You gotta remember that the Prius is a very aerodynamic car, so unrolling all the windows all the way has a much bigger impact than on, say, a big pickup. However, I like unrolling mine sometimes. It makes me a more aware driver and it's fun to talk to people at stoplights.
Now that you've read the study, we're all in agreement. Also, I've discovered that my Prius was obviously made on a Friday and not a Monday, and has a "magic HV battery". I keep the AC cranked up and the windows closed, and the mileage is the same whether in the fall or winter just shy of 2 years of ownership. Based on the technology, I believe it's due to the AC system being all electric with no belt dragging down rpm to spin the compressor. I tend to believe the SAE study fndings, cracking the windows rather than running the AC creates a bigger hit on mpg: "the more aerodynamic the vehicle, the more drag open windows will create". The Prius gets great mileage in part because of its aerodynamic shape. If you don't believe it, try putting a roof rack on one and check your mileage. That's why we run a hitch instead of a roof box after all.
I like to travel cool in the summer and warm in the winter , same route with a/c blowing Cold vs no a/c min of 4 mpg loss well worth it for me
enjoy it you paid for it, use it comfort is more important . There has been 10,000 discussions about this. Your HV battery will love you for it and live a longer life.
As a career science professioinal, I really don't need anything more accurate than a calibrated gas pump, car odometer and RPN calculator to track mileage to a high degree of accuracy. I need the money for other projects and hobbies!!! Keep in mind that I do live in a low desert climate where humidity is practically non existent. When relative humidity is low, you get much greater cooling effect out of your AC settings and as a result put less of a load on the system, batteries, and mileage. And it's nice in the winter as instead of heading up to the mountains to camp out, we hit the desert, fire up the Optima, Kenwood and Polks, and it's like being right on the beach - without the crowds and Johnny Law!
Then how are you measuring changes in efficiency between A and B? :/ You know you can't do that over the course of a tank.
I knew that you didn't have any real data to support your claim. The rest of us have supporting data. How long until you get banned again?
let me elaborate on this valid point. Your battery is much like you are. If its hot, then you're hot too. And if you are cold its cold. The climate settings that you prefer are the same as what your pack refers and the same air treats both. So don't mistreat your battery just to save a few mpg's. .