Should the Air Conditioning Use Internal or External Circulation on the Highway?

[VonHailey]

On the highway, it is recommended to use the external circulation mode for the air conditioning, which utilizes the outside air and exchanges it with the interior air through the compressor. The correct method for using car air conditioning is as follows: 1. Turn on the AC switch; 2. Adjust the air vent selector knob—direct the vents upward when cooling and downward when heating; 3. Adjust the fan speed control; 4. Switch between internal and external air circulation; 5. Adjust the temperature control knob. Car air conditioning is a system designed to cool, heat, ventilate, and purify the air inside the vehicle. Maintenance tips for car air conditioning include: 1. Regularly clean the air vents; 2. Maintain the condenser in a timely manner; 3. Clean or replace the air filter as needed.

[VonEloise]

When driving on the highway, I prefer using the air recirculation mode to control the AC, as it cools the cabin faster and reduces fuel consumption. At high speeds, using the fresh air mode can draw in dust and exhaust fumes from outside, affecting the air quality inside the car. Especially during long summer drives with the AC on, recirculation mode lightens the load on the AC system, saving some fuel costs. However, I've noticed that prolonged use of recirculation can make the air stale. Once, after four hours of driving, the buildup of carbon dioxide in the cabin made me drowsy, which was quite dangerous. So, I recommend switching to fresh air mode for a few minutes every 30 to 40 minutes to ventilate the cabin, especially using recirculation mode for protection when passing through tunnels or heavily polluted areas. The key to safe driving is staying alert and comfortable. If the car has an automatic mode, enabling it allows the system to switch intelligently for better results.

[LeNaomi]

As an energy-conscious driver, I prioritize using recirculation mode on highways to optimize fuel efficiency. Recirculation utilizes the cabin's existing air, eliminating the AC's need to cool hot outside air, which reduces engine load and saves 5-10% fuel per 100km—more environmentally friendly. Studies confirm this: high-speed winds increase aerodynamic drag with fresh air intake, raising fuel consumption. But don't focus solely on savings; I once forgot to ventilate, causing dizziness from oxygen depletion. Now, I briefly switch to fresh air mode hourly, timing it with cleaner-air sections—balancing efficiency and health. For long highway drives, comfort is key to preventing fatigue, a tip novice drivers might find helpful.

[VanKate]

When driving at high speeds, I find the recirculation mode more convenient and practical. It cools down faster without waiting for the AC to cool down the hot external air, which starts slowly. In fresh air mode, at high speeds, dust or road odors can easily enter, making cabin cleaning troublesome. Every time I travel, I first use recirculation for ten minutes to cool down, then switch to fresh air briefly for ventilation—simple and effortless. If someone smokes in the car or when passing through industrial areas, keeping recirculation on helps avoid pollution. Related tip: Switching to fresh air when windows fog up aids in dehumidification and prevents fogging for safer driving. This experience has helped me avoid many hassles.