Which consumes more fuel on the highway: opening windows or using air conditioning?
2 Answers
On the highway, at 70 km/h, the fuel consumption between opening windows and using air conditioning is the closest. Below 70 km/h, opening windows saves slightly more fuel, while above 70 km/h, opening windows consumes more fuel. Reasons for higher fuel consumption with air conditioning: Setting the air conditioning to 25 degrees Celsius is most suitable in summer. One major reason for high fuel consumption in cars during summer is the excessive use of air conditioning. Therefore, reducing the fuel consumption caused by air conditioning will lower the vehicle's overall fuel consumption. Some car owners set the air conditioning to the lowest temperature to keep the interior cooler. However, this causes the air conditioning pump to run continuously and the blower to operate at high speed, which actually increases fuel consumption. Additionally, a large temperature difference between the inside and outside of the car can make people more prone to catching a cold. Methods to save fuel with air conditioning: Experts suggest opening windows before turning on the air conditioning. Using air conditioning for extended periods increases engine load and fuel consumption. After entering the car, owners should first open the windows to let out the hot air inside, then turn on the air conditioning. It's also recommended to periodically adjust the air conditioning settings and avoid keeping it on high speed all the time.
As an experienced driver with decades of driving experience, I've found that opening windows at high speeds actually increases fuel consumption. This is because car designs account for aerodynamics—once windows are opened, airflow rushing into the cabin acts like adding a large drag bucket, significantly increasing wind resistance. The engine then has to work harder to maintain speed, naturally leading to higher fuel consumption. Test data shows that at speeds over 100 km/h, open windows can increase gasoline usage by up to 20%, whereas using air conditioning, despite the compressor adding engine load, only raises consumption by about 10-15%. Therefore, to save fuel while avoiding wind noise, I always opt for air conditioning. This habit makes long-distance driving more comfortable and relaxed for me, without extra fuel costs.
