i can't imagine these perform worse than something like pic related. i have one just like this and i've not changed the filter in like 6 years, but it does have a pre-filter that i take out and rinse off. it's mostly for white noise to keep the tinnitus away.
the problem is that a box fan with HVAC filters taped to it looks like shit. i can have pic related in my room and not look like a broke nigga