Finding the quietest air conditioners. Currently, the 50-60 dB range is as quiet as an air conditioner can get. As of 2015, some of the quietest ACs include: Carrier Infinity 19VS - 56 dB; Dave Lennox Collection XC25 - 59 dB; American Standard Platinum ZV - 55 dB; Understanding air conditioner sound levels. OK, so what do those numbers mean, though?