Blue Pure 211+

+1 to CR boxes, I ended up building https://www.texairfilters.com/an-easy-to-build-corsi-rosenthal-box-using-modular-pc-fan-systems/ and prefer it over my Blueair Blue Pure 211+ I bought in 2020. r/crboxes exists too.

Ive read that the difference is negligible but I’ve not seen independent testing to confirm. There has been testing on Blueair 211 that shows the ionizer contributes to between ~20-50% of the measured CADR (the range is because it depends on particle size) which makes me sceptical that it’s negligib

There is more to Blueair 211 filter that is a fail in my experience. There are 2 layers to the white fabric material. The pleated material is rigid and has a second layer of material adhered to it. This is very fine and looks HEPA grade as I cannot see pinholes. Blueair is named in a Hepa filter law

Blueair comes with ionizers, though, which is bad for your health and can cause respiratory issues. HouseFresh wanted to see what would happen if you removed the ionizer from the 211+, and almost half of its performance was gone. Which shows its filters aren't actually that good and mostly relies on