Should You Use the External Air Circulation When Running the Car AC in Summer?

[VonLondyn]

You should use the external air circulation when running the car AC in summer. The correct way to turn on the car AC in summer is: first turn on the external air circulation to expel the hot air inside the car. After feeling a significant drop in the cabin temperature, you can then switch to internal air circulation. Internal Air Circulation System: The air exchange channel between the inside and outside of the car is closed. When the fan is off, the airflow inside the car does not circulate. When the fan is on, the inhaled airflow comes only from inside the car, forming an internal airflow circulation. External Air Circulation System: The external air circulation mode uses the fan to draw air from outside the car into the cabin. The air blown by the fan comes from outside the car. Even if the fan is off, airflow is still drawn into the car while driving, replenishing fresh air inside the car.

[AliceMarie]

Should you use the air recirculation mode when running the car AC in summer? After driving for over a decade, I believe this depends on the situation. When it's extremely hot initially, I definitely turn off the fresh air intake and use recirculation mode first. This allows the car's interior air to be repeatedly cooled, making the AC more powerful, cooling the cabin faster, and saving some fuel. Once it cools down—say after 15 minutes or when feeling slightly stuffy—I switch to fresh air mode for a few minutes to let in some outside air and prevent dizziness. However, summer street air tends to be polluted, especially during traffic jams or while waiting at red lights. In these cases, using fresh air mode might draw in exhaust fumes, so I generally avoid it and stick with recirculation for safety. Overall, recirculation mode is my go-to—convenient and efficient. Just remember to replace the cabin air filter regularly, otherwise ventilation won't be clean anyway.

[ArielDella]

My driving habit in summer is to minimize the use of the external air circulation when the AC is on. When the car gets hot, turning on the external circulation brings in hot air from outside, making the AC work harder to cool down and increasing fuel consumption, which isn't cost-effective. So, I use the internal circulation to cool down quickly and save energy. However, keeping it closed for too long can make the air inside stale and uncomfortable to breathe, so once it's cool enough, I briefly switch to external circulation for ventilation or open the windows in an area with fresh air. In the city, where there's more exhaust fumes, I avoid using external circulation even more; on the highway, I might use it a bit more for better air flow. In short, prioritizing energy efficiency and comfort, I prefer the internal circulation.

[StJayce]

In summer when using the air conditioning, I usually turn off the external air circulation. When first getting into a hot car, turning on internal circulation makes the AC blow cooler air much faster, instantly cooling down the car. When feeling stuffy after prolonged use, I briefly switch to external circulation for a few minutes to ventilate. But since hot outside air makes the AC work harder in summer, I only use external circulation when necessary. During urban traffic jams, external circulation easily draws in exhaust fumes, so it's safer to use it sparingly. Overall, internal circulation is simpler and more worry-free.

[DelBentley]

As a daily commuter, I always use the air recirculation mode when running the AC in summer. When getting into a scorching hot car, turning on recirculation provides instant and efficient cooling - the temperature drops quickly while saving fuel. However, prolonged use makes cabin air stale, so I briefly switch to fresh air mode for ventilation. But outside heat and pollution strain the AC system, especially during urban traffic jams, making it less safe. Therefore, I primarily use recirculation mode, combined with periodic window opening or cabin filter replacement, to maintain healthy breathing. This method is both energy-efficient and practical.