Why is my furnace filter slot larger than the manual's spec?
I have a Lennox Elite Series G24M furnace installed as up flow. The manual says that it requires a 16x20x1 air filter but the slot that is present fits a 16x20x4 filter. These filters are extremely hard to find in store. I am confused as to why the installers
The tinners who installed your ductwork installed a higher quality filter than the furnace manufacturer specified, which is a good thing. Talk to the contractor, or any Lennox distributor near you, and buy one filter. When you have the number, you can