Yes, portable air conditioners are quiet as compared to window ac. Window AC is slightly louder than a portable unit. So I call a portable air conditioner as a quiet portable air conditioner. Portable air conditioners are easy to install. A window ac requires a place to install, a portable air conditioner can be placed just using clip-in of its exhaust to a window frame. Portable air can be moved anywhere whenever required. Since I am using a portable air conditioner for many years I can surely confirm that portable air conditioners are quieter than window ac.