Should the car AC be turned on in winter?
3 Answers
When using the car's air conditioning in winter, there is no need to turn on the AC switch. The AC switch is required when turning on the cold air in summer, and turning on the AC switch will consume a certain amount of fuel. When using the heater, the air conditioning compressor is not involved; the blower simply directs some of the engine's heat into the car, and it does not consume any fuel. If the AC button is pressed while using the air conditioning in winter, although it will not affect the heating function, it will prolong the time it takes for the engine's water temperature to rise and increase the car's fuel consumption. However, if fog appears on the car windows when the heater is turned on in winter, the AC switch must be turned on to defog the windows quickly.
I've been driving for over twenty years, and in winter when using the air conditioning, you generally don't need to turn on the AC switch because the AC is mainly for the compressor's cooling function. In winter, heating primarily relies on the warm air from the blower. However, if you want to prevent the windows from fogging up, you'll need to turn on the AC. Although warm air is hot, it increases the humidity inside the car, causing the windows to fog up and obstructing your view of the road, which is dangerous. I recommend starting by setting the air conditioning to warm air mode when you start the car, then pressing the AC button briefly to dehumidify. Most new cars are designed to handle this automatically in AUTO mode—you just need to set the temperature. In winter, the air is dry, and fogging often occurs, especially during rain or snow. Developing this habit can save you from last-minute panic. Don’t forget to regularly check the air filter to keep the airflow smooth, which can extend the system's lifespan. Safety comes first—don’t skip defogging just to save a bit of fuel.
We often take family trips, and in winter, we turn on the car's AC for heating. However, it's annoying when the rear windows keep fogging up with the kids sitting in the back. In this case, we need to turn on the AC for dehumidification—just press that air conditioning button to get it done. The warm air only heats the air; without the AC, the humidity will increase, and the fog will get worse, affecting driving visibility. Once, I almost had an accident because I didn’t notice it in time. Some people worry that the AC consumes too much fuel, but in reality, you only need to turn it on briefly for defogging. Safety is far more important than fuel costs. Most modern cars have smart settings—just press the AUTO button, and the system automatically balances temperature and dehumidification. That’s how we operate our family car—it’s hassle-free and effective. Regular maintenance of the AC filter can also prevent odors and ensure fresh air. Safety on the road is the top priority, and using the AC functions correctly ensures peace of mind for the family.
