What is the difference between AC and AUTO in car air conditioning?

[LailaLynn]

The differences between AUTO and AC in car air conditioning: 1. Different working principles: AC is the switch for the air conditioning compressor. Only when AC is turned on will the compressor work, providing cooling and dehumidification; AUTO is the automatic air conditioning switch. Once the temperature is set, the air conditioning system will automatically control the compressor and airflow to maintain the set temperature. 2. Different fuel consumption: When the AC light is on, the air conditioning compressor starts, increasing the engine load and consequently fuel consumption; AUTO car air conditioning for heating is not related to the compressor. The heat source for heating comes from the engine's heat, provided by the car's radiator, and then blown into the cabin by the blower, with almost no impact on fuel consumption. 3. Different usage methods: In summer, when using the air conditioning, turn on the AC button to start the compressor inside the car, allowing cold air to be blown out. In winter, when heating is needed, there is no need to turn on AC, as AC does not help with heating at all. Simply turn on AUTO to get heating.

[StAdriana]

The difference between AC and Auto in air conditioning is quite interesting. The AC button is a manual switch for activating the air conditioning compressor, specifically responsible for cooling; when you press it, the compressor immediately starts working, blowing cold air to lower the temperature. Auto mode, on the other hand, is the automatic control function of the entire air conditioning system; you just need to set the target temperature, and the system intelligently adjusts the fan speed, airflow direction, and automatically decides when to turn the AC compressor on or off. For example, on a hot summer day, pressing Auto and setting it to 22°C will make the car quickly activate the AC and increase the fan speed to blow cold air; setting it to 28°C might only produce warm air to save energy. The technology behind this involves sensors that monitor the interior temperature in real-time, making driving more effortless and efficient. I prefer Auto because it's fully automated, but AC is more direct when rapid cooling is needed.

[SanAna]

In daily driving, I've tried two modes. AC is a simple switch: turning it on immediately cools, ideal for quickly lowering the temperature after summer sun exposure. Auto mode acts like a little assistant, automatically adjusting fan speed and turning AC on/off after setting the temperature. For example, it activates AC with strong airflow when set to low temperatures on hot days, and provides warm air without manual fan adjustments when set to high temperatures on cold days. The biggest difference lies in the level of automation; AC requires frequent adjustments to fan speed or temperature, while Auto is more convenient as it's set and forgotten. For average car owners, Auto offers convenience and comfort, but AC responds faster when immediate cooling is needed. It's recommended to choose flexibly based on weather: use Auto for automatic warm air in winter and spring, and manually control AC for cooling during scorching summers.

[McRebecca]

From an energy consumption perspective, the difference is significant. The AC button keeps the compressor running continuously, consuming fuel as the cooling process requires extra engine power. Auto mode intelligently optimizes by only activating AC when cooling is detected as necessary, such as automatically reducing fan speed after reaching the set temperature to avoid waste. Using Auto can save approximately 10-15% fuel, especially in urban traffic where frequent compressor cycling consumes more energy; manual AC operation often leads to excessive cooling waste. As a fuel-saving enthusiast, I prefer Auto mode to let the system operate efficiently and protect the environment.