Carbon monoxide is an odorless, invisible byproduct of combustion — and the reason every home with a gas furnace needs working CO detectors and an annual heating inspection. This isn't a scare piece; it's the checklist we'd give our own neighbors.
Where does CO come from in a heating system?
A healthy gas furnace burns cleanly and vents its exhaust safely outdoors. Problems start when combustion or venting is compromised — a cracked heat exchanger, a blocked or disconnected flue, or a burner starved of air. Age and deferred maintenance raise the odds of all three.
What are the warning signs?
From the equipment: soot streaks, excessive moisture on windows near the furnace, a pilot or burner flame that burns yellow and lazy instead of crisp and blue. From people: headaches, dizziness, or nausea that improve when you leave the house. And of course: any CO alarm. Treat an alarm as real, every time — get outside, then call for help.
Where should CO detectors go?
At minimum: one on every level of the home and one near sleeping areas. Test them monthly and replace units at the age the manufacturer specifies — detectors wear out just like smoke alarms.
What does an annual inspection actually check?
Our technicians inspect the heat exchanger, venting, gas connections, and combustion performance as part of seasonal furnace service — the whole-system diagnosis, applied to safety. It's the single best CO prevention there is. Book it as furnace service or roll it into annual maintenance.
Smell gas or have an alarm sounding right now? Leave the house first. Then call us — in winter, emergency repair runs 24 hours.