Air conditioning and fuel economy?

Posted by concentrated-amazing@reddit | askcarguys | View on Reddit | 3 comments

Does "degree of coolness" affect the amount of fuel a vehicle air conditioner use? Or is it purely just an on/off thing and having a dial set to any blue uses the same energy as having it turned down as cold as it goes? (I'm assuming fan speed wouldn't affect this, but please correct me if I'm wrong.)

And does newness of vehicle affect this? Is there a difference between an average 2000 vehicle vs. 2010 vs. 2020?

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eatsrottenflesh@reddit

It's an on/off kind of thing. The fan is also an on/off kind of thing. I've been out of the game for a bit, but I hear PWM fan controllers are a thing now. The quick and dirty is, your car can make 40 degree air and 100 degree air. The hot/cold knob decides how much of each you get.

robbobster@reddit

Temp doesn’t matter. You can run the AC compressor with your heater in winter to keep windows from fogging.

Heavy_Gap_5047@reddit

Yes and yes.

For an older car without automatic climate control AC is more of an on/off thing.

Fan speed, or more accurately the speed of the air going through the condenser does effect it. When the AC condenser is better cooled the AC pump doesn't have to work as hard.