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A neighbour’s heat pump or air conditioner: humming, placement and agreements
An outdoor unit may hum, rattle or transmit vibration into another home. How can you identify the source and arrange a useful technical check?
Start with what you hear and when. The nearest unit is not necessarily the source. A short, controlled comparison with its operation can help.
The local rules and reporting routes below apply in England.
What pattern do you hear?
Record the start and end time, the room or outdoor location, and whether the sound is constant or changing. Is it especially audible at night, in hot weather or when the heating is working harder? Also write down when the sound actually drops out.
Ask which equipment is running at those times. Keep suspected sources separate from confirmed ones. A phone recording may illustrate the sound, but does not establish whether a legal noise limit is exceeded.
Why can the placement make a difference?
In an installation, both airborne noise and vibration from fixings can play a role. The positioning in relation to facades, windows and other houses therefore requires attention. The owner should discuss with the installer which transmission route is plausible.
Describe the practical impact, such as broken sleep. Request an inspection or agreed test before prescribing an expensive change.
What can you do together first?
Compare one clear moment
Compare the sound during a safe change controlled by the owner or installer. Do not alter essential settings at random.
Arrange an inspection and feedback
Ask who will contact the installer, what information will be collected and when you will discuss the outcome. A temporary usage agreement is only useful if it is technically justified and feasible for both households.
A calm opening
“I hear a recurring hum at my bedroom in the evening. Could that be related to your outdoor unit? Maybe we can compare one moment and ask the installer about the placement if that is indeed the source.”
Which modifications can you have examined?
Maintenance and settings
Ask the installer about maintenance, quiet modes and scheduling where available. Check how settings affect heating or cooling performance as well as noise.
Mountings and vibration
Have the installer check supports, fixings and pipe contact with the building. Any vibration isolation must suit the equipment and its load; generic rubber pads will not solve every hum.
Move or shield
Before relocation or an enclosure, ask for the expected improvement at the affected room and an assessment of airflow, heat, servicing access and permissions. Do not block vents or box in the unit yourself.
Do you feel vibrations mainly via floor or wall? Also read the guide on impact noise. Read the related guide
Which rules apply in England?
A council can investigate equipment noise that may amount to a statutory nuisance. Planning requirements for a particular installation are a separate question for the local planning authority.
Where can you get help in England?
Record where the sound is strongest and whether it coincides with start-up or night operation. Ask the owner to have the installer check the mounting and position. If needed, share your record with environmental health.
Sources and review date
Guide reviewed on 7 November 2026.
GOV.UK — How councils deal with noise nuisance
Keep the next step manageable
Use the free incident diary for a few representative observations, any agreement and improvements. If you need outside help, see Who can help. State what happened, what you have tried and what you are asking the recipient to do. You do not have to keep approaching the neighbour if contact feels unsafe.
Would you like to write to your neighbours?
On the situation page you can see the CalmNotes bundle, its contents and the other support options.