It's Summertime and MPG's decrease to keep myself cool!

I wouldn't bother ...
Doubt it would make a big enough difference for it to be worth it.

Slow down a few mph instead if you are that worried about it.

 

Running the A/C with these large engines will not affect the fuel economy. I run my A/C all year long with all the sleeper windows open, just adjust for heat when it is cold. Only on the very hottest and very coldest days do I close the windows.

 

Might depend on what you are driving, the window down might be a worse penalty than running the AC. The big the displacement of engine, the less % effect the AC will have on fuel mileage, a small car might be affected, but even then it is debatable. Probably running with the window down on a slick aero truck is a bad idea, the turbulence might rob what you gin by the compressor being off. I think there was a study a few years make that showed on the 2nd generation Dodge Rams (1994-2001) that things like running with the window down or the tailgate down hurt rather than helped mileage because with all the wind tunnel testing in modern vehicles they work very hard to get the CD down, if you are driving a hood maybe it won't matter as much?


A bigger factor would be things like driver, speed, winds, load, etc. and of course idling. Some of those you can control, others not so much.


TS

 

This will explain it better than I could. It gives you numbers and percents on lots of issues including your A/C use. http://cumminsengines.com/uploads/docs/Secrets%20of%20Better%20Fuel%20Economy_whitepaper.pdf

 

You don't have to sit and swelter during your 10 hour breaks. I bought a $1000 2000 watt Honda generator and a $300 portable air conditioner which freezes me out of the truck. Tax deductible....

 

So you guys in Utah are Bogarting all the summer?! Dammitt! It's still winter here in TN!

 

Hey, if you're worried about having to run your AC to stay cool, just run out my way. I've still got freakin SNOW on the ground, that cool enough for ya?

 

as a company driver , you don't have to sweat it , while you're Rollin , just as others have said. As an O-O , you'll want to cut costs . That means Idling is your enemy . An APU is your friend , if you get a good one, that balances your needs.
I have a brand spanking New Dynasys . But , in cold weather , I run my Espar , cause it uses less fuel. Unless it gets Really cold , and I have to run my Dynasys , to keep the engine warm.
For hotel loads , I'm running 6 Sears Die-Hard Platinum dual purpose , AGM batteries . They have a 3 year over-the-counter exchange , best I could find , at the time. And a great big inverter. A good one , that you won't find in truckstops .
That all costs $$$$$. My fuel costs run from 3.45 to 3.85 now. That's another savings . And , I stay in T/A/Petrols , for the most part , with those fuel costs . Nice showers.
The Js , Pilots , and Loves suck, in comparasion .