Hello smart people!

I'm going to install LED lighting in my sauna, so I already ordered waterproof LED strips, suitable for the saunas, got controllers and etc. All together 330W.
Now I need a power supply, and came across two options: €100 - 400W waterproof, or €27 - 400W non-waterproof.

My question is: how these two options differ internally? How waterproof power supplies dissipate heat? Is there any way to get the cheap one and make it water-proof by myself?

 

Most waterproof psus are plastic rated IP67 , there are some aluminium extruded types IP67 rated, i would get the waterproof type if you're going to immerse it.