Common Furnace Problems and How to Fix Them

Furnace Troubles? Here’s What Might Be Wrong

A broken furnace in the middle of winter is no fun! If your heating system isn’t working right, don’t worry—many issues are easy to fix. Before you call for repairs, check out these common furnace problems and what you can do to get the heat back on.

Furnace Won’t Turn On

Possible Causes: Dead thermostat batteries, tripped circuit breaker, or a safety switch issue.
Try This: Replace the batteries in your thermostat, check your breaker panel, and make sure your furnace door is fully closed (some have safety switches that prevent them from running if the door is open).

Blowing Cold Air Instead of Heat

Possible Causes: Thermostat settings, dirty air filter, or pilot light issues.
Try This: Make sure your thermostat is set to “heat” and not just “fan.” Also, check if your filter is clogged—it can restrict airflow and cause heating problems. If you have an older gas furnace, check if the pilot light is out.

Weird Noises (Banging, Rattling, or Whistling)

Possible Causes: Loose parts, dirty burners, or airflow issues.
Try This: If you hear banging, it might be a dirty burner causing delayed ignition. Whistling could mean a clogged filter. If parts seem loose, turn off the furnace and call a professional for a safety check.

Furnace Turns On and Off Too Often

Possible Causes: Dirty air filter, thermostat placement, or airflow problems.
Try This: A clogged filter makes your furnace overwork, so replace it if it’s dirty. If your thermostat is near a heat source (like a vent or sunny window), it might be reading the temperature incorrectly—try moving it to a better spot.

Strange Smells Coming from the Furnace

Possible Causes: Dust buildup, gas leaks, or mold.
Try This: A slight burning smell when you first turn on your furnace is normal—it’s just dust burning off after months of not being used. But if you smell gas, turn off your furnace immediately, leave your home, and call a professional.

Not Sure What’s Wrong? Call the Experts!

If your furnace still isn’t working right, it’s best to call in the pros. At Proper HVAC, we offer expert furnace repair services in San Diego County to get your heat back on fast. Don’t wait—give us a call today!