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. 

What is air made of?

Air is made of 21% Oxygen, 78% Nitrogen, .7% Argon and .3% carbon. What air filtration is concerned about is the filtering out of particulates and gases that are floating around in the air besides the mixture of gases that compose air. The contaminates in buildings come from building materials, furniture, people, processes and natural causes. The following image shows what exactly is floating around in the air you breath.  Note one micron is one 25,000th of an inch!

About This Blog

This blog is about educating the consumer about air filtration.  Clean air is something we take for granted.  I want to shed some light on how air is cleaned in buildings.  Once a week I'll post a new nugget of information.  We'll cover everything from Merv values to Hepas.  If you have any questions, post below.