Does Running the AC Without Driving Consume Fuel?
2 Answers
Yes, it consumes fuel. When a car runs the air conditioning while driving, it uses approximately 20% of the engine's power. Additional information: Reasons for high fuel consumption in cars: 1. Aging spark plugs: Spark plugs are essential for igniting the air-fuel mixture in the cylinders. Poor performance or aging of spark plugs will inevitably lead to engine fatigue and increased fuel consumption. 2. Rapid acceleration: Quick acceleration while driving causes strong friction between the tires and the ground, accelerating tire wear and increasing fuel consumption. 3. Long periods of idling without turning off the engine: Compared to normal driving, when the car is idling or just started, the engine ECU controls a higher amount of fuel injection. If the engine is not turned off or frequently idles for long periods, fuel consumption will increase.
I think this issue is quite important because I remember one time waiting in the car during summer with the AC on but the engine off, and the fuel gauge dropped much faster than usual. Later, I realized that the car's AC compressor is driven by the engine—if the engine isn't running, the compressor doesn't work. However, when the ignition is on (standby mode) and the AC is activated, the engine idles to generate power for the compressor, which consumes fuel. For a typical sedan, idling with the AC on can burn an extra 0.5 to 1 liter of fuel per hour—essentially wasting money and increasing emissions. My advice is to avoid sitting in the car for long periods with the AC running. If you need to cool down, park in the shade, roll down the windows for ventilation, or step out for a walk. Frequent engine idling also shortens component lifespan and raises maintenance costs, making this practice economically and environmentally unwise.
