Video · Furnaces and Heating
Rusty Furnace on a No-Heat Call, and the New One in the Snow
Rust inside a furnace means water has been getting in, usually from a dripping AC coil, a humidifier or the venting. It eats burners and the heat exchanger over time, and a rusted heat exchanger is a safety problem.
Job footageSwiftPro
- Topic
- Furnaces and Heating
- Length
- 0:49
- Posted
- August 3, 2026
- Shot by
- The SwiftPro crew, Northern Virginia
What you’re seeing in this video
It starts on a no-heat call. An old gas furnace stands in a closet with its panels off, and the inside of the cabinet is rusty enough that one of the techs calls it out on camera.
Next, two techs carry a boxed new furnace up a townhouse sidewalk with snow on the ground. Then a bald tech in red gloves and a bearded tech in a black hoodie and cap wire it in.
Why it matters in your house
- Look above the furnace. An AC coil with a clogged drain pan drips straight onto the burners and heat exchanger below it, and that's where a lot of furnace rust starts.
- Rust flakes fall into the burners and throw off the flame. Rust through the heat exchanger can let exhaust into the air you breathe, which is why a working CO alarm matters.
- Surface rust on a cabinet panel isn't urgent. Rust inside on the burners, heat exchanger or flue connection deserves an inspection soon, and in an older unit it often tips the decision to replace.
Is a rusty furnace dangerous?
It can be. Light rust on the outside panels is mostly cosmetic. Rust on the burners, inside the heat exchanger or at the vent connection can affect combustion and, in bad cases, let carbon monoxide escape. Have it inspected, fix the water source, whether that's a coil drain or a vent, and keep CO alarms working in the meantime.
Want it done at your place? See Furnaces and Heating at SwiftPro or call (703) 997-9757.
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