There's nothing worse than turning on the heat on a cold Carolina night and feeling cold air pour out of the vents. If your furnace is blowing cold air, don't panic — several of the causes are simple. Here's what to check, and when to call a technician.
1. Your thermostat is set to "ON" instead of "AUTO." This is the most common and easiest fix. When the fan is set to "ON," it runs constantly — even between heating cycles — so it blows room-temperature or cool air when the burners aren't firing. Switch it to "AUTO" and the fan will only run when the furnace is actually heating.
2. The furnace is still warming up. When a heating cycle starts, the fan may kick on for a moment before the air is hot. If it warms up within a minute or two, that's completely normal.
3. Overheating and safety shutoff. If a dirty air filter or blocked vents restrict airflow, your furnace can overheat and shut off the burners for safety — while the fan keeps running, blowing cold air. Check and replace a dirty filter first.
4. Ignition or gas-supply issues. On gas furnaces, a problem with the igniter, flame sensor, or gas supply can stop the burners from firing while the blower still runs. These need a professional.
If a filter swap and a thermostat check don't fix it, it's time to call in a pro before you're left in the cold. Reinhardt Heating and Air offers prompt heating repair across the region, 7am to midnight — give us a call.