Heating, ventilation and cooling (HVAC) systems do more than just regulate indoor temperatures; they clean the air by removing particulate matter. All central HVAC systems have a main air filter. You can typically find it inside of the furnace next to the blower assembly. When running your HVAC system, the air filter will remove dust, mold, pollen and other airborne pollutants.
Some HVAC systems, however, have return air filters as well. They still have a main air filter inside of the furnace, but they have additional air filters for the return vents.
What Are Return Air Filters?
Return air filters are exactly what they sound like: air filters for the return vents in a home. They are available in the same materials as standard, furnace-installed air filters. You can find return air filters in fiberglass, pleated paper, polyester and other common materials. Return air filters are simply designed for use in return vents.
Advantages of Return Air Filters
Using return air filters can promote cleaner ductwork. Return vents are air vents that create a suction force. Your HVAC system will draw air from your home’s indoor spaces through the return vents. Return air filters will clean the air before it reaches your HVAC system’s equipment and the ductwork.
Return air filters are easy to access. They are installed directly behind the return vents’ grilles. You can typically access a return air filter by unscrewing and removing the grille.
Disadvantages of Return Air Filters
Like other air filters, return air filters must be replaced. The longer a return air filter goes unchanged, the dirtier it will become.
Failure to regularly change return air filters will restrict your HVAC system’s airflow. Your HVAC system won’t be able to pull enough air to cool or warm your home’s indoor spaces. To prevent this from happening, you’ll have to change your return air filters every few months.
Another problem that can occur if you don’t change return air filters is mold. Return air filters are found behind the vent grilles. Over time, dust may accumulate on them while paving the way for mold.
Most homes don’t need return air filters. The main air filter will suffice at removing pollutants from the air. Air must still travel through the main filter before entering your home’s ductwork. As long as you use a high-quality main air filter – and change it every few months – you shouldn’t need return air filters.