How To Clean Evaporator Coils On Central Air Conditioner

We may get commissions for purchases made through links in this post.

Central air conditioners are critical to summertime comfort. Unfortunately, the evaporator coils, which are essential to temperature exchange in the system, get dirty quickly. This leads to a loss of efficiency. Knowing this, you are wondering how to clean evaporator coils on central air conditioning systems. In this post, we combine industry professional knowledge and up-to-date research to answer your question.

To clean your central air conditioner evaporator coil, follow these general steps:

  1. Shut the power off to the system
  2. Locate your evaporator coil
  3. Determine if the coil needs cleaning
  4. Insert collection tray
  5. Clean the coils
  6. Reassemble and repower the system

Keep reading the rest of this post for details on each of the above evaporative coil cleaning steps. We include a few options for different cleaning techniques. To conclude, we’ll discuss when it is time to clean your coils as well as the answers to a few related questions.

A repairman clean compartments of air conditioner system, How To Clean Evaporator Coils On Central Air Conditioner

How to Clean your AC Evaporator Coils

The following steps include two ways to clean your evaporator coils. This technique does involve some basic handyman skills, especially when it comes to disassembling and reassembling your system.

If you are worried about accomplishing any of these tasks, or cannot find your evaporator coil, it is a wise decision to call an HVAC professional. They can fully service your system to ensure efficient heating and cooling.

1. Shut the power off to the system

Before anything else, and for personal safety, it is important to shut the power off to the system. This might seem a bit obvious, but even experienced workers forget this step from time to time.

Electrical panel

Sometimes, your indoor AC unit will have a switch that you can use to cut power to the system. However, it is also common that the only way to cut power is at the breaker box.

To test, you can try turning the unit on. If nothing happens as it usually would, the system is likely off.

2. Locate your evaporator coil

The evaporator coil is the last component in the indoor portion of your air conditioner’s mechanical system.

That is to say, the air passes through the filter and the fan before it reaches the evaporator coil. Often, it is as simple as removing the main indoor AC cover to expose the coil.

Air conditioner evaporator coil

Alternatively, if you still have the owner’s manual for your system, a clear schematic will take the guesswork out of finding the evaporator coil.

The coil is a combination of copper pipe, which holds the refrigerant and temperature distribution fins. These fins are very fine metal and look just like a car’s radiator.

The whole unit is shaped like a ‘V’ whose point is towards the direction of airflow. This can be up, down, or sideways depending on your system.

Sometimes, there will be a main cover for the interior unit and then an inner cover that fits the ‘V’ profile. As you take all covers off—and any other components like vents that are in the way—be sure to keep screws and fasteners in an easy-to-find location for later.

3. Determine if the coil needs cleaning

Now it is time to inspect the inner side of the coils. The inside of the ‘V’ is where the air first hits the evaporator coil, where any dirt and debris will collect.

Old evaporator coil

If you see any amount of dirt or hair build-up, it is good to clean the coil. If you do not see any dirt at all, it is okay to put off cleaning for another day.

4. Insert Collection Tray

The collection tray is a piece of cardboard, paper, or other material that captures any dirt and debris that falls from the coils as you clean them. Without a collection tray, a lot of dirt will fall into the system, leading to more frequent cleaning.

To make the collection tray, measure the inside dimensions of the bottom of the ‘V’ and use scissors to cut your tray to fit. This step is advisable even if the ‘V’ points sideways. However, if the ‘V’ points down, there is no need to make the tray.

Alternatively, or in addition, you can use a vacuum hose to carefully suck up dirt and debris as it falls off the inside of the coils.

5. Clean The Coils

Now it is time to get to the actual cleaning of the evaporator coil assembly. To begin, you can either use a stiff brush or compressed air. Following that, a cleaner is advised.

Stiff Brush

Click here for a brush designed for AC evaporator coils on Amazon.

A stiff brush, even like a stiffer paintbrush, works great to dust all of the dirt and debris off the coil fins.

Do not scrub so hard as to bend the fins, but do try to thoroughly remove any build-up. As everything falls onto the collection tray, the importance of that tray will be highlighted.

Compressed Air

Alternatively, or in addition to a brush, you can use compressed air to blow the fins clean. Point the air through the fins the opposite of the airflow.

As you do this, the debris will get blown every which way. So, to make the mess smaller, couple the compressed air with a vacuum to clean as you go.

Click here for an air compressor from Amazon.

Be careful—if you blow the air too forcefully or too close to the fins, you might bend them. Bent fins are less efficient than straight ones.

Further, since many homeowners do not have access to compressed air, it is fortunate that this part of the cleaning process is optional.

Use a Cleaner

There are many over-the-counter cleaning products sold just for cleaning evaporator coils. The wisest move is to purchase one of these specially designed products.

Click here for an AC evaporator coil cleaner from Amazon.

Usually, these are no scrub, working to break down grime on contact. Follow the directions on the spray can and thoroughly soak the inside of the evaporator coil. Once the product has worked into the coils, clean off with clean water from a sprayer or spray bottle.

Repeat the cleaning process until you find that no additional dirt is removed. The small cost in time and cleaner is well worth the additional efficiency this process will afford to your AC unit.

6. Reassemble and Repower System

Once you have cleaned and thoroughly rinsed the coils, you can reassemble the system. Do not forget to remove your collection tray.

Reassembling is as easy as putting all covers and other components back in the opposite order that you took them off. Once completed, repower and test the system to make sure everything is in working order. Congrats, you are all done!

What Should I do with bent evaporator coil fins?

As you clean your evaporator coil, you will notice that some of your fins are slightly bent. This is an issue because it decreases system efficiency. To fix, use a specialized fin comb to straighten the fins back out.

Click here for AC evaporator coil fin combs from Amazon.

How often should AC evaporator coils be cleaned?

Generally, it is recommended that you clean your AC evaporator coils once per year.

However, if you live in a dusty place, have lots of pets, or notice symptoms of dirty coils, you might want to clean them more often. The more frequently you clean your AC evaporator coils, the more efficient the system will run.

What are the symptoms of a dirty evaporator coil?

The first sign of dirty evaporator coils is you will notice a drop in system efficiency. This means that the AC will blow warmer air, will cycle on more often, might not cool the home, and might not even turn on at all.

Other signs include noises from the system, frost on the coils, refrigerant leaks, and water build-up.

If you notice any of the above signs, it is wise to take the time and check your coil to see if it is dirty. If dirt is not the problem, it is probably time to call an HVAC technician.

Is it worth replacing the evaporator coil?

Whether or not it is worth replacing the evaporator coil is a case-by-case decision. However, the general rule of thumb is no. If your evaporator coil fails, then the rest of the system is close behind.

In fact, the new evaporator coil will only be able to work as efficiently as the rest of the system. This means that you certainly will not get the most bang for your buck.

How much does it cost to replace an AC evaporator coil?

Generally, with parts and labor, it costs about $1,000 to replace an AC evaporator coil. This does vary based on local prices from about $600 to $2,000.

How do you clean an evaporator coil without removing it?

The instructions outlined above are how to clean an evaporator coil without removing it. In fact, you should never need to remove your evaporator coil unless you are replacing it or if an HVAC technician has a specific repair they need to make.

In Closing

In this post, we answered the question of how to clean an AC evaporator coil. We provide a thorough step-by-step written guide to this process which includes a few different cleaning strategies. To conclude, we answer several related questions. Good luck!

Before you go, be sure to check out these other posts:

AC Unit Freezing Up In The Summer – What Could Be Wrong?

AC Thermostat Keeps Shutting Off — What To Do?

Air Conditioner Outside Unit Freezing Up – What Could Be Wrong?

Leave a Reply