I ordered a 14x22x1 because that's what's wrote on the furnace, it was just a bit to big and I had to make it fit, now I'm sure it has nothing to do with the filter since I've had difficulty since moving in.
While I really wanted to love these I don't. The Filter Buy filters measure 3/8" shorter than the name brand filters I bought them to replace. In many installations such a small difference will make no difference at all. In my overhead location 3/8" shorter means that the filters fall out and I now have to tape them in place. I will continue to use them because of the huge cost savings, but only until I find another brand that isn't nearly an inch shorter in each dimension than their stated size. Yes the actual size is listed in the detailed description but I wonder why their filters measure shorter than every other brand I've ever purchased.