How much fuel does a car consume when running the air conditioning for an hour without turning off the engine?
3 Answers
This varies slightly depending on the vehicle model, but for most family cars, it typically ranges between 1L to 3L of fuel per hour. Here are some relevant details: 1. Damage to the car: Instead of focusing on the economic cost of fuel consumption when idling with the air conditioning on, more attention should be paid to the potential damage to the car and the resulting increased maintenance costs. When the engine runs at low RPMs in idle mode for extended periods, it is more prone to carbon buildup on the pistons and valves. Excessive carbon deposits can directly affect fuel efficiency and may also impact the engine's performance and even its lifespan. 2. Carbon monoxide: Since the air inside the car cannot circulate, if carbon monoxide from the engine leaks into the cabin, it can gradually accumulate and reach dangerous concentrations, leading to poisoning. There have been many cases where people fell asleep and never woke up due to this issue.
I've had several experiences of parking by the roadside with the air conditioning on during summer, and the fuel consumption per hour was really not insignificant. Take my 1.8L sedan as an example: idling without AC consumes about 0.8 liters of fuel, but with AC on, it rises to around 1.2 liters due to the additional load from the compressor and fans. During a recent test on an extremely hot day, the fuel consumption almost jumped to 1.5 liters, equivalent to half a tank gone. A friend driving an SUV had an even more dramatic situation, consuming nearly 2 liters per hour. This can be affected by the vehicle's age and temperature—older cars or extreme heat make the AC guzzle more fuel. Calculated, it costs 15 to 30 yuan in fuel, comparable to the waste from half an hour of traffic congestion. I usually try to avoid this—it's both expensive and environmentally unfriendly.
When a car is idling, although the engine is not moving, it still requires fuel supply to maintain operation. After turning on the air conditioning, the compressor activates, increasing the engine load by 20% to 40%, which leads to higher fuel consumption. Taking a typical family sedan as an example, with an engine displacement of 1.5 to 2.0 liters, idling for one hour without air conditioning consumes 0.7 to 1.0 liters of fuel, but with air conditioning on, this can rise to around 1.0 to 1.6 liters. Smaller cars consume less, while larger cars consume more, depending on the compressor's power and the ambient temperature. The hotter the weather, the lower the air conditioning efficiency, potentially increasing fuel consumption to up to 2 liters. I recommend checking the vehicle's manual for reference values, but an average of 1.2 liters per hour is a common range. Avoiding prolonged idling can save fuel and protect the engine.
