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Where is the Air Filter in My HVAC System?

Learn where the air filter is in your HVAC system so you can change it in a breeze.

April 25, 2023

Bravo for wanting to change your air filter! That’s the first step to improving the air quality in your home, helping your HVAC system run more efficiently and saving money on energy costs. Because your heating and cooling system is one of the largest appliances in your home, proper installation and maintenance are crucial to keeping your system running properly and maximizing energy efficiency and cost savings. While some maintenance requires professional assistance, changing your filters regularly is a smaller task (with a big payoff!) that most homeowners can do on their own.

Why Do I Need to Know Where My Air Filter and Furnace Filter Are Located? 

Homeowners must know where their air filters and furnace filters are located so that they can be changed regularly. The United States Environmental Protection Agency (EPA) recommends that homeowners should check their air filter every month and change it at least every three months. Pet owners and allergy sufferers may consider changing their filters monthly. Air filters and furnace filters must be changed regularly for these reasons.

1. Changing your air filters makes the air in your home cleaner and better for your health. 

Your HVAC air filter and furnace filter trap airborne particles, like pollen, dust, pet dander, and smoke, before they enter your HVAC system so they stay out of the air you breathe. A clean air filter can bring relief to allergy and asthma sufferers and is effective at removing larger particles like dust and spores from the air.

2. Regularly changing air filters can help your HVAC system be more efficient. 

Contaminants like dust, dirt, and animal air can clog the coils in your HVAC system and limit the system’s efficiency. A dirty air filter means that your HVAC system will need to work harder for longer to produce the same amount of clean air, increasing your utility bill and decreasing your HVAC system’s efficiency. 

3. Changing air filters and furnace filters can extend the lifetime of your HVAC system.

Just like your vehicle requires regular oil changes, your home’s HVAC unit needs regular air and furnace filter replacements. When your air filter is dirty, it creates an added strain on your system, making the fan motor more likely to overheat and burn out. Keeping your air filter clean can increase the longevity of your entire HVAC system.

Watch this video to learn how to easily change a furnace filter.

Where to Find Your Air Filter or Furnace Filter 

Air filters and furnace filters are different products, even though they share the same functionality. Air filters clean cooled air and furnace filters clean heated air. Furnace filters are commonly found in the blower compartment of the furnace, usually located in a tray or door on the blower compartment. Usually, the air blower is located in a central location in your house, often close to your air intake vents.

However, finding your air filter can be more tricky. It may be difficult to locate on some HVAC systems, but you can usually find the air filter in the return air duct. Or, in layman’s terms, that big metal grate on your wall, floor, ceiling, or utility closet door. Return air ducts can be just about anywhere. Unlike the smaller ducts around your home, the return air duct or blower compartment pulls in the air from your home and sends it to your HVAC unit to be heated or cooled. It’s important to have a good air filter installed to trap allergens and other irritants so they don’t get circulated around your home.

Here are some of the most common locations for an HVAC air filter.

Your air filter may be in front of the fan.

Air filters are furnace filters are commonly found in front of the fan on the unit. This location helps stop any kind of debris from entering your HVAC system. The furnace filter will cover the entrance to the fan to protect your system from blockages. 

Duct openings are common places for air filters. 

Older systems may have an air filter installed inside a duct opening. Typically filters that are installed in duct openings are installed upstream of the air handler. Furnace filter are often installed inside duct openings to keep them out of sight. 

Your air filter may be in or behind the return air grill opening.

To see if it is there, remove the grill cover (either by removing the screws with screwdriver or pulling the levers) and reach inside to pull out the air filter. 

Air filters are commonly located between the return duct and the air handler. 

If you still have not found your air filter or furnace filter, look between the return duct and the air handler. The air handler is a large metal box that houses the fan and its motor. To see if the air filter is in there, find the grill opening that pulls air into it (called the return duct). Search between the return duct and the air handler to see if an air filter is located between the two, where the air handler and return duct meet. 

Your air filter may be in a basement, attic, or the back of a closet. 

If you have not found your filter in a duct, the air handler, or grill openings, check the less occupied areas of the home including your basement, attic, or even the back of a closet. Search for a slot about one inch wide with a hinged cover or removable cover. 

Where to Find Air Filters in Different Types of HVAC Systems 

  • Horizontal HVAC units – Horizontal units are frequently located in attics, large basements or garages. The filter usually fits in a slot on the air return side of the unit.
  • Vertical HVAC units – These systems are usually found in smaller basements or crawl spaces where space is limited. The filter typically slides into a slot above or below the HVAC unit.
  • Other HVAC systems – For any other kind of system, look for the air filter behind the return air grill on the wall, ceiling or utility closet door.

Don’t forget, some HVAC systems have a return in each room. So there may be an air filter behind each of those return grills.Finding your air return ducts can be a bit like a scavenger hunt. But it’s worth the effort to walk around your entire house, looking high and low. Be sure to check behind doors and other hidden places, so you don’t miss one. Still need help finding it? If you’re stumped, don’t hesitate to schedule an appointment with your local Trane dealer. They can help you locate your air filters and show you how to change them, so it’ll be easier next time!

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