Split ductless air conditioning typically supplies conditioned and heated air to a single or a few rooms of a building, without ducts and in a decentralized manner. It has been used for many years and is very popular in Asian and European countries.
In Canada, homes without duct work (such as heritage homes or homes with boiler systems) can enjoy AC air conditioning too thanks to mini split ductless air conditioning systems. Ductless heat pumps can also be used as garage heating source when natral gas is not available or difficult to run.
Split ductless air conditioners are able to cool different sized areas based on the size of the unit. To know what size you need you will need to know how many square feet each room is that you want that unit to cool.