Is a 23x20x1 Furnace, AC or HVAC Filter the same as 20x23x1? This is a question we get often, we also get a lot of returns because of this. Not only for this size but for all air filters where the larger dimension is printed first on an air filter.
The short answer is yes 23x20x1 is the same as 20x23x1. They are the same if that is the true "exact" size of your air filter. Since an air filter is a rectangle (or a perfect square) it's just a matter of how you're holding the filter, length or width.
This is where it can get confusing - Typically if someone is searching for a filter that is 23x20x1 and it's printed that way on an existing filter it's most likely what the industry calls a "grille" cut filter. The size printed on the filter is the rounded, nominal measurement. While the true exact size of the filter if you were to measure it with a tape measure is probably going to come out to something very close to 22-1/8 x 19-3/8 x 1 or 3/4" depth. In some instances you might find the actual size printed on the filter in smaller print.
Best advice we can give is don't assume the size printed on your filter is the "exact" size, it's most likely the nominal rounded size printed on it. As the old adage goes, measure twice cut once.
Popular filter option: 23x20x1 "Grille" MERV 8 Rated Air Filter
If you still have questions regarding air filter sizes please let us know, we would be happy to help.
