On 7/12/2020 1:44 PM, johnny wrote:
replying to chuckk, johnny wrote:
I have the same thing - a 20x25x5 slot, but those filters are very
expensive.
I found a better deal on filters 20x25x4 (1 inch smaller). I plan on just
using these. When the furnace/airconditioner starts up, I expect it will
just
suck it into place (since there is 1 inch of "play"). Alternatively I might
build a small 1 inch shim to stick in there. The different websites make it
sound like rocket science, but I bet this will work just fine


Better deal but less filtering surface. Less surface means more
frequent changes. False economy.