How Much Fuel Does Idling with Air Conditioning On Consume?
2 Answers
Idling with the air conditioning on for one hour consumes approximately 2.2406 liters of fuel. Automotive Air Conditioning Cycle Process: The compressor draws in low-temperature, low-pressure refrigerant gas from the evaporator outlet and compresses it into high-temperature, high-pressure gas, which is then discharged from the compressor. The high-temperature, high-pressure superheated refrigerant gas enters the condenser. The refrigerant liquid, now at higher temperature and pressure, passes through the expansion device, where its volume increases, and its pressure and temperature drop sharply, exiting the expansion device as a mist (fine droplets). During the evaporation process, it absorbs a significant amount of heat from the surroundings, after which the low-temperature, low-pressure refrigerant vapor re-enters the compressor. This process repeats continuously to achieve the goal of lowering the air temperature around the evaporator. Fuel Consumption When Idling with Air Conditioning On: Because the movement of the air conditioning compressor relies on the engine for power, even at idle, the engine continuously burns gasoline. Additionally, engine carbon buildup also affects fuel consumption, meaning older cars tend to consume more fuel over time. Furthermore, the quality of gasoline is a key factor influencing fuel consumption. If dirty gasoline from small gas stations is used, such gasoline contains many impurities when burned, not only worsening engine carbon buildup but also leading to incomplete combustion, requiring more fuel to achieve the desired output, thus consuming fuel more quickly.
I used to often shift to neutral and turn on the AC to cool down while waiting at red lights, especially during hot summers. It was indeed very convenient, but it significantly increased fuel consumption. Take my compact car as an example: idling with the AC on consumes about 1.5 to 2 liters of fuel per hour, depending on the vehicle size and AC cooling intensity. For larger SUVs or older cars, it can exceed 2.5 liters. This translates to an extra 12 to 20 yuan per hour in fuel costs—quite a substantial expense. Doing this long-term not only wastes fuel but also increases engine load, potentially accelerating part wear. I recommend avoiding it or limiting it to under 10 minutes. Instead, use ventilation mode while driving or park in shaded areas to save fuel, which is also more environmentally friendly.
