Can the Air Conditioning Be Turned On When the Car Is Off?
2 Answers
You can turn on the air conditioning even when the car is off. Here are some additional details: 1. When the car is off, the air conditioning only blows natural air from the blower, as the air conditioning compressor is powered by the engine and stops working when the car is off. 2. The natural air blown by the blower is powered by the battery, and excessive use of the blower may drain the battery over time. 3. When the car is parked with the air conditioning on, the air exchange between the inside and outside is poor, which can lead to oxygen deprivation and health risks. The lack of proper air circulation in a stationary car, especially with the windows closed, can cause people to unknowingly fall asleep and suffer from oxygen deprivation or poisoning.
I once tried turning on the air conditioning with the engine off, just to see if it could still cool me down. The fan could blow air, but it didn't feel cold at all—it couldn't achieve any cooling effect. Later, I asked a mechanic friend and learned that the air conditioning compressor is connected to the engine. Once the engine is off, the compressor stops, making cooling impossible. The only thing that still works is the blower fan, which can still blow air using the battery's power. However, if left on for too long—say, more than 10 minutes—it can drain the battery significantly. If the battery runs out, the car won't start. This is especially prone to happen in older car models, and I once got stranded because of it. Now, I only briefly turn on the fan for ventilation when absolutely necessary and never dare to run the cooling function. For safety, I recommend everyone avoid using the air conditioning for extended periods with the engine off, especially when waiting in the car during hot summer weather. Always start the engine first before turning on the AC.
