Does an AC or heat pump's outdoor unit cause noise nuisance in apartment buildings?
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Outdoor unit noise in apartment buildings often raises questions. The noise level depends on the device, where it's placed, and the measurement point. Modern AC's and heat pumps are designed to run quietly and meet the regulatory requirements for both indoor and outdoor spaces.
There are legal limits on the noise an AC or heat pump can cause, both inside and outside the building: indoors, nighttime noise can't exceed 33 dB, and occasional noise can't exceed 45 dB, while outdoors, the average sound level can't exceed 45 dB and the peak sound level 50 dB.
In the newest models, the outdoor unit's noise level is typically 45 dB measured about a meter away. Many models also have a night mode, which drops the sound pressure considerably. So a correctly installed unit is unlikely to exceed these limits in practice.
Noise level in a neighboring apartment
Indoors, Valvira's Decree on Housing Health applies, under which technical equipment's nighttime noise level can't exceed 33 decibels (dB) in living spaces between 22:00 and 07:00. Occasional noise is allowed to be higher, but it can never exceed the 45 dB limit. (Valvira, 8/2016)
Under Valvira's guidance, indoor noise measurements must be taken in the living area, typically at head height or around the head area of a person lying in bed. Measurements can't be taken closer than 0.5 meters from room surfaces without a specific reason, and windows, exterior doors, and vents must be closed during measurement.
It's worth noting that manufacturer-stated noise levels are typically measured about a meter from the outdoor unit. Once you account for how sound attenuates with distance and the sound insulation provided by the building structure, it's in practice very unlikely for indoor noise limits to be exceeded in neighboring apartments.
The outdoor unit's effect on a neighbor's balcony
A situation where an AC or heat pump's outdoor unit sits close to a neighbor's balcony needs particular attention. Under the Ministry of the Environment's decree (796/2017), the noise level can't exceed a 45 dB average sound level or a 50 dB peak sound level on a balcony. If the outdoor unit's stated sound pressure is, say, 45 dB measured a meter away, the sound drops by about 6 dB every time the distance doubles. That means at two meters, the noise level has already dropped to around 39 decibels. Any obstacles, such as balcony glazing or partition walls, attenuate the sound further still.
So a correctly placed and installed outdoor unit is likely to meet the noise requirements on a neighbor's balcony too. Even so, it's important to factor in where a neighbor's balcony is located when planning placement, and to install the outdoor unit as far away as reasonably possible.
Why installation matters for preventing noise nuisance
Correctly placing the outdoor unit plays a key role in minimizing noise nuisance. The unit is never mounted directly to a wall structure, due to vibration and resonance, but is instead installed, for example, on the balcony floor on vibration-damping rubber pads. This installation method, combined with modern units' quiet operation, ensures noise levels stay within the allowed limits both indoors and outdoors.
If it can be shown that the AC or heat pump meets the regulatory guidelines and that the installation is done structurally correctly, the housing company will often grant permission for the installation.Read more on this in this article.
