Furnace replacement in Waterford.

The median owner home in ZIP 20197 was built in 1996, so the furnace that came with it is about thirty years old, and about a third of the owner homes date from before 1980. Propane heats more than half of them, and the Census finds none on natural gas, so a gas furnace in Waterford means a propane furnace set up for the tank in the yard. At that age, a replacement is as likely as another repair, and keeping a newer air conditioner is often possible.

Swapping a gas furnace in Loudoun takes a permit. Since October 2025, a swap at the same BTUs in the same spot skips plans review, and anything bigger or moved does not. Ask the installer to show the old furnace’s input rating next to the new one’s before you agree to either size. A house measured as it stands today can land on a different number than the furnace that came with it in 1996.

The Purcellville station logs 114.7 nights a year at or below 32 degrees and 11.6 days when the high stays there too. The cold spell of January 23 to 31, 2026 put Western Loudoun under Extreme Cold Warnings, with the coldest nights on the 27th, 30th and 31st. A furnace that fails on a night like that is the argument for replacing a tired one in October instead of waiting for the worst of January.

If the new furnace changes how the house vents, the exit through a wall can show from the street. In the central village that is an exterior change, and Loudoun’s Waterford Historic District has its review committee approve most of those before work starts. Ask whether the vent stays where it is. A newer high-efficiency furnace vents in plastic pipe, and an older one often vents up a metal flue, so the two may not share a path.