Professional laser systems usually have cooling/heating elements built inside the projector. Although these are meant for keeping the laser modules at operation temperature, the climate inside the laser device needs to be quite balanced.
If you place a laser projector next to a fog machine or next to the air condition outlet (or even to the normal ventilation system) there may be a condensation of water/liquid inside the housing due to the temperature difference. The effect is comparable to the situation if you come from a cold outside into a warm room and your glasses fog up.
That's why it is very important to place the laser system appropriately and to avoid any situation that may raise the risk of condensation.
Condensation inside a laser device may lead to short-circuit of the unit and crash of laser diodes.
Please consider the operation temperature stated in the user manual of the laser system!
A Sealed Housing technology enclosure does not prevent condensation! Please head for a even more professional system (e.g. RTI NANO or SwissLas HighEnd) to reduce the condensation risk.