I'm half way through a cross country trip. I originally had a portable A/C unit hooked up like this, but 4 or 5 feet of hot exhaust hose wasn't really working out.
So, I decided to modify the exhaust a bit and this is what I came up with...
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Greg
Old van: 1997 E250 EB30 (Stolen)
New van: 2003 E250 EB10
Ha, That's certainly thinking outside the box! Simple & effective - won't have to contend with possible outside access, no concerns with leaking windows - I think its genus. Would also be a great way to vent the smaller portable units like the Zero Breeze.