Currently, i have a 16x25x1 filter in my furnace/ac duct (probably a better term out there).
I am at the local store and they seem to be all sold of all brands of 16x25x1. They do however have an extensive selection of 16x24x1.
Would using the 1 inch smaller be ok or could this be detrimental to my furnace/health? Thank you
Best Answer
Filters only work if the air has to go through them. The filter has air resistance and a gap doesn't, so if you leave a 1" gap, a disproportionate amount of air will flow through the hole, effectively making the situation even worse.
If it is a choice of a smaller filter or nothing, at least do something like glue or tape a cardboard filler piece to the filter to make up the right size. The smaller filter area will behave like a filter that is already partially dirty, but you could use it temporarily.