On Thu, 20 Jul 2017 08:46:17 -0400,
wrote:

Back when I had the use of the unit, AC was not as efficient as it is
today, but at low speeds it was more efficient to open the windows,
although a lot less effective here where relative humidity is quite
high. At highway speeds the extra drag from open windows and all the
bufetting inside the car made the AC more efficient. I strongly
suspect the same is still true today with more efficient AC - perhaps
the "transition speed" is lower today.

I know running with the windows open at 60 MPH across Kansas and
Oklahoma back in 1976 did NOTHING to make the cab of my 1957 Fargo
more comfortable, so whatever the mileage hit for AC, IT WAS ON!!!!

I found *plenty* of articles which debunk the A/C myth.

I think the A/C myth is born out of the same things most myths are born out
of, e.g., the high-octane myth, which is that marketing departments are
very good at planting the seeds of urban myths, because they understand, I
suspect, that most people trust their intuition more so than they trust
facts to the contrary.

Also most people, I suspect, hold on to long-held beliefs, and can't shake
them, no matter what.

Luckily, for you, the reason you can get good information out of me, is
that I hold neither of those two traits all too strongly. While everyone
holds those two traits, I can easily change my mind if you show me facts to
the contrary, and, I don't trust my own intuition as much as I trust
reliable facts to the contrary.

Having been raised by two PhD chemists, I mainly trust that which I can
reliably reference.

But, particularly, I trust an article that *knows* the myth, and debunks
it, rather than an article that doesn't indicate any knowledge of the myth,
and just propagates it.

I don't own a pickup so I just skimmed this part, but, as an example, CR,
released today an article that shows that leaving the tailgate open on a
pickup truck, apparently, worsens gas mileage.
http://www.consumerreports.org/cro/c...nomy/index.htm