The first time my husband, Justin, asked me to pick up HVAC filters for our home, I panicked. No, seriously. I had no idea what type to get (or what would happen to our HVAC system if I got the wrong one).

But I’m a Pacific Northwest girl. We don’t whine — we figure stuff out and then get it done.

So, after some research (i.e., conversations with the pros at Home Depot), I now know way more than I ever wanted to about choosing an HVAC filter. And just in case you ever find yourself in a similar situation, I thought I’d share what I learned with you.

For starters, HVAC filters are cataloged based on their Minimum Efficiency Reporting Value (MERV) ratings. There are four main types, and if you go to Home Depot, they’re color-coded for simplicity.

MERV ratings dictate the effectiveness of a filter. So, the higher the rating, the more effective the filter. The breakdown looks like this:

MERV 1 to MERV 4 (Green) – pollen, dust mites, standing dust, spray paint dust, and carpet fibers

MERV 5 to MERV 8 (Red) – mold spores, hairspray, dust mites, animal dander, and cement dust

MERV 9 to MERV 12 (Purple) – humidifier dust, lead dust, auto emissions, and milled flour

MERV 13 to MERV 16 (Black) – household dust and pollen, pet dander, outdoor pollution, mold spores, microscopic allergens, bacteria, most tobacco smoke, sneeze bacteria, and virus carriers

So… which one of these is appropriate for home use?

Well, the higher the MERV rating, the harder your furnace has to work. This means that as “efficient” as it may seem at first glance, grabbing a black filter isn’t ideal.

In fact, most people go with a MERV 8 filter (the green one) since most home HVAC systems can remove contaminants with this “low” rating. It’s plenty effective and stops your furnace from working overtime.

Of course, if you need any help choosing a filter, just let me know. I’m always down for a Home Depot run!