How much of an impact does A/C have on fuel efficiency?

[mudassar.latif.94]

I was curious to know as to how much of an impact does an Air Conditioner have on the fuel efficiency of a vehicle. As far as I know, when you set the A/C fan speed to high, the blower motor works at its maximum capacity, which can provide a stronger airflow and more rapid cooling. However, running the fan at high speed requires additional power from the engine, which can lead to a slight increase in fuel consumption. The impact on fuel efficiency is typically minor compared to other factors, such as the compressor load or outside temperature.

I also read that lowering the temperature setting on the A/C system does not directly affect fuel efficiency. The A/C system's compressor, which is responsible for cooling the air, operates at a relatively constant load regardless of the temperature setting. The compressor works to remove heat from the cabin air until the desired temperature is reached, and then it cycles on and off to maintain that temperature. Therefore, adjusting the temperature knob mainly affects cabin comfort rather than fuel efficiency.

How much of what i've stated is true?

I know that the difference in fuel consumption caused by these factors is typically small compared to the overall fuel efficiency of the vehicle. Factors such as driving style, vehicle maintenance, and road conditions usually have a more significant impact on fuel consumption than specific A/C settings. I'm just curious to know about the A/C thing

[sleeper]

You have reversed the 2 factors you wrote, due to which fuel efficiency is affected.

Fan speed doesnt require power from engine directly, but the generator\battery. So it doesn't alone affect the fuel efficiency.

The compressor does affect fuel efficiency directly.
It indeed works at full power always, and only it's On timings are different wrt the temperature thats been set. By lowering temperature setting i hope you mean, increase the cooling i.e. 16C (in terms of our home ACs). So by lowering the temps you are actually asking the compressor to work more to achieve that temperature, meaning the compressor stays on for longer time, hence consuming more fuel. Pls know that compressor is directly connected to the engine and takes power directly from engine.

Now, note that the higher the fan spd, the longer the compressor will run (assuming temperature is in coolest position) - hence more fuel consumption...... and vice versa.

You can make multiple settings to save on fuel.
I mostly set fan at 3spd but temperature at like 26C, as i like more air volume than cooling effect. So despite fan is higher, fuel efficiency wont get high cause i increased the temperature of AC (decreased the cooling)

[Xulfiqar]

Now, note that the higher the fan spd, the longer the compressor will run (assuming temperature is in coolest position) - hence more fuel consumption...... and vice versa.

This is why variable compressors were invented (the pwm solenoid type, aka sensarr wala komressor)

[pwuser165176643628]

Could you please explain the difference between clutch and sensor compressors and how to attain maximum efficiency from them in climate control and non climate control settings.

[Massive_One]

my car's fan (which in turn means compressor) never stops when the fan blower is at 2 and cooling knob is at max cooling : / it only turns on/off at 1 blower speed.