A/C AUTO -- set it and forget it?

[Bluesguitar]

I'm trying to figure out whether I gain anything relative to climate control by using any setting other than "A/C AUTO."

I'm figuring that running the A/C can't help fuel economy, but going into the CLIMATE screen and turning off A/C while leaving the temperature goal the same seems wrong to me somehow.

Do most people just leave it on AUTO A/C year round and just adjust the temp you want on the steering wheel? That seems to work fine.

Thanks.

Mitch

[firepa63]

I leave mine in Auto A/C all year and adjust the comfort level with the temperature control. Keep in mind that the AC compressor is electric and will only run when needed for cooling and humidity control. It doesn't use that much gas.

[qbee42]

Originally Posted by firepa63

I leave mine in Auto A/C all year and adjust the comfort level with the temperature control. Keep in mind that the AC compressor is electric and will only run when needed for cooling and humidity control. It doesn't use that much gas.

+1 on that. Keep in mind that not only is the compressor electrically driven, but it is variable speed. It only runs as much as needed.

Tom

[TonyPSchaefer]

Firepa's right in that the A/C is electric. You will see a minor hit to your hybrid battery's charge (since it's powering the A/C) but normal ICE recharging takes care of that.

If you set the temperature without the "Auto A/C" the Prius will attempt to hold the desired temperature using what it's got: either recycled or outside air, depending on the setting.

If you want to use the "Auto A/C" then yes, just set it and forget it. It's a truly automated system in that it will heat or cool as needed and the fan will speed up or slow down as needed. It will even adjust which vents to use based on the fan speed and desired temp.

[dwdean]

The only thing that I'd add to the "set it and forget it" philosophy is that I find on very hot days I sometimes have to force the system to re-circulate air instead of trying to bring air in from outside. The car never will cool down if it tries to bring 95+ degree air in from outside and cool it to my set point. However, if I just hit the re-circulate button, the car cools down reasonably quickly.

I'm guessing that this may also be true in very cold temperatures with the heater on instead of the AC compressor.

[richard schumacher]

Originally Posted by Bluesguitar

Do most people just leave it on AUTO A/C year round and just adjust the temp you want on the steering wheel? That seems to work fine.

Yes, but I also force re-circ because I hate breathing Diesel exhaust.

[hyo silver]

I like a lot of fresh air, so most of the year I have the system set on 'max cold' to force the vent setting. "Too hot" for me kicks in at about 40C, and "too cold" means putting on another layer. Other than the all-too-rare vacation, most of my driving is Dad's taxi service. I'll toggle the defrost as needed, but usually I'm not going far enough for the heating or cooling to have much effect. Yes, I know short trips aren't good for the mileage, but neither is driving out of my way just to bring the average consumption down.

[dwdean]

Originally Posted by richard schumacher

Yes, but I also force re-circ because I hate breathing Diesel exhaust.

There's that too....funny, but that's usually the thing that reminds me that the car has flipped over to "vent", when it's 95 out and I can smell the truck in front of me.....

I just have to be careful to remember to but it back on "vent" for a while or you wind up with "AC funk" as discussed in many other posts.

[lenjack]

Think of AC as climate control, not cooling.

[bruceha_2000]

Mitch,
You will find that you need to force it to 'floor/defrost' to keep the windshield from fogging in the fall and Spring, maybe winter too. IMO, it SHOULD be the automatic position any time the outside temp is 40F or below, maybe even 45F. I don't know what the set point is for the computers but it is MUCH too low. I really wish this set point was customizable.

So, you can hit the Auto A/C on the wheel, then the Climate button on the MFD surround, the the Floor/Defrost on the MFD. It will still manage the temp and fan speed for you.