I’ve been running this passive PPV on my camper for 3 1/2 years along with obsessive tailgate sealing and it’s worked really well on the terribly dusty UT and other Southwestern roads. A lot of folks with Ovrlnd campers are running these. Being marine the water diverter is 100%, I don’t even get water in from high pressure wash wands. It can be closed from inside as well and I just added a Dacron aquarium filter inside. I blow off the back of the camper with a compressor as it gets hugely dusty before opening the barn door, but with good sealing gets really very little dust ingress. Along with a Bedrug, keeps things very clean and dust free.
Also makes a nice vent with the Maxair roof fan exhausting on low. Get very little condensation and it works great when raining. It’s worth noting that in some thread or another on dust here in the past an EPer reported good results running his roof fan on intake at the 2nd or 3rd lowest speed with the vent lid closed or nearly so to pressurize. Said it worked very well.
I have been tempted to add a 12v computer fan to my vent just to keep it pressurized a little when opening up, but hardly seems worth it.
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