MERV filter guidance issues

[jeffkaufman]

https://www.microcovid.org/blog/hepafilters currently says:

Central heat / AC systems don't work for this. These typically use MERV-rated filters. These are significantly less effective at removing small particles than HEPA-rated filters (the best MERV rating, MERV-16, merely removes 75% of particles.

MERV-16 is rated at 95%, not 75%: https://www.nafahq.org/understanding-merv-nafa-users-guide-to-ansi-ashrae-52-2/ Maybe you were thinking of MERV-14's performance in the 0.3-1 micron range?

Even then, doesn't it depend on airflow? A lower-filtration option should outperform a higher-filtration one if the flow difference is large enough.

[jeffkaufman]

doesn't it depend on airflow? A lower-filtration option should outperform a higher-filtration one if the flow difference is large enough.

Lots more on this now: https://www.jefftk.com/p/merv-filters-for-covid

[apiology]

@beshaya, you had written the original article - curious for your thoughts on this.