When buying Mini-Split Air Conditioning Systems, your first decision is whether you need a single zone or a multi zone system. Single zone systems use one indoor wall mounted unit, and one outdoor condensor.
General uses for this would be in rooms that are new additions to a house where the existing A.C. system does not reach. Another example would be in a windowless room where traditional air conditioners can not be installed.
Multi zone systems are generally used for whole houses where multiple rooms or zones need to be cooled.
This might be the case if you want to cool a large home, but central air duct work is not an option. These systems use 1 or more outdoor condensors and 2 or more indoor wall mounted units.
Tip: Never use a multi zone condensor with just one indoor unit. This can cause short circuiting and even permanent damage.