Why are there water droplets at the car's air conditioning vents?
3 Answers
The reasons for water droplets at the car's air conditioning vents are as follows: Air conditioning set too low: When the air conditioning is set too low, moisture in the air can condense on the outside of the vents, creating a white mist effect. The moisture can also condense on the plastic casing of the evaporator or the surface of the plastic ducts delivering cold air, leading to dripping. Evaporator: This situation is more likely to occur in vehicles with poor insulation on the plastic casing of the evaporator or the plastic ducts delivering cold air. Poor vehicle sealing: High-humidity outside air continuously leaks into the car interior. Another typical symptom of excessively high humidity inside the car is the condensation of water droplets around the vents.
I also encountered water dripping from the air vents last time. It's mainly due to the large temperature difference between the inside and outside of the car, especially in summer when it's scorching hot outside and the air conditioning is set very cold inside. At this time, moisture in the air condenses into water droplets at the vents, just like water droplets forming on the outside of an ice-cold soda bottle. Another possibility is a clogged drain pipe, where the condensed water from the air conditioner's evaporator can't drain properly and flows back into the cabin. I suggest first trying to increase the air conditioning temperature or switch to recirculation mode. If that doesn't work, then it's necessary to check the drain pipe and clear any blockages.
Having driven for twenty years, I've seen plenty of cases where water droplets form at the air vents. Usually, it's because the air conditioning is cranked up too high, causing condensation to flow where it shouldn't. Additionally, if the air filter hasn't been changed for too long, dust buildup can block the air ducts, trapping moisture inside. If you notice a musty smell, be extra cautious—it could mean the evaporator core is dirty and holding stagnant water. My advice is to check if the drainage pipe outlet is clogged with sludge; it's usually located under the chassis—just use a thin wire to clear it out. If that doesn’t work, you might need to disassemble and clean the evaporator core, which won’t cost much.
