Blue star air conditioners generally do a better job blowing air in one direction. That can be a problem if your window isn’t centered on the wall. To uniformly cool a room, you’ll need to direct air to its center, so check whether your A/C needs to blow air to the right or to the left. Some have fan arms that swivel. Models that scored excellent or very good in our noise tests are so quiet that the only sound you might hear is the fan running. Air conditioners that scored fair for noise could disturb light sleepers when set on low, and are distracting to all when set on high