Protect Your HVAC With A Filter Slot Cover - Filter Lock

Where's the Furnace Filter? Multiple return registers: Look for an air handler with a slot and removable cover where the filter sits

A lot of HVAC air handlers do not have covers over the filter slot and this is costing homeowners

furnace filter slot cover An HVAC professional can retrofit such a filter to your current ductwork if you don't already have a slot that can hold a 4-inch filter

wat is doornmaat slot Furnace filter slot cover that is an easy fix to HVAC air leaks Here's the link to AllergyZone