What is the difference in fuel consumption between setting the car air conditioner to the first gear and the second gear?
3 Answers
There is basically little difference in fuel consumption between the first gear and the fourth gear or other gears of the car air conditioner, which can be ignored. Specific differences: 1. Different speeds: Because the difference in blower speed brings a very small difference in engine load, the difference in fuel consumption can be basically ignored. 2. Using automatic mode: When the air conditioning system is working, the fuel consumption is related to the engine load, but the engine load when the air conditioner is turned on depends on the expected temperature adjusted by the driver. 3. Not using automatic mode: There will be a significant difference in engine fuel consumption.
Having driven for over a decade, from old gasoline cars to new hybrids, I've noticed that when the AC is set to the second level, the higher fan speed and greater cooling demand require the compressor to work faster, which draws more power from the engine, inevitably increasing fuel consumption compared to the first level. On average, in city traffic, using the second level can burn about 0.5 liters more per 100 kilometers. The first level, with its lower fan speed, puts less load on the compressor, saving fuel. Newer cars have smarter AC systems, reducing the difference once the temperature stabilizes, but sticking to the first level still helps save money and reduce emissions—that's how I always set mine. On highways, where wind resistance compensates for the AC's impact, the difference between levels might be less than 0.2 liters, but over time, the fuel-saving effect becomes noticeable.
I often drive long distances and always notice the fuel gauge changes when turning on the AC: setting it to the higher fan speed means the compressor works harder, the engine exerts extra effort, and naturally consumes more fuel. Switching to the second fan speed can increase fuel consumption by 0.3 to 0.8 liters per 100 kilometers, depending on the car's age. Using the first fan speed reduces the compressor load and saves fuel. I remember this difference is especially noticeable during summer heat—stop-and-go city driving with the second fan speed makes refueling more frequent. My suggestion is to start with the first fan speed on hot days to let it cool down gradually, avoiding the rush to the second speed which burns more fuel. Some automatic AC models can even adjust fan speed automatically to minimize waste. Now, my car is set to prioritize strong airflow without fussing over speed settings, making daily driving more fuel-efficient and hassle-free.
