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Air conditioners' noise can cause sleep disturbance |
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Wednesday, 14 February 2007 |
 Studies in Sweden show that low frequency noise (typically 20 - 200 Hz) from air conditioning units, such as air-cooled condensers placed on the flat roofs of apartment buildings, can be disturbing for occupants, particularly for rooms facing the internal courtyards, reports "JARN" magazine.
Eight groups of buildings in the centre of Goteborg were chosen for the study and conclusions were based on answers to a questionnaire. Installations varied in the noise they produced in the internal courtyards - measurements ranged from 48/52 dBA for the "low" category to 57/62 dBA in the "high" category. These corresponded to noise levels in the rooms from 23 to 30 dBA.
Sleep disturbance was the main problem, mentioned by two thirds of occupants exposed to the higher levels and by one third of those with levels of 23 dBA.
The critical influence on feelings of discomfort was found to be the combination of continuous sound in the low frequency spectrum rather than the sound intensity itself. The study highlights the need to provide more low-frequency attenuation to compressor and condenser package design. The leader of this project was Kerstin Persson Waye at the Sahlgrenska University Hospital, Goteborg. |
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