The caller came right to the point: “What’s that smell?”
A homeowner reported a strange, persistent odor whenever the heat ran. He’d heard stories about critters getting into furnaces, but this was different – more chemical than organic. His system was over 35 years old. Could it be that something inside was actually melting?
Enter the detective: Harold Wilkes, owner of Mechanical Extremes.
Harold shut the system down, pulled the panels, and worked his way to the heat exchanger—the heart of the furnace where air warms before it’s sent through the house. No signs of wildlife. No cracked housings. Then he spotted it: a tube of silicone caulk that had somehow fallen through a register and migrated into the heat exchanger compartment. Under heat, the tube softened and melted into surrounding surfaces, releasing that odd, plastic-like smell.
How did it happen? A DIY mishap. An errant tube of silicone caulk must have fallen down through an open vent and ended where no tube should ever go. And that’s what caused the persistent, chemical odor whenever the burner fired.
With the furnace’s age and the extent of the contamination, the homeowner chose the smart path: a replacement with a modern, efficient (and odor-free) unit. Within hours, the upgrade was in, the system commissioned, and the house warming comfortably.
The Happy Epilogue
Newer furnaces don’t just eliminate mystery smells—they often deliver more even comfort, quieter operation, and, as many Mechanical Extremes customers say, a pleasant surprise on the utility bill. Properly sized and tuned equipment can mean fewer on/off swings and smarter use of fuel.
Need help tracking down mystifying symptoms? We’d love to hear from you. (517) 812-2482.
