Should You Turn Off the Air Conditioning When Exiting the Car?

[LaOlive]

You should turn off the air conditioning when exiting the car. Here are the reasons why you should turn off the air conditioning when exiting the car: Reason 1: After the engine is turned off, it cannot drive the compressor, so the air conditioning cannot provide cooling. Keeping the air conditioning on after turning off the engine will reduce the battery's lifespan. Reason 2: The air conditioning increases the load when starting the car. Reason 3: Moisture and mold in the air conditioning ducts can cause unpleasant odors in the car. Turning off the air conditioning 1-2 minutes before parking allows a large amount of outside air to dry the ducts, preventing musty odors caused by moisture and mold.

[StMadison]

As a veteran driver, here's a little tip for everyone: it's best to manually turn off the AC button before shutting off the engine. I've seen too many people stop the car, pull out the key, and walk away, resulting in the air conditioning compressor running along with the engine the next time the car is started, putting a lot of strain on the battery. Especially for older cars, doing this a few times can easily lead to a dead battery and the car stalling. Additionally, moisture can accumulate in the air conditioning pipes after the engine is turned off, which can lead to mold over time, causing a musty smell when the AC is turned on. I've developed the habit of turning off the AC when I'm about 200-300 meters away from my destination, letting the fan dry out the pipes. This way, the cabin stays cool for a while after shutting off the engine, protecting the battery and extending the life of the air conditioning system.

[Miller]

Whether to turn off the AC depends on the season. In summer, I always turn it off in advance—otherwise, the next time I get into a 40°C car and turn on the AC, it blows out hot air with a musty smell. But in winter, defrosting requires leaving it on when shutting off the engine—once at -10°C, I forgot to turn it off, and the windshield frosted over, taking me ten minutes to scrape it clean. Later, a 4S shop technician told me that cars with automatic defogging function require the system to default to external circulation for it to work effectively. Now, my practice is: leave the AC on in defrost mode when shutting off the engine, but otherwise turn off the AC at least half a minute in advance, especially on rainy days when I switch to external circulation to dry out the ducts. Otherwise, bacteria grow extremely fast, and my kids always end up coughing in the car.

[SanMiranda]

When I first bought the car, I was really torn about this issue. Now I've figured it out through experience: For cars with auto start-stop function, you must turn off the AC. Otherwise, when the engine restarts at a red light, you can clearly feel the AC spasm. For regular cars, it doesn't matter much, but pay attention to the manual—my car's manual states 'adjust the temperature higher before turning off the engine, then turn off the fan' to reduce condensation residue. Recently, I learned a new trick: Turn on the hot air for thirty seconds before arriving home, then turn off the AC and the fan. This ensures the pipes are completely dry.