You may already have some familiarity with ductless mini-split AC systems in Staten Island, NY. You can find them in businesses and in older apartment complexes. When you see what looks like a small-sized window AC up on the wall—and with no actual window behind it—that’s the air handler part of a ductless mini-split.
Instead of exhausting the heat from the room directly out the back of the unit the way a window AC does, the air handler of a ductless system connects through refrigerant and power lines to an outdoor condenser cabinet that looks the same as the condenser cabinet of a standard central air conditioner. This outdoor unit can connect to multiple indoor air handlers (from 4 to 8 depending on the capacity of the system) so cool air can be sent into rooms all around the house.