Ductless mini splits in Clifton.

The Town of Clifton is a quarter square mile of frame houses, and the Town’s history page says almost all of them are more than 120 years old. Its design guidelines describe clapboard siding, standing-seam metal roofs and stone foundations, on houses built long before anyone ran ductwork for cooling, so whatever cooling they have came later. A mini split suits them because a wall head needs only a hole a few inches across for its line set, where ducts need chases cut through plaster and floors never planned for them.

The outside is where the Town comes in. The whole town is the Clifton Historic District, and the Town’s FAQ says changing the outside of a building takes a certificate of appropriateness from its Architectural Review Board. An outdoor unit on a new pad and a line set cover running up the siding are both changes you can see, so settle where they’ll go, and get the Board’s answer, before the install date. The permit itself is Fairfax County’s, once the Town has signed off by letter.

Outside the town line, Clifton is mostly 1980s and 1990s houses with ductwork throughout, and the ductless job there is the space finished later. Six in ten homes in 20124 have nine rooms or more, so there’s often a basement turned into a rec room, a sunroom off the kitchen or a room over the garage that the original system was never sized to reach. One head in that room, on its own outdoor unit, leaves the rest of the house alone.

The ZIP also holds about 760 townhouses, almost none of them out on the acreage, and their top floors often run warm on a single thermostat. On the five to ten acre lots, a detached garage or workshop, if the property has one, can get a head and an outdoor unit of its own. And the two newer streets inside the town, Water Street’s Frog Hill and Clifton Heights Lane, each have a homeowners association, so check its rules as well as the Board’s.