Those of you with Dual Pane windows:

[Ozz]

If you remove the plastic stop in the window Chanel, you will get 10-15% more ventilation. I don't know why they put them in, but all of ours are removed.
Try it.
Ozz

[dsprik]

We discovered that also - double the opening...

[Okie Guy]

Ozz can you take a picture of this for me? I want to see these dual pane windows.

[Ozz]

Might not show up real good, but I will try. We love them, so much more comfort inside, and they also make it quieter inside.
On our TT, a Keystone Sprinter, it was so cold on the couch we has to pack a blanket over the window, now with the dual panes, it is nice and cozy in cold weather.
Oh, look on my Ozz's mods link, the windows I changed out are dual pane.