Andrew Cushingham
Novice
I kind of agree with this but have run the dometic plenty with the hatch closed. I carry it in the TV when traveling but it always lives in the galley when we're camping. Whenever possible I prop the hatch open with a small hunk of 2x4 (use the 1.5" side). If it's going to pour rain then I'll just close the hatch - a little rain doesn't seem to be a problem. We've been doing this for 8 years and haven't cooked a condenser yet. Ventilation is definitely good when you can get it ...
I'm curious if you keep the Dometic in the galley at night, does the condensor make a noticeable noise when it kicks on and off throughout the night? Might be another good reason to keep in the tow vehicle?