Furnace tune-ups in Middleburg.

Utility gas heats only 41 of the 927 owner homes across 20117. Electricity heats 582, usually through a heat pump, and propane from a tank on the property heats 187. Either way it’s the same $99 a system. On propane the tech holds the pressure readings to the propane figures on the furnace’s rating plate, not the natural gas ones, and watches the burners light in order.

January nights at the Purcellville co-op station, twelve miles north, bottom out at 24.5 degrees on average. Middleburg did worse on January 23, 2025, when a weather station in town that the Weather Service lists read 4 below zero, unofficially. A year later an Arctic outbreak brought wind chills of zero to 10 below across the Virginia Piedmont. That’s when a heat pump hands much of the job to its backup, electric strips or a paired propane furnace: the half of the system that sits idle until the night it matters.

The oldest houses heat differently. Of the ZIP’s 1,416 homes, 333 went up in 1939 or earlier, and a house that age often started with a boiler and radiators. Some still run them on propane, and a boiler tune-up is the same $99. Where a furnace or boiler still vents into an old masonry flue, the safeties it tests include the switch that shuts the burner off if exhaust spills back into the room.

Snow is the other test. After the January 2016 blizzard a trained spotter in Middleburg measured 34 inches, an unofficial count. A high-efficiency propane furnace draws its air and sends its exhaust through two plastic pipes on an outside wall, and a drift over their ends shuts it down, so dig them out with the walk. When snow-loaded trees take the power, as they did across Loudoun in February 2010, a propane furnace stops too: it needs electricity to light and run its blower. If it doesn’t start up again once the power returns, call us.