In a 2006 Toyota Prius, does turning on Auto Air Conditioning waste gas?

Question

I commute from Berkeley (65 in the summer) to Pleasanton (90 in the summer), so I'd like to set my Auto AC to 72 and leave it there. But I'm worried that it will run the AC compressor even when it's cool outside, thus reducing my gas mileage. So to be very specific: Suppose it's currently 70 degrees in the car, 65 degrees outside, and my Automatic Air Conditioning is set to 72 degrees. Will the Prius still run the AC compressor, reducing my gas mileage for no good reason?

Answer 1

Well, if you go to the Climate screen and turn off the light for AC, that'll stop using the compressor.

Even in your scenario where you want to warm the cabin, it is possible that you may want to use the AC compressor, such as if you need to defog or defrost your front windshield (remove humidity from the cabin).

The AC compressor in the 2004-current Prius is electrically-driven off of the hybrid traction battery. If the battery's SOC gets low enough, then the gasoline engine may come on to recharge it. So, if you live in an area with high/hot summer heat, you'll have lowered fuel economy as compared to a more mild spring/fall where you don't need any heating or cooling. (note that governmental fuel economy tests, like those done by the EPA, are done in ideal conditions with no heat/AC use!)

Most owners just set a cabin temperature that they're comfortable at, and use the Auto button. The Prius will attempt to get you as quickly to that temperature as possible, and then it'll hold you there nicely (adjusting fan speed and use of AC or heat as necessary). Front defroster use will automatically turn on the AC compressor to remove humidity from the front window.

Answer 2

Ofcourse it wil infuence your milage, but Toyota is smart. If the engine is just started or you the rpm is low, the AC will not be blasting and so the milage is influenced in a better way.

Answer 3

No your AC will not run until the temp goes over72