I have an open concept living area with a vaulted ceiling.  A small AC unit was in the window but it did nothing to keep the room cool.  It generally hit 85 degrees daily in the summer.  Once I had this unit installed, it felt like I had central AC.  It is quiet and powerful.  In fact, it is so powerful that my bedroom and bathroom were also cooled off.  I only used my bedroom AC twice the rest of the summer because this unit cooled off my entire condo.  I highly recommend this AC.