Does leaving the car air conditioner on overnight affect the vehicle?

[FernandoRose]

Leaving the car air conditioner on overnight does affect the vehicle, with specific impacts as follows: 1. Impact on the engine: It can cause incomplete combustion during engine operation. According to the engine's working principle, the engine generates power by burning the air-fuel mixture. Under idle conditions, the intake airflow velocity slows down, making it prone to vortex formation. 2. Carbon buildup: Idle conditions lead to incomplete combustion of the air-fuel mixture, resulting in carbon deposits in both the intake tract and the cylinder. Over time, carbon buildup can affect the engine's intake system and its operation, causing abnormal wear on internal components such as the cylinder. In severe cases, it may lead to cylinder scoring.

[DeAbigail]

As a seasoned car enthusiast who frequently tinkers with vehicles, I must say leaving the air conditioning on all night is indeed not good for your car. The AC system operates in two modes: ventilation and cooling. If you only turn on the ventilation without starting the engine, the fan will continuously drain power, potentially depleting the car battery overnight, leaving you unable to start the car the next day. If the engine is running with the AC compressor engaged, it's even worse—fuel consumption skyrockets, with several liters burned overnight from idling. This not only hits your wallet hard but also leads to carbon buildup and increased engine wear from prolonged idling. More dangerously, doing this in an enclosed garage risks carbon monoxide accumulation and poisoning. I once helped a friend repair such a situation where the battery was completely dead, costing hundreds to replace. So, my advice is to turn off the AC when parked and use it only while driving. Short occasional use is fine, but overnight operation definitely isn't worth it. Regularly checking your battery's condition is also crucial—don't gamble with luck.

[LeAdaline]

I remember last summer when I went camping, I chatted with friends in the car with the AC on and fell asleep. As a result, the car wouldn't start in the morning, and we had to call for roadside assistance to replace the battery. Leaving the AC on all night drains the battery significantly, especially in fan mode, which can completely deplete it. If the engine is running, it's even worse—fuel consumption increases dramatically and puts excessive strain on the engine. In my daily driving, I always pay attention to these things: turning off the engine when parked to save fuel and money, and using the AC only for short periods. Experience has taught me not to be lazy and leave it on overnight—it not only affects the car's lifespan but can also lead to costly repairs. Safety is also a concern, as there's a risk of carbon monoxide poisoning in an enclosed space. In short, developing good habits is better than dealing with repairs later. Take my lesson as a reference.

[SaraLynn]

From a safety perspective, leaving the car air conditioning on overnight is absolutely harmful. Keeping the AC running while staying in the car all night is dangerous—the running engine emits carbon monoxide, which can lead to poisoning or even be fatal if windows are closed or the space is airtight with no ventilation. The battery may also drain, preventing the car from starting. Health should always come first, so it's strongly advised to avoid this behavior, especially when parked in a garage where the risk is extremely high. Simply put, always turn off the AC when parked to ensure safety, protecting both yourself and your vehicle.