How Often Should I Change My Furnace Filters?

540031 - FilterLock - Filter Slot Cover furnace filter slot cover Furnace filter slot cover that is an easy fix to HVAC air leaks Here's the link to AllergyZone furnace filter slot Usually, there's a plate that covers the air filter slot Image: An HVAC technician changing out an air filter Some HVAC systems don't have

birthday slot air filter and the two-piece system allows you to cover a filter slot up to 25 inches which is