Nevermore and temperature control

[Jonathan H]

I'm looking into building enclosures for our backspace (not for Vorons as yet unfortunately, but hopefully one day) and one thing we would like is filtering, because poisoning your members is frowned upon apparently.
The Nevermore filters came up in my search, and they look good, but the design does raise a question.
They are designed to recirculate the filtered air back into the enclosure, which gives better filtering, which makes sense, and it helps to prevent heat loss which is very useful when you are using a material that benefits from a warmer chamber, like ABS.
But what about for materials that work better at lower ambient temperatures, like PLA?
I've never printed with an enclosure to date, but I often see comments from people saying they leave the doors of their enclosures open when printing PLA, but then that would completely negate the filtering.
To me, if you. can't vent to the outside world, then at the very least you should be passing it through a filter, but the nevermore filter doesn't allow that, in fact none I've seen lets you switch between recirculation and extraction (I've found one that is offered in two versions, but none that does both).
Is this a non-issue? If not then has anyone come up with a good solution?

 

[Sanity Agathion]

Problem with PLA is, that it has very low temperature resistance. If you print enclosed, you risk filament softening right in the extruder, leading to jams in extruder and clogs in heartbreak.
Maybe you can create something in the style of fume hood? Where it will be open, but air being sucked to outside,
Don't skimp over room air cleaners either, they can be useful in eliminating VOCs as well.