What does AC in the air conditioner mean?

[DelArabella]

AC in the air conditioner refers to the cooling switch of the car air conditioning system. Pressing the AC button will gradually lower the temperature inside the vehicle. The car air conditioning refrigeration system consists of components such as the compressor, condenser, receiver-drier, expansion valve, evaporator, and blower, all connected by copper pipes and high-pressure rubber hoses to form a sealed system. The car air conditioning system can cool, heat, ventilate, and purify the air inside the cabin, providing a comfortable environment for passengers and reducing driver fatigue, thereby enhancing driving safety. It generally includes refrigeration devices, heating devices, and ventilation systems.

[LaIris]

AC stands for Air Conditioning compressor, that button with the snowflake icon on your car's dashboard is it. Back when I drove my old car, I never quite understood it until a mechanic explained that this thing works like the heart of a refrigerator—cold air only blows when you press it. Once activated, it absorbs the hot air inside the car and recirculates it as cool air. So in summer, always press AC for cooling, otherwise, the air blowing is just at ambient temperature. But in winter, there's no need to press AC for heating since the warm air is drawn directly from the engine's heat—using AC would only waste fuel and cool the air. Also, don’t confuse it with the car’s air recirculation function; these two features operate separately.

[WyattLee]

I've noticed many new drivers are confused about the AC button - simply put, it's the cooling switch. During my road trip last year when temperatures hit 42°C, I couldn't get cool no matter how long I drove with windows down, until I finally remembered I hadn't pressed the AC button. When activated, you'll hear a 'click' from the engine bay - that's actually the electromagnetic clutch engaging. I remember when I first started driving, I turned on AC during winter and ended up with completely fogged windshield. Now I understand: pressing AC accelerates dehumidification when defogging, but you don't need it for winter heating - it wastes fuel and causes temperature fluctuations. For best cooling effect, use AC with recirculation mode, then switch to fresh air mode on highways for ventilation.

[IslaFitz]

People often ask what the AC button is for—it's simply the cooling switch. The principle is similar to that of a home air conditioner: when pressed, the compressor starts up, compressing the refrigerant into a liquid. This liquid then passes through the mesh-like condenser at the front of the car to dissipate heat before being sent to the small radiator inside the dashboard, where it rapidly expands and cools down. Finally, the blower blows air over it, producing cold air. A key point to note is that the AC light must be on to indicate the cooling function is active, especially when first getting into the car on a hot summer day—it's best to open the windows to let out the hot air before turning on the AC. In autumn, using the AC alongside the heater can also enhance defogging effectiveness. Avoid keeping the compressor running unnecessarily, as this can strain the vehicle.