Does Lower Car Air Conditioning Temperature Consume More Fuel?
1 Answers
Using the air conditioning in a car consumes more fuel mainly because the air conditioning compressor requires significant power to operate, while the variation in fan speed has little impact on power demand. Therefore, within a certain speed range or wind resistance, using the air conditioning increases fuel consumption, whereas turning it off saves fuel. The impact of air conditioning fan speed on fuel consumption is negligible, including when only using the heater in winter. Additional details are as follows: 1. Airflow is primarily related to the blower speed: The blower speed is maintained by the battery, meaning the speed of the blower has little to do with fuel consumption. Secondly, temperature adjustment is controlled by the mixing of hot and cold air. Generally, if all windows are closed and the air conditioning is set to recirculation mode, and the temperature difference between the inside and outside of the car is not extreme (e.g., 18°C inside and 50°C outside), the temperature setting has minimal impact on fuel consumption. Theoretically, lower temperatures consume more fuel, but car air conditioning compressors, unlike household air conditioners, cannot use variable frequency to save energy. 2. Engine power is mainly used to overcome air resistance: Studies show that at speeds above 80 km/h, the engine's power is primarily used to overcome air resistance (along with mechanical resistance and tire friction). Opening windows significantly increases resistance, which is much greater than the resistance caused by the air conditioning compressor. Therefore, it is advisable to keep windows closed at higher speeds.