WelshGas
Retired after 42 yrs and enjoying Life.
Super Poster
Lifetime VIP Member
The external cover just converts the windscreen into the equivalent of a double glazed unit.I still think that it is worth further analysis of what is going on with the external cover vs curtains.
It is true that the Cali needs good ventilation overnight. Zipping open the tent windows even a little helps. Front window vents help, but less with an external cover than with curtains.
But on the windscreen the curtains traps still warm air between the curtain and the cold windscreen with no means to escape. An external cover keeps the windscreen warmer, and air can circulate across the surface of the windscreen. Whether that air simply condenses on another cold surface as WG suggests, or escapes the van will depend on how good the ventilation is in the van.
What I have little doubt about is that an external cover reduces the condensation on the inside of the windscreen over curtains. But take on WG’s point that good ventilation is essential too.