Do I need to turn on the AC when using the car heater?
3 Answers
You don't need to press the AC button when using the heater. Here's some relevant knowledge about the AC button: Function: The AC button is used for air conditioning adjustment. You can press it when using the cold air function, as this activates the air conditioning compressor for cooling. However, it's not recommended to press this button when using the heater, as it doesn't engage the air conditioning compressor for heating. Principle of car heater operation: The heater utilizes heat generated by the engine during operation: After the engine's cooling system dissipates heat from the engine, a fan directs this dissipated heat into the car interior, creating warm air.
When driving in winter, I usually use the heater to keep warm and generally don't turn on the AC. The heating system utilizes waste heat generated by the engine to warm the air, which doesn't consume extra fuel or add additional load, making it very efficient. Turning on the AC activates the compressor for cooling and dehumidification, which increases fuel consumption and may also put extra load on the engine, affecting performance. Unless the windows fog up or the air is very humid, there's no need to use the AC for dehumidification to quickly clear fog and ensure driving safety. In dry weather, it's completely unnecessary to use the AC, which can save some fuel costs and contribute to environmental protection. Many cars have an automatic mode, but I prefer manual adjustments to avoid unnecessary operations. Remember, using the AC with the heater is an exception, not the norm—keeping it simple is best for handling various climate conditions.
After driving for many years, I've concluded that you generally don't need to turn on the AC when using the heater. The heater utilizes engine heat for warmth, while the AC is specifically designed for cooling—activating it consumes additional fuel and increases overall fuel costs. During everyday driving, you should only consider using the AC's dehumidification function when encountering foggy conditions or high humidity that causes window fogging, as it helps restore visibility faster and prevents hazards. Modern vehicle air conditioning systems are intelligently designed, and most will default to turning off the AC when heating to save energy. However, if the driver manually operates it, they should pay attention to the situation. From an experiential perspective, using the AC less can extend the lifespan of car components and reduce maintenance frequency—developing good habits is crucial.
