Should the Car's Cold Air Use External or Internal Circulation?
2 Answers
Both internal and external circulation can be used when turning on the car's cold air. There is no strict requirement, and the best practice is to alternate between internal and external circulation. Here are some precautions for using the car's cold air: 1. The correct way to use cold air in summer. After getting in the car, first open the windows for ventilation to allow the interior to cool down. Open the doors and windows to lower the temperature inside the car before turning on the air conditioning. Start with internal circulation to cool down the car as quickly as possible. Once the interior temperature reaches a comfortable level, switch to external circulation to maintain fresh air inside the car, except on smoggy days. 2. Avoid rushing to use internal circulation in summer. On hot summer days, many people immediately turn on internal circulation upon entering the car, thinking it will cool the interior faster. However, the opposite is true. In summer, the temperature inside the car is often higher than outside, and using internal circulation actually slows down the cooling process.
When using the car's air conditioning, whether to choose recirculation or fresh air mode, I'd like to share my experience. On hot summer days after starting the AC, I usually begin with recirculation mode first—it cools the hot air inside the car rapidly because recirculating the same air makes cooling highly efficient. Within a minute or two, the cabin becomes comfortably cool. Once the temperature drops, I switch to fresh air mode to let in outside air and prevent the interior from becoming stale during prolonged recirculation. For instance, after about an hour of driving with continuous recirculation, CO₂ buildup can cause fatigue. This is especially effective for reducing fogging risks when external air quality is poor. Adjusting appropriately during rainy days or poor air quality is crucial. Developing this habit helps maintain a comfortable balance while driving.
