I was overwhelmed looking at all of the available a/c 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 Heating, Ventilation, and A/C 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 myself and others that the basic differences between filters is in the level of absorption they have of air contaminants appreciate dust, pollen, and mold spores. Your most basic filters can only handle dust and pollen while some of the most upscale 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 observed some filters and whole-house air purifiers in the store flaunted 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 typical filters. And anything sold as a “HEPA filter” easily has to meet regulatory standards set forth by a collective of varying governing bodies and entities, so if you buy 1 you think you’re getting a guaranteed product. Hospitals use them, nursing homes use them, and people with asthma and pollen irritations are encouraged to use them as well. I have troubles with both from time to time so I figured I’d supply the HEPA filter a shot despite the price, and boy am I cheerful 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.