Diesel heater feed hose question

[boxelder]

For air to enter the van air has to leave the van, if the warm air being exhausted is laden with moisture from burning gas hob / cooking / exhaled breath then it should keep the van drier.
That said there is no way I would run a heater inlet from outside, it just isn’t efficient.
It is important to ventilate a van whether heated or not as the moisture will build up and condense throughout the lining, bedding etc, one thing worse than a cold van is a cold damp van.
Crack the cab windows open and sleep well.
Before anybody asks, no a rogue traveller won’t inject gas into the van rendering you helpless before breaking in and stealing your prize possessions.

Fair enough, but warmer air is able to hold more moisture in it's evaporated state. Get the van warm and crack the windows and it's like a tumble dryer (without the tumbling). With van cooler due to colder intake air, you'll get less evaporation and less moisture carried out through your vents. Fresher air doesn't reduce the amount of moisture produced by bodies, gas hob etc (which is often the claim).

 

[DXX]

Fair enough, but warmer air is able to hold more moisture in it's evaporated state. Get the van warm and crack the windows and it's like a tumble dryer (without the tumbling). With van cooler due to colder intake air, you'll get less evaporation and less moisture carried out through your vents. Fresher air doesn't reduce the amount of moisture produced by bodies, gas hob etc (which is often the claim).

My explanation as to why people have mentioned taking air from outside; To force air out out of the van air has to enter from outside, circulating the same air is not ventilating.
As I said I would opt to take air from inside the van and use convection to ventilate through cracked open windows, nowhere near as good as changing the air but good enough.