ASHRAE's publication, Guidance for Building Operations During the COVID-19 Pandemic, recommended MERV 13 as a minimum value when selecting air filters for general building ventilation. The CDC referred to that same document in their guideline ; Ventilation in Buildings.
One result from those publications is many end-users, perhaps for the first time, are being forced to evaluate their air filtration program and the capabilities of existing HVAC systems. Many have been forced to confront the realities of MERV vs. MERV-A as outlined in another ASHRAE document: Filtration/Disinfection.
In response, Camfil has launched an online tool that uses questions to identify air filtration goals and determine basic system capabilities. The link below can be forwarded to your customers or you can sit down and go through the options together to arrive at the solution that works best for them.
Special thanks to Camfil's Michigan Branch Manager, Andy Zook, who originally developed and used his own version to assist customers struggling to make the best decision for their organization.