These work excellent. I put a finer filter on the output. Clear difference in the pollen seasons, but I just let it run all year and swap the (visually clogged)

These work excellent. I put a finer filter on the output. Clear difference in the pollen seasons, but I just let it run all year and swap the (visually clogged) input filter every few months. The FPR10 output filter lasts longer, but you gotta take a look at the side facing the fan to inspect it. Also, consider adding output filters on any AC units (ducting etc). Even a "new" AC system can quickly become a source of particulates, or (way) worse.