I can’t find the air filter in the HVAC unit in the home we just bought. Do all central heating and cooling units have filters? -Paula

Hi Paula,

All central heating and cooling systems should have an air filter, but the filter can be harder to locate on some HVAC units than others. The air filter is usually located in the return air duct or blower compartment before the return air reaches the air handler. This allows the filter to clean the air coming from your house before it enters the HVAC unit.

Common locations for air filters in HVAC units include:

• On horizontal HVAC units with the return duct attached to the side of the air handler, the filter often fits in a slot on the return air (intake) side of the unit.
• On vertical air handlers with the return air duct entering on the top of the air handler, the filter often slides into a slot above the HVAC unit.
• On vertical air handlers with the return air duct entering below the air handler, the filter often fits in a slot located below the HVAC unit.
• On other HVAC systems, the air filter may be located behind the return air grill on a wall in your home.
• On HVAC systems with a return in each room, there may be an air filter behind each of the return grills.

Good luck with your project,

Further Information

• HVAC System Heating and Cooling Maintenance Tips (video)
• How to Choose Air Filters to Reduce Indoor Air Pollution (article)
• Choosing Air Filters for Your Home (video)

Tags: , air filter, cooling, duct, heating, hvac