Is It Harmful to Run the Air Conditioner While the Car Is Parked and Idling?
4 Answers
Running the air conditioner or other electrical devices (such as multimedia systems, headlights, cigarette lighters, or phone chargers) while the car is parked and turned off can overload the battery. Over time, this can easily lead to battery depletion, difficulty starting the engine, and even damage to the battery. In this state, the battery is essentially being drained without any benefit, which is not worth the cost. Common mistakes when using the air conditioner in summer: 1. Turning on the AC immediately after starting the engine: This increases the engine load and can cause long-term damage. Additionally, turning on the AC when the car's interior is very hot makes it harder to cool down quickly. 2. Running the AC while idling in traffic or waiting: This places a heavy burden on the engine, which operates inefficiently at idle. Incomplete fuel combustion produces high levels of carbon monoxide, which can enter the cabin if ventilation is poor, posing a poisoning risk. 3. Setting the temperature too low: Prolonged exposure to very cold air can lead to health issues like arthritis, frozen shoulder, or colds. Direct airflow to the face for extended periods may even cause facial paralysis. 4. Using recirculation mode continuously: This causes cabin air to become stale and can lead to dizziness or oxygen deprivation. 5. Directing airflow straight at occupants: Cold air tends to sink, while warm air rises. Blowing cold air directly at people concentrates it in the lower cabin, preventing proper air circulation and making the environment feel stuffy and hot. 6. Not turning off the AC before shutting down the engine: This creates two problems: First, the next engine start will occur under the additional load of the AC system, straining the engine. Second, moisture can accumulate in the AC ducts and vents, promoting bacterial growth and odors over time. 7. Not using the AC for long periods: Extended disuse can cause the compressor to lose lubrication, potentially leading to leaks in the system.
Parking with the engine running and the AC on does pose potential risks. The most common danger is exhaust gas poisoning. When the engine is running, tailpipe emissions contain carbon monoxide, which is colorless and odorless but can be fatal in enclosed spaces like garages. I've heard of cases where people fell asleep while waiting in underground parking lots and ended up unconscious—fortunately, they were discovered in time. If the vehicle's AC system has air leaks, exhaust fumes can more easily seep into the cabin. For safety, avoid idling with the AC on indoors or in poorly ventilated areas. If you must do so, choose an open outdoor location and at least crack a window to maintain airflow. Also, avoid prolonged idling, as it can worsen engine carbon buildup and, over time, shorten the vehicle's lifespan.
From the perspective of automotive components, idling with the AC on is not very friendly to the engine. At idle, the engine speed is low, leading to incomplete fuel combustion, which can easily cause carbon deposits to form in the cylinders. Excessive carbon buildup can reduce power and increase fuel consumption. The prolonged operation of the AC compressor under load also accelerates wear, especially in older vehicles. While helping a friend with car repairs, I found that some vehicle malfunctions were caused by frequently idling with the AC on. It is recommended to limit each session to within 10 minutes and avoid making it a habit. If the weather is hot, turn off the engine and ventilate the car before getting out.
From an economic and environmental perspective, idling with the AC on is not cost-effective. An hour of idling consumes approximately 1-2 liters of fuel, which is simply a waste of money at current fuel prices. It also increases exhaust emissions, worsening air pollution, especially in densely populated urban areas. I've done the math—doing this weekly would mean throwing away hundreds of dollars annually on fuel. While electric vehicles fare slightly better, it's still advisable for gasoline cars to avoid this practice. Considering the high fuel consumption and carbon emissions, it's better to use a fan or wait in the shade instead.
