A lot of people have problems with humidity and heat retention with visions. However this is a common problem with every cage. Each enclosure needs to be for the lack of a better word tuned to the animal within and the enviroment in which its kept.
For example visions are notrious for being over ventalated, but it's easier to block excess holes than create more. The same goes for heat.
Visions are made of a thin polyethelene very durable but thin which doesn't prevent heat transfer.
This is bad in a low temperature room like a bedroom.
Again this can be tuned by adding insulation below the cage and closing off some vents.
In regards to humidity, using a moisture absorbant substrate such as cypress or even aspen will retain some moisture. As well as moving the water source closer to the heat source to increase evaporation within the enclosure.
All cages require tuning....no matter what someone says, however some take more effort than others.
Good Luck
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Jeremy Payne
"I am become death, the destroyer of worlds" July 16, 1945 Robert Oppenheimer
1.0 Snow "Khal"
0.2 Triple Het Moonglow "Khal"
0.1 Orange Tail Hypo Het Leopard
1.1 Double Het "Sharp" Snow
1.0 Ghost **coming soon**
0.1 Possible Super Hypo
0.1 DH Ghost **coming soon**
1.1 Khal Albino
1.0 Hypomelenistic
1.3 Pastel Hypo
0.1 Suriname/Columbian cross
0.1 Anerthrystic
1.1 Cream Golden Retrieviers
1.0 Pomeriaian
0.3 Catus Terribilis
0.1 Spouse
2.0 Child