Noisy air conditioners are one of the common problems encountered. The reasons may be of a singular nature or due to multiple faulty functioning in the air con.
One reason for a noisy air conditioner is a choked fan coil or dirty outdoor condenser. To ascertain this, put your hands in front of the blower. You will be able to feel that the air con draft (wind) does not blow out smoothly, or that only pockets of draft (wind) are emitted from certain sections.
Another reason could be an off-balanced air con blower due to dirt build-up. This results in unbalanced spinning by the rotary of the blower, leading to vibration which then produces noise.
Faulty motor bearings or abnormal gas pressure in the air fan coil pipe may also cause a noisy air con.
The solution to a noisy aircon is two-pronged. First, regular aircon service by a professional contractor will be able to keep the air conditioner filter and outdoor panel clean. As mentioned, a noisy air con may be due to one reason, or concurrent faulty parts. Pertinently, a professional technician will be able to detect any underlying problems and prevent them before they arise.
Secondly, if you wish, you can proactively prevent the build-up of dirt and bacteria in the filter and panel by wiping them with a wet cloth once in 2 weeks.