A huge share of the housing in Somerville, Cambridge, Chelsea, Everett, and East Boston was built before central air existed: triple-deckers, two-families, capes, and brick rowhouses heated by radiators and cooled by whatever fits in a window. Running ductwork through those buildings means dropped ceilings, lost closet space, and a lot of plaster dust, which is why most owners never do it.
A ductless mini split skips all of that. One outdoor unit connects through a small line set to one or more indoor heads, each controlling its own room. The lines run through a three-inch hole and down the exterior wall in a line-hide channel, so a typical single-zone installation is finished in a day with no demolition. Multi-zone systems can serve a whole floor, or a whole unit in a multi-family, from a single outdoor condenser.
The same system heats. Modern cold-climate mini splits are heat pumps, so the head that cools a top-floor bedroom in July keeps it warm in January, often at a lower cost than the electric baseboard or the oil burner it replaces. For a third-floor unit that bakes in summer and never gets enough heat from the boiler in winter, this is usually the single most noticeable upgrade an owner can make.
Placement is where experience shows. A head needs to throw air across the room rather than straight at a bed or a desk, the condensate line needs a real downhill path, and the outdoor unit should sit on a stand above snow height, not on the ground where it will ice over. Garcia Services HVAC designs and installs ductless systems throughout Greater Boston and services every major brand, and every new installation includes its first maintenance visit free.