Do I Need to Turn on AC When Using the Heater in the Car During Winter?

[EthanRose]

When using the heater in the car during winter, there is no need to turn on the AC. The warm air is generated by heating the air through the temperature of the vehicle's engine coolant and then blowing it into the cabin. The AC button represents the air conditioning's cooling function, also known as the air conditioning cooling switch, which is short for air conditioning system. The car's air conditioning cooling system consists of components such as the compressor, condenser, receiver-drier, expansion valve, evaporator, and blower. The functions of the car air conditioning system are: 1. To regulate the temperature, humidity, airflow direction, and speed inside the car, and to improve air quality through the filter; 2. To provide a comfortable environment for passengers, reducing travel fatigue; 3. To create favorable working conditions for the driver, ensuring safe driving.

[LeviLee]

I've been driving for over twenty years and encountered all kinds of weather conditions. In winter, I basically don't need to use the air conditioning since the heater works fine. The heater mainly relies on the heat generated by the engine operation, which is blown into the cabin by the fan, without any additional fuel consumption. The air conditioning compressor is used for cooling and dehumidifying, which is very useful in summer. However, in cold seasons, unless the windows fog up severely and quick dehumidification is needed, turning it on is purely a waste of fuel. Usually, I adjust the temperature control to a comfortable level and maintain good ventilation, which is sufficient. Once during a long trip, it was extremely cold and rainy, so I turned on the air conditioning to help defog the windows, making the interior feel drier and more comfortable. I suggest everyone pay attention to daily temperature settings to avoid blind operations that could affect fuel economy.

[LeCorey]

As someone with some knowledge of automotive technology, I'd say running the AC while using the heater in winter is unnecessary, though it can be considered under certain circumstances. In principle, the warm air comes from coolant heat exchange - turning on the fan delivers heat immediately. The AC compressor's cooling function is mainly for temperature reduction and dehumidification. Since winter air is naturally dry, using the AC not only wastes fuel but may also increase system load. However, if high humidity causes window fogging, activating the AC compressor can efficiently remove moisture and clear fog - this is a handy trick. Developing good habits like adjusting temperature before ventilation saves money and proves practical. I've personally saved on fuel costs during snowy conditions with good results.

[DeAlex]

When I first started driving, I was quite confused. In winter, I always turned on the AC when using the heater, thinking it would warm up faster. Later, I learned from an experienced friend that I was mistaken—the heater relies on the engine's natural heat, and turning on the AC compressor just wastes fuel. Now I understand: simply set the temperature to the red zone, turn on the fan, and the car warms up quickly. Occasionally, I use the AC for defogging to dehumidify. New drivers often make this mistake—I recommend observing the dashboard and adjusting as needed.