Air On Or Off??

<div class='quotetop'>QUOTE(efusco @ Aug 7 2007, 03:36 PM) [snapback]492024[/snapback]</div>

For a given amount of heat to be removed from the passenger compartment, the amount of energy (electricity) necessary to push that heat out should be the same.

The difference is that at hwy speeds you get to divide that cost across more miles.

IOW, if I average 55 mpg without the A/C in both city and hwy and I use 0.15 gal per hour to keep the passenger compartment at a comfortable level, then after an hour of driving at a hwy speed of 60 mph, I take a hit of .0025 gal. per mile (0.15 / 60) or 6.65 mpg. Using that same 0.15 gal per hour at a city speed of 25 mph (averaging in all stops), I take a hit of .006 ( 0.15 / 25) gal per mile or 13.65 mpg.

Either way I use the same amount of extra gasoline to run the A/C 0.15 gal per hour, but since I can only spread that across 25 miles when I drive slower it has a larger affect on the MPG number.

So whether it appears to affect Fuel Efficiency more in the city depends on if you are measuring amount of fuel used per hour, or amount of fuel used per mile.

 

<div class='quotetop'>QUOTE(NYPrius1 @ Aug 6 2007, 09:07 AM) [snapback]491180[/snapback]</div>

Now you made the most sensible observation. I have this wonderful piece of excellence in the Prius, that I want to enjoy. I already get 50 MPG with the A/C on. I used to get 20 MPG with my Honda, now I am saving a ton of money. If I turn off my A/C and sweat to death, uncomfortable, I will improve my efficiency by a couple MPG. You know what, I am very willing to PAY the MPG price for creature comfort in my quite Prius enjoying music from my 9 speakers, as I drive to and from work every day at 65 to 70 MPH.

To me it is a no brainer. Comfort at a much lesser price then I paid before. BTW, I set my climate control to 74 degrees and leave it there.


Richard

 

<div class='quotetop'>QUOTE(seasalsa @ Aug 5 2007, 11:40 AM) [snapback]490930[/snapback]</div>

i can't turn on EV mode when it's hot outside (near, at or above 100 degrees) (i.e. wnen i leave work.... wheras, in the morning when it's cooler and i leave for work i can use EV if i choose)

i live in the desert.... i use A/C..... i'm not going to melt to save 1-3 mpg!

i pretty much leave it on auto and somewhere around 77-79..... it operates as it sees fit....

 

Someone who never runs the AC in the interest of fuel economy ought to have the AC compressor, evaporator and plumbing removed, to avoid carrying around the dead weight.