Who is Merv?

MERV stands for Minimum efficiency reporting value.  The higher the MERV value the smaller the particle it can filter out.  Have allergies?  Use a MERV 8 filter and you will filter out most mold and spores.  If you go up to MERV 9 then you start filtering out auto emissions.  At MERV 15 you can filter out most tobacco smoke.  The scale tops out at MERV 16.  After MERV 16 you cross into a new type of filter, the HEPA.  The HEPA filter will be the topic of our next conversation.  The following Chart shows the MERV scale and what each MERV rating will filter out.  Note at the bottom, Residential system modification may be necessary for filters greater than MERV 8.  This is due to higher energy demands on fans to push air through filters with MERV values higher than 8.