I posted earlier, but basically I'm transforming a portion of my turtle tank's stand (built myself) into my ball python's enclosure as well. A partition between the "storage area" of the stand (canister filter, misc supplies) was put in, along with a sheet metal ceiling and floor. I will put a piece of plexiglass with a hinge cut on it on for a door, making sure all escape paths are eliminated against, and then covering the walls with concrete-coated styrofoam for a rocklike background, as well as covering the floor with lizard liner or another astro-turf-ish substrate.
The idea is to maximize currently unused space to make a 33x19"x16" enclosure for my ball python, as an upgrade from the 20L tank he's in now.

My main concern here is ventilation. I am planning on putting 5 or 6 quarter-inch slits across the majority of the 28" wide door with a jigsaw to allow air transfer.

How much more do you guys think I need for ventilation? Are fans really necessary? Ventilating the right side isn't really an option because it only would ventilate into the other compartment in the stand, where my canister filter is - the screen is there because the heat bulb mounts on the other side, so the screen is to prevent the snake from burning himself.

For the BP enclosure that I built out of polycarbonate: I installed 3 small (1 1/2") ventilation holes with screens in the front left side and three on the right side wall near the top. There's a good angular draw of air. I don't think a fan is necessary. For my terrarium this is plenty. (I'm not sure if that is helpful for you or not. )
Here's a pic:

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Andrea

I think those slits should be enough. Your doors are not going to be sealed very tightly so you'll have ventilation there as well.

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Mike
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