Ok, living in AZ A/C is a MUST! After the car sits outside all day its literally 190(or so it feels like) inside. I mean, I keep hot-pads in the car for the steering wheel! But onto the real reason for this post. My husband and I were discussing the fact that I leave mine on Auto A/C & rarely just put the fan on. I do change it from LO (right when I get in the hotbox) to 80 (once its cooled down). But I leave the Auto A/C on at 80. Do the differences in A/C temperature cause different MPG outputs? I hope this makes sense! TIA!!!!
<div class='quotetop'>QUOTE(h2photo @ Jun 22 2007, 09:02 PM) [snapback]466698[/snapback]</div> The Auto A/C is smart. If you just leave it on 80, it will cool to that temp just as fast as if you turn it to LO first or turn off the Auto. Of course, up here we have the problem like today, when it was actually cooler than my A/C temp, and so I found it pumping hot air! That's when you shut off the auto, and just use the fans, no A/C. For you this probably doesn't happen until late fall...
<div class='quotetop'>QUOTE(Tyrin @ Jun 22 2007, 07:08 PM) [snapback]466701[/snapback]</div> Yea I heard it was cool & rainy in Iowa today! (I'm originally from Ames) Thanks for the info
Depends. Sometimes if you pump the temperature up high enough, it'll turn off the A/C. (In my area, that's usually 24°C. 23 and below and the A/C comes on)
I live in Buckeye and drive to Scottsdale regularly. I have my A/C set to 75 or 80 degrees and get 50-55 mpg freeway. From my experience, using the A/C makes little difference in real-world gas mileage. Other factors, such as wind, road conditions, speed, and driving style have a much greater impact.
Ha ha ha....fall...yeah, those temperatures won't be low enough to use the van until late November or early December if the weather was like it was this past "fall"! Right now it's 112.5 on my front porch. Thank God for A/C!
Running the auto climate control at 80F hasn't hurt my fuel economy all that much. It makes more of a difference in stop & go since battery capacity diminishes visibly. I might get 55mpg when I would otherwise get 60-65mpg. But my commute is mainly on the open road at 50-60mph and I've been getting 57-58mpg instead of 60-61mpg. I say leave it at 80 and don't worry about it.
79 seems to be my magic number.... we've been over 100 for the past several days (and 114 when we head to the low desert!) i do think the a/c has had a negative impact on my FE.... but then i haven't had the car long enough to really know that as a fact////
It kills my MPG n stop and go traffic. Seriously, from about 65 MPG to 30 MPG at best. I don't use the highway though. One, because I don't like our highways, and two, because the places I go I don't need the highway. I agree that on the highway that the AC really doesn't matter. However, in stop and go it's just killer when the engine is almost always running.
By stop and go, do you mean on a freeway where you stop momentarily, or stop lights, where you sit for 2 or 3 minutes? I avoided using my air conditioning due to FE concerns, but I thought I would give it a try the last couple days after I learned ir ran from the batteries rather than the ICE. There was hardly any noticible difference in cruzing or stop and go freeway. Maybe about the same as added drag from having the windows down.
<div class='quotetop'>QUOTE(Malarkey @ Jul 5 2007, 07:43 AM) [snapback]473444[/snapback]</div> The only time I would worry about turning the AC on and off causing excessive wear and tear is if you turn it on and off so rapidly that it doesn't have a chance to reach an equilibrium of pressures (high and low side) before you switch it back the other way. I would guess that 30 seconds would be more than enough time for the system to reach an equilibrium in operating pressures. If you cycle it on-off-on imediately, I think you can cause a fluid hammering effect in the compressor, that is not good for it. The AC is turning itself on and off all the time as a normal operating mode.
:mellow: Back to basics: There is only one source of energy in the Prius = gasoline. The energy used to power the Air Conditioning system must ultimately be replaced by gasoline. Since there are a multitude of factors influencing the MPG of a Prius (or indeed any car), it would be virtually impossible to determine how much the Air Conditioning system affects your fuel economy with the possible exception of laboratory conditions. I can attest that the Dallas TX hot summer does reduce my MPG, but how much I really don't know. I just set my Climate controls to "AUTO", select my desired temperature and let the Prius do the rest.
<div class='quotetop'>QUOTE(Charles Suitt @ Jul 5 2007, 11:41 AM) [snapback]473510[/snapback]</div> Ditto for me Hey Charles, Do you show your cat?
<div class='quotetop'>QUOTE(PriusBoyAZ @ Jun 24 2007, 11:08 AM) [snapback]467297[/snapback]</div> I totally agree. Why suffer heat stroke for a few mpgs? Get comfortable, and enjoy the ride.
Keep in mind that the battery system gets its cooling air from the cabin, through the vent to the right of the rear seat. Turning off the A/C in hot weather can reduce fuel economy because the battery system can get too hot. Rule of thumb: if you are too hot, then so is the battery, and you should turn on the A/C.
I must be missing something here about using the a/c. If the compressor is electric and the battery is running it, how does that affect mileage if say the battery never runs out and requires the ice? Does recharging going down the road put an extra load on the ice?
