If you are experiencing a burning odor coming from your AC, your immediate concern is probably a fire.
But, this isn’t the case.
If you just turned on your heater, heat pump, or furnace for the first time after a long while. You might notice a burning smell. This is because of months of inactivity, letting the system collect dust. When you first turn it on, the dust is going to burn off. As it does so, it releases a mild burning odor. This is nothing to worry about. The scent odor is harmless and goes away on its own within moments. If you haven’t changed the AC system air filter lately, then it might be clogged. When air filters can clog down with an excess of debris, it restricts airflow. That stains the components, like the fans and motors, throughout the system. This can result in overheating and a burning smell from components and parts. Check the air filter for clogging and replace it with a fresh one. Every HVAC system has its capacitor to power up the motor. When a capacitor fails, the engine might overheat, resulting in that dreaded burning smell. Capacitors can break for many different reasons, whether everyday wear and tear, power surges, or overheated circuitry. In cases like these, the capacitor is likely to need replacement. Your best bet here is to turn the whole system off and let a professional handle it. A faulty motor might also be a source of a burning smell. The motor bearings can wear down and create overheating. If you have never noticed the burning smell before, turn everything off and lubricate your bearings immediately. That should prevent your motor from totally burning out so you can avoid having to replace it. Other causes of a burning smell may be burning electrical components if you also are experiencing a rotten egg or sulfur odor. In this case, make sure to turn off your system and call a HVAC professional immediately to be safe.