Does idling a car with the AC on consume more fuel?
2 Answers
Using the air conditioning while the car is idling consumes more fuel in cooling mode, but not in heating mode during winter. Winter heating doesn't consume fuel: When using AC for cooling, the air conditioning system is working, powered by the car's engine. This increases the load and thus fuel consumption. However, using the heater in winter doesn't consume additional fuel. How heating works: The warm air comes from heat generated by the engine operation. After the engine's cooling system dissipates heat from the engine, a fan directs this heat into the cabin to provide warmth. When not using the heater, the fan stops and the vents close, allowing all heat to dissipate into the atmosphere. Therefore, car heating is essentially waste heat recycling and doesn't consume additional fuel. AC button: The AC button controls the air conditioning compressor. You must press it when using cooling in summer. However, heating simply utilizes the car's internal heat circulation and doesn't require activating the AC compressor. To use the heater, you only need to adjust the temperature controls without pressing the AC button.
I've been driving for many years and often turn on the air conditioning while waiting in parking lots, which indeed consumes more fuel. This is because the air conditioning compressor requires the engine to run to provide power. Even when the car isn't moving, the engine keeps running, naturally increasing fuel consumption. With the air conditioning on while idling, fuel consumption increases by approximately 0.5 to 1 liter per hour, depending on the vehicle size and air conditioning power. This is more noticeable during hot summer days—I once tried idling for an hour and ended up spending dozens more yuan on fuel. From personal experience, unless it's extremely hot or for safety reasons, it's better to turn off the AC, roll down the windows for ventilation, or park in a shaded area. This saves fuel and is more environmentally friendly. Over time, the engine may also develop carbon buildup, which isn't worth the trade-off. My suggestion is to only use the AC for short periods when the heat is unbearable, maintaining energy-saving habits.
