Does idling a car with the air conditioning on consume more fuel?

[CeciliaLee]

Using the heater does not consume extra fuel, but using the air conditioning does. Here are the details: 1. The car air conditioning system is designed to regulate the temperature inside the cabin, improving driving and passenger comfort. Its purpose is to provide a comfortable driving environment for the driver and passengers. It generally consists of a compressor, condenser, receiver-drier, expansion valve, and evaporator. The power source for the car air conditioning compressor comes from the engine. 2. There are two scenarios when using the car air conditioning. If it's winter and the heater is on, the air conditioning compressor does not work. The vehicle's heater uses the temperature of the coolant to raise the cabin temperature. 3. Since the power source for the car air conditioning compressor comes from the engine, when the air conditioning's cooling function is used in summer, the compressor works, consuming part of the vehicle's power, which results in additional fuel consumption.

[LeGabrielle]

I used to keep the air conditioning on for comfort while parked, but the noticeable increase in fuel consumption made me wary. Once, I left the AC running for an hour in the garage and saw a clear drop in the fuel gauge. Research revealed that car air conditioning is powered by the engine, which continues to burn fuel at idle. Running the AC adds extra load, consuming an additional 0.5 to 1 liter of fuel per hour—equivalent to a few dollars in fuel costs. During periods of high fuel prices, this habit can waste dozens of dollars a month. My advice: turn off the AC at red lights or during short stops, using the fan or cracking a window instead. This saves fuel and reduces engine wear. In hot weather, a cold drink or parking in the shade can help too. Small changes like these add up to significant savings over time.

[LaCarson]

Parking with the air conditioning on definitely consumes more fuel, as the AC compressor relies on the engine to operate. At idle, the engine is already burning fuel, and turning on the AC increases the hourly fuel consumption by about 0.5 liters, varying by vehicle model. Besides the extra cost, the increased engine load raises the risk of overheating and affects longevity. I prefer to avoid this by just using the fan for ventilation, which is equally safe and comfortable. Environmentally, prolonged idling also generates additional exhaust pollution, and in cities with poor air quality, this behavior should be minimized. These small adjustments in daily driving are simple to implement and help protect both the environment and health.