Where Is My AC Filter Located and How Do I Change It?

Is the AC inside your home running a bit warmer than usual, but the number on the thermostat remains the same? Is 90 degrees starting to feel like 110? It might be time to replace your air filter.

Replacing the AC filter in your home will allow the unit to keep blowing cool air without interruptions. If the air filter becomes clogged with debris and dust particles, causing an airflow restriction. And, eventually, the clogged filter can lead to unit repairs, a higher electric bill, and a lower lifespan on your unit.

The good news is that replacing the filter on your AC is a simple task— once you know how to find it.

In this blog, we’ll show you how to locate your AC’s filter, the steps to change it, and any problems you might face when changing your filter.

The air filter is typically near the thermostat in your home in a return duct. Or, it's most likely right next to your AC system’s air handler.

For most units, the filter’s location is at the point where the return duct enters the air handler. But, in case you have a unit with one and not the other, here’s what each will look like:

This AC has a grate located on the ceiling, wall, or floor and contains slatted openings for air to flow through. They are usually larger than a standard air duct vent.

One tip to determine a return vent: hold your hand or a piece of paper up to the vent while the AC's fan is on. If the paper gets pulled toward the vent or you feel a suction effect, it’s a return vent.

The air handler is a large metal box that stores the AC's fan and motor. You can typically find it inside the attic or basement.

When you find it, the replaceable filter is on the unit's left side, right side, top, or bottom.

One tip about your air handler: The filter may fit in a small slot with directions demonstrating how to insert the filter. Air handlers often need to be unscrewed by hand or with a tool to access the air conditioner filter.

Once you locate either system, look for a slot where an air filter should fit. Larger houses may have more than one system and will have separate filters for each system.

Now that you know where and how to locate your AC’s air filter, use the following steps to change it out:

• First, know the size of your filter. Each unit should have the filter size located on the previous filter. If you are uncertain about the size, grab a measuring tape and measure the height and width, or look for the manufacturer’s name and locate the size on their website.
• To remove your old filter, turn off your AC, unscrew your air handler or grate from a return duct and gently pull it out. If the filter is dirty, wrinkled, greyish, or filled with dust — its next destination is the trash.
• Be sure to place the new filter in the same direction as the old one. Follow any instructions printed on the package of the new filter.
• Arrows usually show which direction the air pulls, and you’ll want the air to pull into your system, not away from it.

In the process of replacing the filter in an AC system, you might discover a few areas that look unusual.

When you pull out the old filter and see an excessive amount of dust and debris surrounding the ducts or the space behind the filter, that's a clear sign that you have clogged return ducts. If the return ducts have too much dust, some rooms in your house may have limited airflow and more dust settling on surfaces.

Want to learn more about ducts and the benefits of cleaning them? Read our blog, “3 Benefits of Having Your Air Ducts Cleaned.”

If your air handler has water around it, a few things could be at fault:

• A leaky drain
• A clogged condensate line
• A frozen evaporator coil

When these issues occur in your home, you’ll need a professional to diagnose and restore your unit to life. Start with maintaining your AC’s filter, and we’ll help with the rest.