How to Clean AC Evaporator Coils Inside House?

ResidentialCalendarJanuary 18, 2019

If you’re like many homeowners, you’ve never even heard of evaporator coils. So, it’s highly unlikely that you’ve wondered how to clean AC evaporator coils inside your house before. But when you find your AC is running less efficiently or if it’s stopped working completely, evaporator coils in need of cleaning are a likely suspect.  

In this article, we’ll go over what exactly AC evaporator coils are, what they do, and how you can better maintain and clean them to keep everything cool. We’ll walk you through the steps and options for cleaning the evaporator coils yourself, and help you know when it’s time to call in a professional technician. 

How to Clean AC Evaporator Coils Inside Your House

The first step in cleaning your evaporator coils is knowing how to access and recognize them in the first place. What does an evaporator coil look like and where exactly is it located?  

An AC evaporator coil for a central air system is a pyramid-shaped or A-frame network of copper coils. It sits inside a metal covering in the part of your AC unit that’s inside your house.1 The metal casing containing the AC evaporator is usually stashed away in a closet, in the attic, or somewhere else out of sight.  

AC units don’t actually create cold air. What really happens is that the evaporator coils capture the hot humid air inside your home and get rid of it. The coils are filled with a flowing refrigerant fluid that collects hot air and absorbs moisture. So, cool and dehumidified air is what’s left in your home. 

Once the evaporator coils collect the hot air, they remove it from your home by sending it through your air ducts to your outdoor AC unit. This outdoor unit has a compressor that acts as an outlet for the hot air your evaporator coils are removing from your home. It releases the hot air outside in a continuous process until your home is cool.2

Why Clean Evaporator Coils Are Important 

As you can see, the AC unit is an amazing and complex machine. It can help keep the air in your home comfortable, even in the hottest months of summer, as long as it’s well maintained. In order to prevent dirty evaporator coils from slowing an AC system, they should be cleaned regularly. 

It doesn’t take much for evaporator coils to get dirty since the air inside a home is naturally dusty, especially if there are furry pets in the house. Since AC evaporator coils dehumidify the air as well, they’re often slightly damp and collect dirt, dust, and pollen more easily. 

Even a thin film from this dust and dirt can cause an AC system to be less efficient, meaning a higher energy bill and less available cool air in your home.3

More potential problems with dirty evaporator coils are that ice could form on the coils. This literally freezes the process up and further dampens efficient AC energy usage. Since the air conditioner uses more energy than most appliances in your house, it’s important to be sure that it’s working at top efficiency. 

Ultimately, dirty evaporator coils could cause enough extra strain on the system that the AC unit could break down and stop working long before its expected lifespan. 

Steps to Cleaning AC Evaporator Coils 

The most basic way to keep evaporator coils clean is to make sure your AC unit has clean air filters installed. The air filters will capture most of the tiny debris that could cause trouble for your system.4 Though regular cleaning will still be necessary, the coils will be much cleaner if the air filter is cleaned and replaced when needed. 

Although you could have a professional HVAC technician take care of this cleaning process for you, here’s a quick guide for the DIY die-hards:

  1. Turn off the air conditioner at the thermostat.
  2. Wear protective goggles to keep dust, pet hair and other particles from getting into your eyes as you clean.
  3. Locate the access panel that allows you to see the evaporator coils (refer to your AC owners manual if you’re not sure where this is) and remove the screws holding it in place. Put them in a jar or somewhere safe so you don’t lose any. 
  4. Start by using a soft brush to clear away dust and buildup. 
  5. For removing finer pieces of debris, use a soft cloth to wipe it clean.
  6. Use a can of compressed air or an air compressor if there are stubborn particles, or if you simply want to ensure a thorough cleaning. Apply the compressed air evenly across the coils at a 90-degree angle.
  7. In addition to these methods, or separately, you can also apply a self-rinsing foam designed precisely for this cleaning process to the evaporator coils. Make sure you get a brand that is used specifically for cleaning AC evaporator coils and that it’s safe to use on plastic components.5

That’s it! You can do some or all of these steps every three months, or even as often as every month if you want a really efficient system. 

What happens if you go through the cleaning process yourself, but you’re still not happy with the results? Do the coils still look a little dirty? Is there no noticeable difference in your energy bill or in how your AC system is running? You might need to call an HVAC technician to do a professional cleaning job. 

Even if you are happy with the results of your self-cleaning job, it’s a good idea to have a professional perform annual maintenance anyway. Not only can they do a thorough job shining the coils up, but they can also spot any other issues early on so that they can be corrected.  

The technician will typically:

  1. Replace air filters 
  2. Clean the coils 
  3. Check for leaks in the refrigerant inside the evaporator coils 
  4. Address any other issues with the coils that could turn into bigger problems down the road6

Interested in other ways to save on energy bills? Read this article on why your electricity bill might be high and how to fix it.

 

Endnotes

1-4 https://georgebrazilhvac.com/blog/what-is-a-central-air-conditioner-evaporator-coil
5 https://www.sobieskiinc.com/blog/step-step-guide-cleaning-ac-evaporator-coils
6
 https://www.energystar.gov/index.cfm?c=heat_cool.pr_maintenance

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