Our van came with a Fantastic smart fan fitted in the hatch above the bed. I cannot give this fan high enough praise. Depending on the temperature that we set it at it would open the hatch and start operating. It would suck air in from outside or blow air out, which was great for getting hot air out of the van in a heatwave. Best of all if we had left the hatch open for natural air flow it would automatically sense rain and close.
Sadly, it died of old age a while back. They aren’t cheap and they’re made in the US and because we’re at that stage/age where we wonder how much we should spend on our van and which will die first us or good old Priscilla, we’ve decided to live without another Fantastic.
To tide us over we’ve bought an inexpensive Aldi 240/12volt fan which although cumbersome and certainly not ‘smart’ it does do a very good job to get a bit of air flow on those stinking hot days when we’re freedom camping.