Heat pumps are a great addition to many homes and commercial buildings, but some people may have reservations about them and the levels of noise they create. The good news is that most air source heat pumps are actually quieter than the average gas boiler, and when sited in the right place and installed correctly, shouldn’t really cause any disturbance at all.
The noise created by a heat pump will in part depend on how hard it is having to work at the time, but factors, including the make, model and size, will all have a bearing on how loud the heat pump is during operation. Here, we’ll give you some insight into air source heat pumps and their noise levels, and compare them with other appliances.
Legal Limits with Air Source Heat Pump noise levels
There are actually legal limits when it comes to the allowed level of noise with air source heat pumps. The legal noise limit for heat pumps is 42 decibels — and this value is measured within one metre of the nearest neighbouring property — but how loud in reality is this?
To compare with other appliance noises in a household, 42 decibels is approximately the same noise level as a refrigerator, so it really will just be a low constant hum sound that you will be unlikely to really notice.
To put the noise level in some sort of perspective, here are some average decibel measure comparisons for various household appliances.
| Appliance | Noise level (decibels) |
| Laptop | 40 decibels |
| Heat pump noise limit (measured from nearest neighbouring property) | 42 decibels |
| Refrigerator | 42 decibels |
| Outdoor air conditioning unit | 46 decibels |
| Dishwasher | 65 decibels |
| Vacuum cleaner | 85 decibels |
If your heat pump stays within the allowed levels, it should not cause any real noise nuisance to neighbours when sited outside. Your air source heat pump could actually be much louder than 42 decibels if you are standing right next to it — it is the value measured from the nearest neighbouring property that is important.
Are Heat Pumps Noisy Compared to Air Conditioning Units?
Both air conditioning units and air source heat pumps produce a similar level of noise. There may be variations, depending on the make, model and power rating of the units.
If your property is in close proximity to neighbours and noise is likely to be a key consideration, you should speak with installers to find out the air source heat pump units that are likely to have quietest operation and therefore be best for your home. In some instances, ground source heat pumps can have quieter operation because there is no fan required to extract the heat from air as the heat is instead extracted from the ground.
Why Do Air Source Heat Pumps Produce Noise?
Heat pumps consist of moving components — fan, compressor, AC condenser, expansion valve, evaporator – which will naturally generate some noise, particularly the fan and compressor. Air passing through the heat exchanger can produce vibrations or a constant hum, which vary in intensity depending on how hard the heat pump is working.
With the noise levels generated by a heat pump being quiet and consistent, effectively a kind of ‘white noise’, this means the noise is often barely noticed and you are unlikely to run into problems with neighbours complaining.
How Long Should A Heat Pump Be Left Running?
Heat pumps are intended to run for extended periods of time, and you can leave them running throughout the day and overnight. In fact, many heat pump brands recommend that your heat pump is not turned off at all in order to maintain a comfortable temperature rather than having to keep heating your home from much colder temperatures, which can actually work out less economical.
Heat pumps heat at low levels over long periods of time, so while it may be recommended to lower the temperature of your heat pump overnight, the general advice is to keep it turned on. This is because the cost of heating your home in the morning would likely be higher than if you’d left the heat pump running overnight at the lower temperature.
What If My Heat Pump Is Too Noisy?
If your heating system is making any noises out of the ordinary, or there is excessive rattling or buzzing sounds, you should get your it checked over by a heating engineer. They will be able to determine whether the noise being generated is excessive or anything to be concerned about.
While your heat pump will be noisier when it is working harder, any noticeable difference in the usual running noise levels are often a signal to get your air source heating system looked at. Sometimes, there is a simple solution to excessive noise and that is to use vibration-reducing dampeners, either under the heat pump unit or onto the bolts securing the compressor.
Another other issues with sound levels during operation will be diagnosable by an engineer. In some instances it may be that your original heat pump installation was not done correctly, or a component part of your heat pump just needs replacing.
Are Heat Pumps Louder In The Colder Months?
Heat pumps create noise of variable intensity depending on how hard they are working to draw warm air into the compressor. When it is colder, your heat pump will be working harder because the outside air temperatures, from which heat is extracted, will be much lower. This will result in higher noise levels.
All the internal components, including the fan and heat exchanger, will be under greater strain, so it’s perfectly ok for your heat pump to be making more noise during the winter months. When it is a problem is when operation becomes excessively noisy or that the noises made suddenly change. If this occurs, get your air source heat pump checked out by a heating engineer.
Are Modern Heat Pumps Quieter?
Improvements in modern heat pump technology mean they are generally becoming quieter operating and the levels of noise pollution are becoming less and less. The first heat pumps manufactured tended to be far noisier, so if you have one that is around 10-15 years old, it is likely to generate much more noise during operation and you might be thinking about updating it.
As technology continues to develop, and more and more households adopt heat pumps, it’s likely that heat pump noise will reduce further. While heat pumps will never be entirely noise-free, the amount of noise they generate will become less of a consideration for those looking to install a heat pump.
Heat Pump Noise Summary
While air source heat pumps can be heard operating, they are significantly quieter than they used to be, and an outdoor unit when installed correctly should not cause any real noise issues for nearby neighbours. While the UK legal limit for the volume of a heat pump is 42 decibels (measured one metre from the nearest neighbouring property), this level isn’t much more than the hum of a refrigerator.
If you have any concerns about the current level of noise being made by your heat pump, it is advisable to get it checked by a heat pump engineer. If you’re considering having a heat pump installed, get in touch and see what Eco Grants can do for you.