Furnace and AC replacement in Quantico.

The air station’s 1991 to 2020 normals show 4,002 heating degree days and 1,512 cooling degree days a year, a January average low of 28 and a July average high of 88. Both halves of a system work real seasons here. A furnace and a condenser that went in the same year have worn on the same schedule, and when both are old, replacing them together makes it one project.

More than half the Town’s 370 homes sit in duplexes and small apartment buildings, where each unit usually has its own pair: a furnace or air handler in a closet, a condenser on a pad outside. An owner with several units of the same age is looking at several aging pairs. Ask for each unit as its own written line, with both halves’ ages read from the tags, so the oldest goes first.

In a house from before 1940, the ductwork came decades after the walls. County address records date at least nine of the 13 homes on 5th Avenue to before 1940. A new pair set onto the old duct path performs like the old one, so the tech measures the airflow in the rooms first and says in writing if the ducts, not the equipment, are the trouble.

Where the new condenser goes matters on this stretch of the river. The air station recorded gusts of 58 mph in February 2015 and 59 mph in February 2017, and a tree came down on Fuller Road in an August 2021 thunderstorm. Set the pad clear of overhanging limbs, with room for air around it, and the next blow has less to throw at it.