Should You Turn on AC When Using Car Heater in Winter?
2 Answers
In winter, you should not turn on the AC when using the car heater because the AC switch is the cooling switch for the car's air conditioning system. When the AC switch is turned on, the car's air conditioning compressor starts working. Although the cooling effect of the compressor is not obvious in low temperatures, it can still cause damage to the compressor. The AC button stands for Airconditioning. Pressing this button in summer activates the compressor of the air conditioner, starting the cooling process, which makes the air inside the car cooler. However, in winter, there is no need to press the AC button because the air conditioning system does not require the compressor. Instead, it simply transfers the heat from the engine into the car to raise the interior temperature. How to use the car air conditioner in winter: Start the engine to warm it up, wait until the engine coolant temperature reaches above 40 degrees Celsius, then turn on the heater, switch to external air circulation to expel the cold air from the car, and finally switch to internal air circulation. How the car air conditioner heating works: When the engine coolant becomes sufficiently hot, the refrigerant gas enters the condenser, where its pressure and temperature decrease, causing the refrigerant gas to condense into a liquid and release heat.
I usually drive to and from work, and I've noticed that in winter, I don't really need to turn on the AC when using the heater unless the air is particularly humid and the windows fog up. The AC function involves the air conditioning compressor, which increases engine load and leads to higher fuel consumption. The heater itself relies on the engine's residual heat and doesn't consume extra fuel, making it both economical and fuel-efficient. The benefit of using the AC is that it dehumidifies and prevents fogging—just press it when visibility is poor on foggy days, and your view will clear up immediately, putting safety first. Cars with automatic climate control may activate the AC for dehumidification automatically, so it's best to manually turn it off to save money. It's recommended to use the recirculation mode in combination, bringing in dry air to reduce the need for defogging, so you can usually keep the AC off for better fuel efficiency. For maintenance, regularly clean the cabin air filter to ensure the system runs efficiently and avoid unnecessary wear.
