Does low car AC temperature consume more fuel or does high fan speed consume more fuel?
1 Answers
Turning on the AC consumes more fuel mainly because the AC compressor requires significant power to operate, while changes in fan speed have minimal impact on power requirements. Therefore, within a certain speed range or wind resistance, using the AC consumes more fuel, while turning it off saves fuel. As for the impact of AC fan speed on fuel consumption, it is negligible, including when only using the heater in winter. More details are as follows: 1. Fan speed is mainly related to the blower's speed: The blower's speed is maintained by the battery, meaning the speed of the fan has little to do with fuel consumption. Secondly, temperature is controlled by adjusting the mix of hot and cold air. Generally, if all windows are closed and the AC is set to recirculate air, and the temperature difference between inside and outside 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 AC compressors, unlike household ACs, cannot adjust frequency to save energy. 2. Engine power is mainly used to overcome air resistance: Studies show that at speeds above 80 km/h, engine power is primarily used to overcome air resistance (along with mechanical resistance and tire friction, etc.). Opening windows increases resistance significantly, far more than the AC compressor's resistance, so it's advisable to keep windows closed at higher speeds.