How to Know If the Evaporator Coil in Your House Is Bad

Hunker may earn compensation through affiliate links in this story. Learn more about our affiliate and product review process here.
Image Credit: justocker/iStock/GettyImages

Hot weather in the summer months is already a nuisance, and cooling down from humid weather can be just as tricky. The next time you're thanking your lucky stars that air conditioners were invented, remember to thank your unit's evaporator coil specifically. If your air conditioner stops working and you're dealing with humid air in your home, don't be quick to blame your whole unit. Most likely, the evaporator coil in your house is bad.


What Is an Evaporator Coil?

An evaporator coil is one of the essential parts of an air conditioner. Located indoors, the evaporator coil, also called a coil or indoor coil, keeps the temperature in your home regulated throughout the year. The coil is filled with refrigerant, so when your air conditioning system draws air from your home across the coil, the refrigerant evaporates and absorbs the heat from the air.


Video of the Day

In the summer months, the coil is responsible for giving cool air and getting rid of moisture from the air. If the evaporator coil goes bad, then it will be difficult to achieve coolness indoors. Before your system completely fails, though, some signs will indicate a bad coil.

Frozen HVAC Equipment

One way you can tell if your evaporator coil is bad is by looking at your unit. If you notice frost on your equipment, then your evaporator coil could be bad. When the equipment stops operating correctly, the refrigerant will freeze condensation. If you see that your air conditioner is frozen, turn off your system immediately and contact a professional to look at your unit.


Air Conditioner Leaking

Leaks could also be another sign that your evaporator coil is bad. Although it's normal to have some air conditioner condensation from the cooling process, which is usually taken care of through the condensate line and drip pan, keep an eye out for excess water leaking. When a system freezes, it can also freeze the condensate line, and that causes excess moisture to overflow.


You can also have excess water issues if there is frost buildup on the coil. Since the coil is located in the home, you need to keep an eye out for excess water building up around your indoor unit.

Warm or Humid Air

Since an air conditioning unit works by removing humidity from the air, warm air should not be coming out of your vents when your unit is running properly. If warm air is coming out of your unit but your air conditioning system seems to be functioning correctly, it could be your evaporator coil that's not properly cooling the air.


There are a couple of different reasons your unit could be emitting warm airflow, though, so you should contact a technician. The technician will be able to run a professional diagnostics report on your air conditioner to see where the exact cause of your issue is located.

Unusual Unit Sounds

If your air conditioner is making unusual noises or working overtime to cool your home, your evaporator coil could be bad. When an air conditioning unit cannot access the evaporator coil's cooling properties, the unit could start making noises to signal that something is wrong. Several problems could cause air conditioning noises, though, so you'll need to contact a technician to run a professional diagnostics report to pinpoint the exact problem.




Report an Issue

screenshot of the current page

Screenshot loading...