Should You Use External or Internal Air Circulation for Car AC on Rainy Days?
2 Answers
It is better to use external air circulation for your car on rainy days. Here is the relevant information: External Circulation: External circulation mode uses a fan to draw outside air into the car, meaning the air passages between the outside and inside of the car are open. The air blown by the fan comes from outside, and even if the fan is off, airflow is still drawn into the car while driving, replenishing fresh air inside. Sometimes, you may feel airflow even when the fan is off, which is due to the external circulation setting. When driving in congested urban areas, the car may fill with exhaust fumes, which is caused by using external circulation. Location: The external circulation air intake for the AC is located below the windshield wiper blades. Turning on external circulation allows outside air to enter the car as cooled or heated air, generally used when outdoor air quality is good. Internal circulation, on the other hand, recirculates the air inside the car for cooling or heating without letting outside air in, typically used when outdoor air quality is poor. However, it is not advisable to use internal circulation for extended periods, as this prevents air renewal inside the car, potentially affecting health.
Driving on rainy days, the car windows are most prone to fogging up. Having driven for so many years, I know this is very dangerous. So first, use the external air circulation—it quickly blows away the damp, cold air, which is very effective for defogging. Once the fog lessens, switch to internal air circulation to retain warmth and prevent the car’s temperature from dropping too quickly. Don’t set the air conditioning too low; around 20 degrees Celsius is just right. If you don’t defog in time, the blurred vision can easily lead to accidents. Car enthusiast groups have shared that continuous external air circulation is good for defogging in the rain, but don’t use it for too long. A little extra fuel consumption is nothing compared to safety first.
