This Sunday I decided to replace all the air filters throughout the house. The A/C guys told me to do it monthly or when you can no longer see the “blue” in the color. So I waited a few months and changed them this weekend. I have a new house, and the A/C is pretty new also, they put in about 4 of these air filters throughout the house.
So I went to the local hardware shop, same place I bought the foam sealant and told the guy there, I need air filters. I told him, I had the blue ones and asked him why are there so many different types. He said, funny I ask, cause he was watching one of those “do it yourself” shows on TV and the guy said, if you can see through the filter, then don’t buy it. The blue ones, you can see through. Here is a very nice picture of what a clean blue filter looks like:
If you hold it facing you, typically you can see through it. Most of the filters I replaced, 3 of 4, were fairly clean. The one in my bedroom was completely dusty and filled with stuff.
I purchased something more like these:
They are white, pleated and you can’t really see through them.
In order to write this up, I decided to check out EPA’s Guide to Air Cleaners in the Home. The guide basically recommends anything above “MERV” 7 or so. I know the ones I ordered online for my bedroom are MERV 7. My bedroom is a weird size and non of the local stores had the size in. EPA said, “filters with a MERV between 7 and 13 are likely to be nearly as effective as true HEPA filters.”
So, I guess, MERV 7 or up is the way to go. Depending on which one you get, it says how often you should change them. Most people let the filters go through the summer and change them annually. I think that is what I will be doing.