Do I need to turn on the AC when using the car heater in winter?

[VanBeckett]

In winter, you do not need to turn on the AC when using the car heater. The correct method to use the car heater is as follows: 1. Start the engine and let it warm up until the temperature gauge reaches the midpoint. 2. Turn on the heating system and set the air circulation to external circulation to expel the cold air from the car. 3. After 2 to 3 minutes, switch the air circulation to internal circulation. The car air conditioning system is an air conditioning device installed in vehicles, and its functions include: 1. Cooling, heating, ventilating, and purifying the air inside the cabin. 2. Providing a comfortable environment for passengers. 3. Reducing driver fatigue and improving driving safety.

[LaCaden]

After years of driving, I've found that turning on the AC isn't always necessary when using the heater in winter. In dry weather, the heater alone provides enough warmth, and running the AC just wastes fuel. However, during rain or fog, the AC's dehumidifying effect is obvious—it quickly clears fog from the windshield, greatly improving visibility. If the AC system is too old, prolonged use may cause excessive noise, which isn't worth it. I've developed a habit of turning off the AC when starting the car, only pressing it briefly when fog appears. After all, winter heat comes from the engine's warmth, so whether the AC is on or off makes little difference. But safety comes first—when humidity is high, the AC must be used to defog, otherwise driving becomes too dangerous.

[VonJayla]

As an average driver, I often encounter this issue. In winter, the car is cold, and turning on the heater quickly warms it up, but what is the AC doing? The AC is originally for cooling, but pressing it in winter removes moisture, making the warm air less humid and stuffy. For example, when the windows fog up, turning on the heater plus the AC can clear them instantly. However, I don’t keep it on all the time, as that would increase fuel consumption—normally, just the heater is fine. I only turn on the AC for a few minutes when the humidity inside is high or right after starting the car. In short, it depends—on dry days, I save fuel by not using it, but on damp, cold days, it’s practical to turn it on.

[ColtonLynn]

I prioritize fuel efficiency, so I only occasionally turn on the AC when using the heater in winter. It uses the compressor for cooling and dehumidification, but the hot air dries the air quickly, especially great for clearing windshield fog. If left on for long periods, it slightly increases fuel consumption, which isn't cost-effective. I only press the AC button when there's heavy fog and turn it off immediately after use. If the car's sensors are good, they'll adjust automatically – fuel savings and convenience are key.