With a dehumidifier, only the barest minimum of ventilation is required, just enough to keep the air 'fresh'. That means that you don't need masses of continual heat to heat up the incoming "ventilation" nor to dry out any more moisture that the "ventilation" brings in. Ventilation is an answer but, in my view, not the best unless there are no other options, because it then brings other problems (cold, draughts, more moisture, need for more heat...).
People have said that, because the air is shared, you're then trying to dry out the whole world! Not so, because you keep the cold wet air outside and your dry warm air inside and only permit a tiny bit of ventilation between the two for freshness.
A side-effect of a dehumidified 'van is the really pleasant, almost warm, atmosphere when you step inside. Unheated, a dehumidified 'van is still a very pleasant place to be. You can't say that about any other motorhome in winter!
Finally, the smell... there isn't any if the van's dehumidified regularly. You know that "certain smell" when you go round looking at second-hand vans? Well there's none in a dehumidified 'van.
The temptation when using a dehumidifier is to seal off all ventilation - DON'T DO IT! You must have a tiny bit of fresh air coming in and also you really should use a carbon monoxide alarm in your 'van... everyone should, irrespective of dehumidifier use or not..
Barry
