This is the Queens system.
Brick rowhouses, semi-detached homes, and pre-war houses that never had a duct in them. Adding ductwork to those buildings means tearing up ceilings and losing closets. A mini split skips all of it: a compact condenser outside, a head on the wall inside, and a three inch hole between them.
It is also much quieter and far more efficient than running a separate unit in every room, and nothing has to come out in October. Multi-zone systems let each bedroom set its own temperature, which ends the thermostat argument in a house where one person sleeps cold and another sleeps hot.
