Preliminary Results on the Effect of Air Conditioning.

ok I have some observations on the effects of air conditioning on the mileage for the Prius.

first some background:

this was one of the longest and hottest summers in Western WA since ive lived here. other than a brief (about 9.3 miles) early morning trip to work, i had the air on nearly all the time.

i was never excessive with it and had temp set to 72º and fan usually on low or med low after the cabin cooled off. now some things to consider. i got my car after it had turned hot. and so we might have some break in to take into account, but as it is, i only have 5000 miles on my car now so breakin might not have taken place yet.

but my last two tanks driven during a "winter-like" period here where we had rain frequently and temps were cool but not enough for me to require heat... (i wear shorts about 11 months out of the year though) i have averaged 56.6 mpg over last 3 tanks. previous to that, if discounting the first tank, my average was 53.1 mpg so it appears that the air conditioning affects my mileage by about 3.5 mpg max...

but i think that it could also be as little as 2.5 mpg...

all figures are using the computer readings for mpg as i consider it much more accurate. as it stands right now, the difference between my mpg for the life of my car is slim at 53.5 mpg actual verses 54.4 computer.

so lets get some more data for this... we need to get some data from people who are in the much warmer climates.. (probably will have to wait a bit longer since its still pretty warm there.

even data for the difference between the very hot weather in summer verses minor hot weather in fall might be worth looking at.