How to Clean AC Evaporator Coils Inside House (WITHOUT Removing It!)

In the summer, there’s probably nothing more inconvenient than an inefficient or a non-functioning AC. Oftentimes, dirty evaporator coils are the culprit.

AC evaporator coils are the components of the AC system that absorb heat inside your house and produce cool air via the condenser coil.


If the evaporator coils aren’t cleaned and maintained on a regular basis, the AC may struggle to remove heat from the air or even stop working altogether.

In this post, we’ll walk you step-by-step through the whole process of how to clean AC evaporator coils inside your house without removing them. So, let’s get started!

Step 1: Prepare the Necessary Materials and Tools

You’ll only need a handful of materials and tools to thoroughly clean evaporator coils:

  • A screwdriver
  • Evaporator coil cleaner
  • Spray bottle
  • Evaporator fin brush
  • Towel or blow dryer
  • Aluminum foil tape

As a precautionary measure, you should wear protective eye goggles and a face mask to protect your face and hands from any fumes, dirt, or debris.

When you have all of the materials listed above, you’re ready to clean the evaporator coils.

Step 2: Turn Off the AC

Before you come anywhere near any AC system, you should turn the thermostats off. You may want to switch off the circuit breaker just to be on the safe side.

It’s not necessarily dangerous to leave the AC on, but it can be inconvenient. Because you may need to temporarily move or remove components to provide a thorough cleaning, it’s safer to switch off the power.

Most thermostats have three settings: cool, off, and heat. Turn the switch to the Off position to proceed to the next step.

Step 3: Expose the Evaporator Coil

In most ACs, the evaporator coil is housed within an access panel on the furnace or air handler.

Some panels are held in place by screws, which you’ll need a screwdriver to remove. Other panels are held in place by twist levers or knobs that you can twist with your hand.

Keep one hand against the access panel as you unscrew it to keep it from falling. When you’re finished, gently pull the panel toward you and set it aside.

If the access panel has aluminum foil tape on it, peel it off and place it next to the panel if it can be reused.

At this point, you should be able to see the evaporator coils, which look like they have fins.

Step 3.1: Remove Pet Fur

If you own a pet, you may want to remove its hair from the coils before applying the cleaner. Using a compressor, blow the air in the opposite direction that it normally flows, or from the clean to the dirty side.

Step 4: Spray Cleaner on the Evaporator Coil

There are numerous coil cleaner options available on the market. Each product has different features, so before you clean the coils, choose the one that best meets your needs.

Step 4.1: Choose Coil Cleaner

The most effective and convenient evaporator coil cleaners are those that don’t require rinsing, such as the Frost King ACF19 and Nu-Calgon 4171-75 no-rinse coil cleaners. Such coil cleaners are best used when the coils haven’t been cleaned in a while.

However, if you prefer to use a milder formula, you can create a homemade solution of mild detergent, baking soda, and water. Not only is this solution effective, but it has the same foaming effect as commercial cleaners.

If you keep your AC coils clean, homemade coil cleaning solutions are a better option.

Step 4.2: Apply Cleaner to Coil

Apply a light coat of your preferred cleaner to the entire evaporator coil. It should start foaming and breaking down the dirt and debris that are reducing the AC’s efficiency.

Allow the coil cleaner to sit for 20 to 30 minutes, then reapply if the evaporator coils are still dirty.

Since it’s a no-rinse cleaner, you won’t have to rinse the coil when you’re done. Most no-rinse cleaners will foam up, turn liquid, then flow into the drain pan. Even the majority of the homemade solution will end up in the drain pan.

Keep in mind that some cleaners contain harsh chemicals, so they should only be used outside. As a result, always make sure that the cleaner you choose is suitable for indoor use.

An alternative is to use a compressor, as outlined below:

Step 4.3: Rinse the Evaporator Coil

If you use a homemade cleaner, you’ll need to rinse it off of the evaporator coil. Once the cleaner has finished foaming and done its job, you can rinse the coil in one of two ways.

Using a garden hose, you can give the coil a light spray. Just make sure that the water can drain completely.

Even better, you can fill a spray bottle with distilled water and spritz the cleaner off the coil. This method is far safer and more effective for the coil.

Distilled water is free from dissolved salts and impurities that can solidify on the coils and reduce the efficiency of the AC.

Step 5: Remove Stubborn Debris

When an evaporator coil isn’t cleaned regularly, dirt and debris can accumulate and form a stubborn layer that may require some elbow grease to remove.

If the first two rounds of cleaner don’t leave the coil spotless, you can use a gentle evaporator fin brush to remove any remaining debris. This brush is specifically designed with the appropriate bristle size and softness to clean debris off coil fins without damaging them.

Most importantly, avoid scrubbing so as not to damage the coil. You should always work gently to remove any accumulated debris.

Once you’ve removed the stubborn debris, apply a third layer of the cleaner. If it’s the non-rinse cleaner, leave it to foam and drain on its own. However, if it’s a homemade cleaner, make sure to rinse it off after 20 to 30 minutes.

Step 7: Dry the Evaporator Coil

After removing all of the dirt and debris, you should dry the evaporator coil to remove any remaining moisture.

To dry the coil, you can either towel dry it or use a blow dryer. If you use the latter, make sure it isn’t too hot.

Step 8: Replace the Access Panel

Replace the access panel on the furnace once the evaporator coil is clean and dry.

If the panel was sealed with aluminum foil tape, you should either reuse it or purchase a new one. The foil tape prevents air leaks, saving you a few bucks on your utility bill.

After cleaning the evaporator coil, you should keep the AC turned off for about an hour. If you’re cleaning the AC in the summer, you can get an early start so that you can turn it on during the hottest hours of the day.

This process should be repeated often so that you don’t end up with a messy AC:

In Conclusion

When the evaporator coils become too dirty, the AC’s performance deteriorates. That’s why it’s essential to know how to clean AC evaporator coils inside your house periodically to prevent dirt accumulation.

The wisest course of action is to learn how to clean evaporator coils without removing them. Luckily, the steps outlined above will show you exactly how to do so.

There’s no reason not to establish an evaporator coil cleaning routine and keep your AC running efficiently.

We have discussed what a condenser line is here.