Do You Need to Turn on AC When Using the Heater?
3 Answers
You do not need to turn on the AC button when using the heater. The AC button is the switch for the car's air conditioning compressor, which is used for cooling. The car heater utilizes the internal heat circulation of the vehicle and does not require the air conditioning compressor to work. Therefore, to use the heater, you only need to adjust the fan speed and set it to the heating position without turning on the AC switch. Steps to turn on the car heater: 1. After starting the car, wait for about 8-15 minutes until the water temperature reaches the normal operating temperature, then you can turn on the heater. 2. Adjust the air conditioning circulation mode to internal circulation. 3. Switch to the heating mode, which may be indicated by a red zone or a sun symbol depending on the vehicle.
When using the car heater, you don't need to turn on the AC button at all—that's the air conditioning compressor switch, specifically for cooling. In winter, the warm air comes from the heat generated by the engine. Just turn the temperature knob toward the red zone and increase the fan speed to get hot air. Keeping the AC on actually increases fuel consumption, so the first thing I do when getting in the car is turn it off. Of course, it's a different story when the windshield fogs up on rainy days—the AC's dehumidification function really comes in handy then. But I usually prefer to first turn on the external air circulation to let the cabin air flow, then raise the temperature, and the fog typically clears in two or three minutes. In northern areas where it's -20°C, just turning on the heater for three minutes can make the cabin so warm you can take off your coat.
There's really no need to turn on the AC for heating. After driving for over a decade, I simply turn the temperature knob to the red zone. Once the engine warms up, heat comes naturally - like in my old Toyota, setting it to 26°C makes hot air blow out steadily. However, in summer you must press the AC button for cooling as the compressor needs to activate. When windows fog up in winter, using AC for dehumidification actually works faster than warm air, though it increases fuel consumption by about 10%. Here's my trick: set air direction to windshield, switch to external circulation, turn temperature to maximum, and fog usually clears within a minute. Remember, heating relies entirely on engine temperature - it only works after the coolant warms up when starting a cold engine.
