Car AC systems use the engine to operate, which means they indirectly consume fuel. When you turn on the AC, the engine has to work harder to power the compressor that cools the air. This increased load on the engine leads to higher fuel consumption. In contrast, while the car is running, the battery gets recharged by the engine’s alternator, but the AC itself doesn’t directly use battery power.

Yes, a car’s AC system does consume fuel. When you use the air conditioning, the engine needs to work harder to power the AC compressor. This additional workload increases fuel consumption because the engine has to burn more fuel to maintain the same level of performance while running the AC. The effect on fuel efficiency can vary depending on the vehicle and how much the AC is used.

When the car is parked and the engine is running, such as when idling with the AC on, it still consumes fuel, although the amount is relatively small compared to driving. The exact fuel consumption can vary based on the vehicle’s engine size, the efficiency of the AC system, and other factors. Generally, idling with the AC on might consume around 0.2 to 0.5 liters of fuel per hour, but this is a rough estimate and can differ between cars.

For a more accurate figure, you might want to check your vehicle’s manual or consult the manufacturer.

Not using the AC can improve fuel efficiency, but the exact amount saved depends on various factors, including the vehicle type, driving conditions, and the efficiency of the AC system. On average, not using the AC can save about 5-10% of fuel, especially in city driving where the AC load has a more noticeable impact. In highway driving, the effect of not using AC is less pronounced, as the drag from open windows can sometimes offset the savings from turning off the AC.