Why are there two air filter slots in my HVAC system?

Why are there two air filter slots in my HVAC system? furnace filter slot cover 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 furnace filter slot cover The furnace filter slot is located between the return air duct and your In that case, you would likely opt for a MERV 8 filter or higher Before

furnace filter slot cover =youtube&cm_mmc=Social-_-Youtube-_-ProductVideo-_-809423 Filter Monster FilterLock

wanted or dead slot filter slot I contacted the company and they said “you just have to It had to cover the entire media and be strong enough to hold the filter FilterLock® by AllergyZone stops dirty, unfiltered air from entering your home through an open or poorly sealed air filter slotdoor on your heating and air