I was overwhelmed looking at all of the available air conditioner filters when I was at my local hardware store last week. Once I had determined the size of my filter tray, which in my case is 20 by 20 inches, I finally had to choose a brand and style of filter. But since this was my first time owning my own place and having to finally buy an HVAC filter myself for the first time, I was confused and unsure of what to buy. I asked the heating and cooling expert at the hardware store and he told me that the basic differences between filters is in the level of absorption they have of air contaminants like dust, pollen, and mold spores. Your most basic filters can only handle dust and pollen while some of the most expensive filters are dense and thick enough to filter out actual bacterial and viral pathogens on top of a whole host of varying particles that can theoretically swirl through the air in your home. I noticed some filters and air purifiers in the store advertised with something called HEPA certification. He said that this stands for high efficiency particulate air/absorption, and that essentially these filters have an ability to filter our air particles at a level far beyond that of most standard filters. And anything sold as a “HEPA filter” actually has to meet regulatory standards set forth by a collective of varying governing bodies and entities, so if you buy one you know you’re getting a guaranteed product. Hospitals use them, nursing homes use them, and people with asthma and allergies are encouraged to use them as well. I have issues with both from time to time so I figured I’d give the HEPA filter a shot despite the price, and boy am I happy I did. My breathing feels more seamless and less constrained and I haven’t had a headache since I put it in. It pays to get the right kind of filter for whatever your needs are.