There’s actually lots of venting and filters on the back, as well as the rear of both sides. The problem I see is that a TEC works by generating heat on one side and cold on the other, it’s basically a series of solid state transistors. The hot side is in the back with the fans and heat sink. The issue is that a TEC will only generate a difference of about 20f, so insulating the box better will allow it to run a bit more efficiently, but it still will not make it get colder. From everything I’ve read on TECs the only way to make them run colder on the one side is to dissipate heat more effectively on the hot side. I think it would be more efficient to increase cooling to the rear with more air flow like larger fans or a bigger heat sink. Not saying it will hurt anything to try and see what happens, just giving my best guess as to the results. Here’s a couple pics of the rear and side vents.
The rear with vents and filters for the fans
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Here’s the side with vents as well
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