When you are buying air filters for your central heating and A/C method a single thing a lot of folks do not realize is the fact that you need to get the right fit and size for whatever it is that your air filters are inserted to. There are so several weird shapes and sizes when it comes to air filters for central heating and A/Cs. It could be that you may need a single air filter that is smaller or love our central heating and A/C, you need several air filters that are rather large. That is the way it consistently varies per heating and cooling set up in your beach house when it comes to air filters. I l received this just a few weeks ago when I moved into a new beach house that had this untypical air filter set up on the central heating and A/C. I had never heard of having 2 big air filters before. It goes to show how much I know. It may be because this central heating and A/C method puts out more grime and dust than others? I have no method to tell you the truth. All I guess is that I have to buy 2 truly big air filters each time, do not ask me what the dimensions are because I have them written down somewhere and I look at it every single time I need to buy more air filters for our central heating and A/C method unit. So consistently check the size of the air filters that you may need before buying them for your HVAC unit.