Does using air conditioning in a sedan consume more fuel?

[SanJeffrey]

Using the air conditioning for cooling in a car consumes more fuel, but using it for heating in winter does not. When the air conditioning is used for cooling, the air conditioning unit is in operation, powered by the car's engine, which increases the load and thus fuel consumption. However, using the air conditioning for heating in winter does not consume fuel. Here is more detailed information: Content 1: The warm air comes from the heat generated by the engine during operation. After the engine's cooling system dissipates heat from the engine, a fan directs this heat into the car's interior to create warm air. When the heating is not in use, the fan stops, and the heat vent closes, allowing the heat to dissipate completely into the atmosphere. Therefore, the car's heating system recycles waste heat and does not consume additional fuel. Content 2: The AC button controls the air conditioning compressor. In summer, when using the air conditioning, the AC button must be turned on to activate the cooling function. However, the heating system simply utilizes the internal heat cycle of the car and does not require the air conditioning compressor to be activated. Thus, to use the heating, you only need to adjust the air conditioning settings without turning on the AC switch.

[AniyahMarie]

Of course it consumes more fuel. I know this best after driving my small car for three years. When the air conditioning compressor starts, it consumes engine power, which is equivalent to adding extra load to the car. However, this depends on the situation. In city traffic jams, turning on the air conditioning can burn nearly 1 liter more fuel per 100 kilometers, which is particularly noticeable. But on the highway, where wind resistance increases, closing the windows and turning on the air conditioning is actually more fuel-efficient than opening the windows. Setting the temperature too low will keep the system running at high load, while setting it around 25 degrees is more economical. Turning on the air conditioning after warming up the car in the morning saves a bit more fuel than turning it on immediately after starting. Regularly replacing the air conditioning filter can also reduce the load a little, but it will always consume more fuel. Just accept it when it's hot.

[StLeonardo]

The core principle of air conditioning consuming fuel is that the compressor's operation requires engine power. Currently, the average compressor in household cars consumes 3-5 horsepower, equivalent to 10%-15% of the engine's output power. However, the actual increase in fuel consumption is not as severe, with a typical 1.6L car consuming only 0.7-1.2 liters more per 100 kilometers when the air conditioning is on. Hybrid vehicles have an advantage in this regard, as using an electric motor to drive the compressor is more energy-efficient. Older cars consume more fuel; if there are leaks in the air conditioning system, the cooling efficiency decreases, forcing the compressor to work longer. It is recommended to use ventilation mode more often during spring and autumn, and opening the external circulation to let in natural air can also be quite comfortable.

[Pat]

During the last maintenance, the technician told me that the air conditioning affects fuel consumption mainly in three aspects: first, continuous compressor operation consumes about 15% of the engine's power; second, low-temperature settings cause frequent compressor cycling, which actually consumes more energy; and third, dirty filters reduce cooling efficiency. He taught me a clever trick: after the car has been exposed to the sun, open the windows to ventilate for a few minutes before turning on the AC, and setting the temperature to 24°C with the fan on the second speed is the most economical. Now, using AC during summer commutes costs me an extra sixty to seventy yuan per month on gas, which is still much cheaper than taking taxis.