What does an air handler do?

An air handler is a piece of your central HVAC system. It attaches to your air conditioner, furnace (or heat pump), and plenums, leading to your ductwork.

Your air handler takes the warmed or cooled air created by your HVAC equipment and blows it into the supply plenum, which connects to your air ducts. Your ductwork distributes the treated air throughout your home.

Your air handler also connects to your return plenum, which takes air from inside your home and brings it into your HVAC system. Depending on the season, the air handler pushes that air to either your air conditioner or furnace, where it’s heated or cooled.

On the outside, an air handler is a large metal box that looks similar to your furnace. It’s typically installed alongside your furnace in your garage, attic, utility closet, or basement.

Parts of an air handler

Your air handler moves treated air through your home using the following components.

Blower motor

The blower motor powers a fan that pushes air into your ducts. It also helps circulate air from your home back into your AC or furnace.

Blower motors come in single-speed, dual-speed, and variable-speed varieties.

Single-speed blower motors can function at only one setting. These are typically less expensive upfront, though they’ll cost you more on utility bills in the long run.

Dual- and variable-speed blower motors can adjust automatically to different speeds. They’ll keep your home more consistently comfortable. They’re a bigger investment, but they’ll save you on utilities over time.

Evaporator coil

Your compressor is part of your outdoor AC unit (the condenser). The compressor pumps refrigerant into the air handler’s evaporator coil.

When the blower motor’s fan moves air over the evaporator coil, it cools the air. As the refrigerant warms in the coil, it gets pushed back to the compressor to cool down again.

Air filter

Your air handler’s air filter is on the return side of the unit. It filters air entering your HVAC system from your home. 

Air filters remove dust, mold, and bacteria from the air. This improves your household air quality and also protects your HVAC system.

Electrical components

Your air handler contains electrical components, such as a contactor and relay board, that help it do its job.

One notable electrical part is its emergency heat strip. The heat strip turns on when cold outdoor conditions make it difficult for your HVAC system to keep up with your heating needs. 

Common air handler problems

The average cost for air handler repair is $350. It may help to diagnose the problem yourself and try a few air handler troubleshooting tips before calling a professional to fix your system. 

Air handler is not turning on

Your air handler may be clogged due to a dirty air filter. Change your filter, dust the unit, and try again. 

If this doesn’t help, reset your air handler at your fuse box.

Blower motor is not working

The blower motor is a hard-working part of your air handler, so it’s often the cause of issues with the system.

Switch your thermostat to “auto,” “on,” and a few degrees higher or lower to see if that will start it working. The problem may be the connection between the air handler and the thermostat if it does.

If you suspect the motor is having trouble, turn it off at your fuse box. Remove the air handler’s cover and dust inside with canned air and a soft cloth. 

Air handler is short cycling

Check out our short cycling guide to fix this problem. You’ll likely have to clean out your system or repair your flame sensor. 

Air handler is leaking

If you feel air flowing out of the joints around your air handler, fix them immediately. This means treated air from your HVAC system isn’t making it into your home, causing your equipment to work harder than necessary (and raising your utility bills in the process.)

You can DIY fix air leaks with aluminum tape and duct sealant. 

Air handler repair help

HVAC.com has pages to help troubleshoot specific Goodman, Rheem, and Lennox air handler units. 

If our tips don’t do the trick and your air handler isn’t working, call an HVAC contractor for help.

How much does an HVAC air handler cost?

According to the 2023 National Plumbing & HVAC Estimator, installing a new air handler costs between $3,662.90 and $25,820. HomeAdvisor suggests most homeowners pay far less than that at $2,450.

An HVAC air handler’s price depends on its capacity, features, and blower motor style.

How long does an HVAC air handler last?

Air handlers have a useful life of about 10-15 years.

Call us if your air handler keeps breaking down, and you suspect it’s time to replace it. We’ll match you with a licensed local HVAC dealer who can help you find the best new air handler for your home.

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