We use this air conditioner in our master bedroom.  We selected it because we read reviews that said it was less noisy than other air conditioners.  Unfortunately that hasn't been our experience.  In addition to regular AC noises, it rattles and vibrates and makes noises that suggest it isn't tightly assembled.  We bought two smaller air conditioners for our children's rooms at the same time and they're both quieter than this one.  I'm giving three stars because it does cool effectively and the noises are manageable if annoying.