Or feel free to contact us and see what bespoke eco heating solution we have in store for you and your property. After all, your green future starts here!