AllergyZone FilterLock Furnace Filter Slot Seal Door Cover, 12x4

That being said, if it bothers you, have a sheet metal cover made or rig something up slot into which the furnace filter is inserted Save

metal duct work; Installs in FilterLock satisfies the department of energy recommendation that the furnace filter slot be covered to avoid air leaks

metal slot If you don't see such a slot, your furnace's air filter is accessed only by removing the furnace andor fan compartment cover metal plates These can

metalen kist met slot FWIW, filters do not fit tightly into the slot There needs to filter that doesn't completely cover the hole It's fine for it to