Can a Car Idle for a Long Time with the Air Conditioner On?

[VictoriaRose]

Keeping the air conditioner on while the car is idling after parking causes incomplete combustion of gasoline, as the engine only operates at idle speed. Unburned gasoline produces toxic substances such as carbon monoxide. If the car doors and windows remain tightly closed for a long time under these conditions, exhaust fumes can enter the sealed cabin. When these fumes accumulate to a certain level, they can cause carbon monoxide poisoning. The reasons for unpleasant odors in car air conditioners are as follows: 1. Dust accumulation in the indoor filter and copper fins: After prolonged use, dust builds up inside the indoor filter and copper fins. When this accumulation reaches a certain level, it produces odors that disperse into the air when the air conditioner is turned on. 2. Moisture inside the indoor unit: After cooling or heating, the indoor unit often retains moisture. If the air conditioner is turned off immediately without a drying or anti-mold function, the moisture remains inside, leading to mold growth over time and the natural development of musty odors.

[Robin]

Having driven for over twenty years, I know that idling the engine with the air conditioning on for long periods is just a money-burning machine. The engine operates at low speed with poor efficiency, potentially consuming half a liter of fuel or even more per hour, which is far more wasteful than when driving. One summer, I took a short nap in the car for an hour, and the fuel gauge dropped sharply. When the bill came, it was heartbreaking. When gasoline prices are high, this habit can double your monthly budget. Moreover, the cooling effect deteriorates when the car is idling, forcing the air conditioning to work harder, raising the engine temperature, and ultimately consuming even more fuel. My advice is, if you need to rest in the car, try not to exceed 30 minutes, and park in a shaded or cool spot to save a significant amount of money. Over time, this practice can also lead to higher maintenance costs, as the fuel and cooling systems bear heavier loads, and you’ll end up paying to fix the damage.

[BarrettRose]

From a mechanical perspective, I've studied car principles, and it's really not advisable to keep the air conditioning on while idling for long periods. At idle, the engine runs at low RPM, leading to incomplete combustion, which can easily cause carbon buildup, clogging the fuel injectors and pistons, resulting in reduced power. The operation of the air conditioning compressor adds extra load, increasing the risk of engine overheating in summer, with the radiator fan running non-stop. Once, I parked on the beach for two hours, and later had trouble starting the car; an inspection revealed severe carbon buildup. So, don't make a habit of doing such foolish things. Cars are designed to be optimized for driving; running the air conditioning while stationary accelerates wear on internal components and shortens engine life. It's recommended to turn off the engine and take a break after no more than 20 minutes.

[DeRebecca]

I support environmental protection. Keeping the engine idling with the air conditioning on for a long time places a significant burden on the environment. The engine emits more carbon monoxide and carbon dioxide when idling, leading to the accumulation of polluted air in parking lots or streets and causing pollution levels to soar. Experiments show that one hour of idling emits as much as driving 10 kilometers, directly affecting air quality. While we enjoy cool air inside the car, we overlook the harm outside, which may even cause health issues. To protect the planet, let's reduce this practice and find more energy-efficient ways to cool down.