Should You Turn on AC When Using Car Heater in Winter?

[DiLyla]

When using the car heater in winter, you should not turn on the AC. The warm air comes from the heat generated by the engine during operation: After the engine's cooling system dissipates heat from the engine, a fan directs this heat into the car cabin to provide warm air. When the heater is not in use, the fan stops, and the heat vent closes, allowing all the dissipated heat to escape into the atmosphere. Therefore, the car heater reuses waste heat and does not consume additional fuel. To quickly raise the cabin temperature in cold weather, start by allowing the engine to warm up after ignition. Once the engine temperature gauge reaches the midpoint, turn on the heater and set the air circulation to external mode. After 2 to 3 minutes, switch the air circulation to internal mode.