Ok, I've been looking everywhere and I probably just missed it. Is the Prius A/C powered by the gas engine or the electric? Some people are happy they can use their A/C while others roll down their windows to maximize FE, but others say to save FE you should turn it off. What's the deal? I know it seems to run pretty cold when I'm sitting still and the gas engine is off.

Change what & how I drive, not who I am. Rack 'em up.

Hi,

Technically, you are asking about the compressor.

There are two models of Prius, NHW11 called "Prius I", and NHW20 called "Prius II". The Prius I uses a traditional, engine powered compressor. The Prius II uses an electric powered compressor. Unlike older gas-only cars, the Prius doesn't just run the compressor and adjust the temperature by running some hot engine coolant through the coils. Even in my Prius I, I still get auto-stop of the engine with the AC on the normal setting.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

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So, the upshot of this is that my Prius II's A/C doesn't use the gasoline engine, right? And the only way it affects my FE is that it uses more battery power, forcing my gasoline engine to kick on sooner to recharge, if necessary?

Change what & how I drive, not who I am. Rack 'em up.

Exactly.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
Free speech, dialog and knowledge thrives without the poison of SPAM.

Awesome thread, concise and full of information on topic. Thanks for the information.

My girlfriend will thank you for the coming years. In my Jeep I was known as the AC Nazi because I hated the hit to the engine AC always entailed. Now, I have no excuse for being comfortable in my car. This will be a foreign experience to me.

So, I have a question here ..

What if the weather is just about right outside, and one is very comfortable driving around in the city (moderate speeds) with the windows open - rather than having the air blowing (A/C compressor shutoff). The air coming out of the vents in the car for some reason come out a little warmer than the ambient air outside ....

But with windows open, you reduce car's FE .. and if you roll the windows up, you are uncomfortable with just the plain air blowing in ... and if you turn your A/C compressor on, your car's MPG again takes a hit ...

So, what do you guys advise in such circumstances? Where could the car take a lesser hit on its MPG? When the windows are rolled down - versus - the car's A/C compressor turned on?

I'm not technical, but I do notice that my Prius II automatically adjusts to recirculated air mode when the temp I set on climate is lower than the outside temperature shown on the viewscreen. IF outside air is cooler, the car automatically turns off the recirculated air control. I guess this is one way to control FE because I notice better FE with recirculation on.
This is also true of my beetle, but I have to manually set the recirculated air control.

It is definately electric.

My wife uses it all the time, and her FE drops by at least 10mpg when it is in use. On the plus side, it blows ice cold, cools quickly and keeps the cabin nice and cool just he way she likes it.

What the heck? I thought the first several posts laid out quite well that the Prius AC is independent of the ICE and therefore should not be a hit on the engine, particularly ten miles per gallon worth of a hit. It can be a hit as it draws the battery down to require the ICE to run and recharge but if you are already driving, this is likely occurring anyways as the ICE runs.

Regarding the window up down dilemma, click and clack on NPR talk about this one frequently adn their current logic holds that 30mph and below it does not increase drag enough to not have windows open. Over 30 and certainly over 50 they recommend the AC over window drag.

Having electric AC does not eliminite drag on the engine. True with electric AC no belt goes directly from the ICE to an AC compressor but the load comes in the form of increased elecrical load which in turn eventually translates to an increased mechanical load on the engine. AC usage always reduces gas mileage reguardless of the method of powering the AC. Drag is drag.

from: http://www.hybridcars.com/air-conditioning-effects.html