Zahid Ali
4 min read · Furnace
1. Short Cycling — Turning On and Off Repeatedly
If your furnace starts, runs for a few minutes, shuts off, and starts again in a loop, it's short cycling. This usually signals an overheating issue (often a clogged filter or blocked vent), a failed flame sensor, or a problem with the heat exchanger. Short cycling wears out components fast and should be addressed promptly.
2. Yellow or Flickering Flame
A gas furnace burner should produce a steady blue flame. Yellow or orange flames — or a flame that flickers irregularly — can indicate incomplete combustion or a cracked heat exchanger. Both are safety issues. If you see a yellow flame, call us before running the system.
3. Unusual Sounds
Banging on startup typically means a delayed ignition — gas is building up before it fires. Squealing suggests a worn blower belt or bearing. Rattling can indicate loose panels or a cracked heat exchanger. Any sound that wasn't there last season warrants a look.
4. Rising Gas Bills Without Explanation
If your heating bills are climbing but your usage habits haven't changed, your furnace is losing efficiency. This is common in systems with dirty heat exchangers, worn burners, or failing draft inducers. A tune-up often resolves it; if not, replacement may be the answer.
5. Age Over 15 Years
Most gas furnaces have a reliable lifespan of 15–20 years. If yours is in this range and showing any of the signs above, start planning proactively. Emergency replacement in the middle of a cold snap is more expensive and more stressful than a scheduled swap before the season.
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