The primary advantage of this type of system is their small size and zoning flexibility. While some units are single zone (have only one indoor unit) there
are systems that can have up to 4 indoor units, all operating on their own thermostats. This can save energy and money as you only condition the spaces
when they are being used.
Another advantage is their ease of installation, and the various styles of indoor units they can be fit to suit any décor and be quite unobtrusive. Also, since they have no ducts, they avoid energy losses associated with ducted systems. Duct losses can account for as much as 30% of energy consumption (according to the U.S. Department of Energy) especially when you run ductwork through unconditioned space, such as attics and crawl spaces.