Thinking about an air source heat pump but worried about noise? You are not alone. The question that many people give is whether these systems will be a nuisance to their home or to their neighbours. This guide explains how noisy an air source heat pump usually is, what affects the sound, and simple steps you can take to keep noise low. We will make it easy to understand and not complicated, to enable you to make a decision. Want to learn how an air source heat pump works?
How Loud are Air Source Heat Pumps?
The manufacturers use the measurement of sound in decibels (dB). A modern domestic air source heat pump typically makes between 40 dB and 60 dB at close range. In other words, to make that understandable to the layman:
- 30 dB is like a quiet library.
- Home or countryside at night has a 40 dB noise level.
- 50 to 60 dB is equivalent to the level of loud enough speech or office noise.
- Therefore, at the distances of 3-5 metres to the unit, one will hear a bit of hum or slight whir.
Note: This is hardly noticeable in most gardens but when the unit is located near to a bedroom window or an outdoor area of a neighbour, may come out intrusive unless you plan the location.
What Affects the Air Source Heat Pump Noise?
A number of factors alter the volume level of the unit both indoors and outdoors:
- Unit model and size Bigger units (higher kW) usually produce more sound, due to more air being moved.
- Newer high-speed low-noise models have more quiet fans and compressors.
- Sound does not travel far and it diminishes rapidly with distance. A unit positioned 5 metres away will be much quieter when compared to one that is 1 metre away.
- Direction is also important, it would be helpful to turn the unit away, not to the living areas.
Note: Look out for a less noisy air source heat pump but with grants available. Check If You Are Eligible!
Mounting and Installation
Rattle and vibration are due to a poor mounting system. This is minimised by use of anti-vibration feet and solid bases.
Surroundings
Hard surfaces, walls and fences may reflect sounds and increase the volume. Trees and fences are able to absorb or block some noise.
Background Sound
In large cities, there is the masking effect of the noise of traffic. You will find it more in the quiet rural places.
Operation Model
The speed of operation of the unit can be various. When it is cold outside it labours more and can be noisier.
Is the Noise of Modern Air Source Heat Pumps Less than those of the Older Ones?
Yes, new models tend to promote low sound and a better compressor technology. Two ratings published by manufactures are:
- Doppler shift in the frequency of the unit is also taken into account. To characterize the unit’s total noise output, the unit uses sound power (dB Lw).
- Sound pressure (at 1m to 3m dB) indicates the noise level required to determine the amplitude (loudness) at a specific distance.
- Ask those installing for measured sound pressure levels at 1 metre and to such distances as may be from potential neighbours (for example 3-5 metres).
This will be offered by reputable installers and well that gives an understanding of what it entails to your location.
Check out location tips in Understanding Air Source Heat Pumps Location Rules.
Planning, Regulations and Neighbours Issues
No national noise limit of domestic heat pumps exists but local councils intervene when there is a complaint by the neighbours. Some councils look towards British standards for guidance in their complaints (e.g. BS 4142 (industrial noise assessment), BS 8233 (sound insulation and noise levels) etc). If your property is in a conservation area or a listed building then you might need additional appetite.
To prevent being problematic, consult with neighbours prior to installation and provide the noise data of the installer. Complaints can be avoided in the future by good communication.
Practical Ways to Reduce Air Source Heat Pump Noise
There are a number of simple things that you can do to keep noise down:
- Choose a quiet model
Compare sound pressure values and choose one that has low dB values.
- Position it well
Locate the unit in an out of bedroom environment and other spaces of the neighbours. Aim for a clear airflow path.
- Provide anti vibration mount and solid base
Transmission into building walls was cut by a concrete pad or vibration damping feet of good design.
- Acoustic panels or screens that can be used
It will be compensated with purpose-built enclosures, sound absorbing fences or plant trellis. Make sure airflow stays good.
- Keep it maintained
A clean fan and tuned compressor have better running conditions, and this makes them run quieter. Annual servicing helps.
- Take into account distance and orientation of neighbourhoods
Even a few metres of shift may generate a big impact on perceived noise by neighbours.
Read Efficient Ways to Operate Air Source Heat Pumps in the UK.
What to Ask Your Installer
When you get quotes, ask for:
- Sound pressure level measured at 1m and probable neighbour distances.
- The location of the proposal and the distance at which the unit is located by windows and boundaries.
- What anti-vibration/acoustic will they fit?
- Past installation and customer testimonials.
The Way that Home Energy Guide can Help
Home Energy Guide helps you understand what to expect from an air source heat pump. We describe what noise ratings are, some simple checks to do on site however you are installing a noise producing appliance, and provide you with a checklist of questions to ask installers.
Our guides demonstrate typical acoustic solutions that can be used in the UK gardens and the balance between the noise control and the efficiency of the systems. Home Energy Guide will provide practical and straightforward guidance on the type of model to buy to ensure that you make a sound decision and how to position the unit in a way that minimises noise.
See our expert picks in Best Air Source Heat Pumps in the UK.
Frequently Asked Questions (FAQs)
No, the vast majority of pumps emit a slight humming sound and are silent at night, unless they are located near the windows. In the case of sound, you can reduce greatly by using a low-noise model and anti-vibration balance fitting.
Positioning has a big effect. Perceived noise can be reduced by simply a few metres away from a bedroom window or by installing a screen.
