How much fuel does a car consume with the AC on at idle for one hour?
2 Answers
1. Approximately 1 liter of fuel is consumed per hour. Additional extended information is as follows: 1. Introduction: The air conditioning compressor is directly driven by the engine crankshaft, and the power is transmitted between the compressor pulley and the compressor drive shaft via an electromagnetic clutch. After pressing the A/C switch, when the cabin temperature is higher than the set temperature, the electromagnetic clutch engages, and the compressor starts working. When the cabin temperature is lower than the set temperature, the clutch disengages, and the compressor stops working. 2. Calculating only the fuel consumed by the air conditioning: The fuel consumption rate of the engine at idle is generally about 400 grams per kilowatt-hour. Assuming the average power consumption of the air conditioning is 2 kilowatts per hour, the additional fuel consumption for running the AC for one hour would be 400×2=800 (grams). The density of gasoline is 750 grams per liter. Therefore, a 2-kilowatt air conditioning system consumes approximately 1.07 liters of fuel per hour.
The fuel consumption of idling a car with AC on for an hour varies greatly depending on the vehicle model and condition. For small-displacement cars like 1.5L family sedans, I estimate it burns 1 to 1.5 liters per hour, roughly equivalent to over ten yuan. Larger vehicles such as SUVs or pickups with bigger engines and heavier loads may consume 1.5 to 2 liters or more. The AC's power significantly impacts consumption—running at maximum cooling in summer increases drag on the compressor, forcing the engine to work harder and burn more fuel. Older or poorly maintained cars are even thirstier due to carbon buildup clogging fuel lines. To save fuel, avoid prolonged idling with AC; instead, turn off the engine and open windows for ventilation or park in shaded areas. Using a mobile app to track fuel gauge changes for simple calculations is ideal—developing this habit saves money and protects the engine long-term.
