Ductless mini splits in Haymarket.

Bull Run Mountain Estates is the part of Haymarket likeliest to have no ductwork at all. Its median house was built in 1978, 225 of its 505 homes went up in the 1970s, and close to four owner homes in ten heat with electricity. In a house of that age, electric heat can mean baseboard heaters room by room rather than a heat pump on ducts, with summers left to window units. A multi-zone system covers both seasons from one outdoor unit: two zones run $11,000 to $15,000 installed, three run $12,500 to $18,000.

Dominion Valley and Piedmont are mostly 2000s houses, and their ductwork usually ends where the builder’s drywall did. The basement is the common gap. One finished after move-in often gets a supply run or two tapped off the main trunk and no return of its own, so it runs cold in January. A head down there gives that level its own setting without stealing air from the floors above.

Inside the town limits the Town Code treats any structure 50 years or older as historic, and only about one home in twenty-five in town predates 1980; the Town’s guidelines describe older homes east of the old center along Washington Street. A house that old may have been heated without ducts from the start, and ductless brings it cooling without cutting duct chases through plaster. The outdoor unit still has to be screened from public view, by a wall, a fence or planting that screens all year.

Anywhere in 20169, a mini split needs a new circuit from the panel, and Prince William County lists a new circuit among the jobs that always take a permit. Inside the town, the Town’s Zoning Approval comes first. Where an association governs the outside of the house, the County tells owners to check its covenants; an outdoor unit on a new pad is an exterior change.