Does Using Air Conditioning on Highways Consume More Fuel?
3 Answers
Using air conditioning definitely consumes more fuel than not using it. There is not much difference in fuel consumption between using air conditioning on highways and regular roads. When driving on highways, it is recommended to use the air conditioning in external circulation mode. There are two main reasons for using external circulation on highways. Highway: When driving on highways, the windows are usually closed, preventing air circulation inside the vehicle. Turning on external circulation allows outside air to enter the car, improving the freshness of the air inside. Air Conditioning: During high-speed driving, external circulation has little impact on the effectiveness of the air conditioning. The weakening effect of using external circulation during normal air conditioning use is minimal. Windows: Fogging on the windshield is mainly caused by high humidity inside the car. Turning on external circulation continuously replenishes fresh air, maintaining moderate humidity inside the car and reducing the likelihood of fogging.
Running the AC while driving on the highway definitely increases fuel consumption, which I've personally experienced. This is because the AC compressor is connected to the engine belt, requiring the engine to exert extra effort to power it, naturally leading to higher fuel consumption. Specifically, my car's fuel consumption is around 7 liters per 100 kilometers without AC, but it can rise to 7.5 or even 8 liters with the AC on, which translates to roughly an additional 10% fuel consumption on highways. At a steady speed of about 100 km/h on the highway, the engine operates efficiently, and the AC load proportion is relatively smaller compared to city driving in traffic jams, where it can increase consumption by over 20%. The type of AC also matters—automatic AC is more intelligent than manual, adjusting based on temperature to avoid waste. Driving with windows open at speeds over 80 km/h increases air resistance, making it even less fuel-efficient, so using the AC wisely is a practical solution. I believe the extra fuel cost for comfort is worth it, but regular maintenance of the AC system, such as cleaning the filter, can reduce the load.
I've been driving on highways for decades, and experience tells me that using the AC increases fuel consumption. Actual tests show that driving on the highway in summer with the AC on raises the fuel consumption from 6 liters per 100 km to around 6.8 liters, which only amounts to a few extra dollars in fuel costs. However, on the highway, the speed is more consistent, and the engine load is lighter, so the extra fuel used by the AC isn't as noticeable as in city traffic with frequent stops. At higher speeds, opening the windows creates loud wind noise and increases drag, sometimes even consuming more fuel than using the AC. So, I usually keep the windows closed and use the AC, setting the temperature to 22°C with automatic fan speed, and the compressor doesn't run at full speed to save energy. The comfort improvement is significant, and safe driving is more important. The impact on fuel consumption is negligible in the long run, so I recommend beginners not to overthink it and use automatic modes to reduce extra load.
