Should You Use Air Recirculation or Fresh Air Mode When Driving with AC on Rainy Days?

[AveryAnn]

It is better to use fresh air mode when driving with the air conditioning on rainy days. Here is the relevant information: Specific reasons: On rainy days when the weather is cold, both side windows tend to fog up, obstructing the driver's vision. Therefore, it is best to first use the fresh air mode and adjust the air vents to blow toward the windshield. Using fresh air mode helps expel the moisture exhaled by passengers out of the vehicle, while the outside cold air is less prone to condensation. Generally, when the windows are closed, air recirculation mode circulates the air inside the car through the blower. Since the passage for outside air is closed, no external air enters, making the air feel stuffy. In contrast, fresh air mode allows outside air to enter through the opened passage, keeping the air fresher. Precautions: When the outside air quality is poor or heavily polluted, such as on dusty roads, in congested traffic, or near chemical plants with strong odors, use air recirculation mode to prevent contaminated air from entering the car. During summer, to quickly cool down the interior with the air conditioning, air recirculation mode can be used.

[JosephFitz]

On rainy days when driving with the air conditioning on, I prefer to use the recirculation mode first. Because the outside humidity is high, if the external circulation is turned on, the smell of rain and damp air can easily enter the car, causing severe window fogging and affecting driving safety. I've driven many long distances in the rain and found that turning on the external circulation for a few minutes when first getting in the car to allow air to flow, then switching to recirculation mode along with the defogging button, can quickly clear the fog and maintain clear visibility. Recirculation also reduces the entry of outside air, allowing the air conditioning to maintain a comfortable temperature inside the car more efficiently and save energy. However, don't use recirculation mode all the time, as the air inside the car can become stuffy; after about half an hour, switch to external circulation for a few minutes to ventilate, then switch back. Alternating between the two modes ensures both safety and fresh, comfortable air quality, preventing dizziness or musty odors. In short, safe driving relies on good visibility, and using recirculation mode more often on rainy days is definitely the right choice.

[DiBrayden]

As a regular driver with kids in the family, I have to consider my children's comfort in the back seat when using the AC on rainy days. I usually start with the external air circulation to prevent them from feeling stuffy, but due to high humidity on rainy days, I quickly switch to internal circulation to prevent fogging. If the external circulation is left on for too long, the moisture from the rain can blur the windows and even bring in muddy smells from the road, affecting the family's comfort. Every time I get in the car, I first turn on the external circulation briefly for ventilation, then switch to internal circulation with the AC's dehumidification function—this solves the fogging issue and maintains a stable temperature inside. On long trips or during traffic jams, I turn on the external circulation every 20 minutes or so to refresh the air and avoid CO₂ buildup that could cause drowsiness. The key is ensuring the windows stay fog-free for clear visibility, keeping the whole family safe and at ease—no need to fuss over minor distractions. After driving in the rain, remember to clean the windows and vents, and during regular maintenance, check the AC filter to ensure efficient operation without issues.

[FernandoMarie]

With more driving experience, I directly turn on the air recirculation mode on rainy days. The outside air intake brings in rain moisture causing fogging, while using recirculation with the defroster solves it instantly. It maintains cabin temperature better, making it hassle-free and efficient. If the air gets stuffy, I briefly switch to fresh air mode for ventilation.

[ReaganRose]

From a technical perspective, the air recirculation mode seals the cabin air, while the fresh air mode introduces external moisture. Using fresh air mode on rainy days may increase the risk of fogging, whereas recirculation mode combined with dehumidification is more effective. It is recommended to briefly use fresh air mode for ventilation upon startup, then switch to recirculation to maintain comfort and safe visibility. If equipped with automatic climate control, the set temperature will intelligently adjust the mode.

[VonNolan]

Prioritizing environmental protection and energy efficiency, I prefer using the air conditioning in recirculation mode on rainy days. It reduces the entry of external heat and humidity, potentially easing the air conditioning load and saving fuel. However, prolonged use can deteriorate air quality, so it's advisable to alternate with fresh air mode for ventilation. Balancing comfort with safe visibility is key.