HVAC Training Shop is reader-supported. As an Amazon Associate, I earn from qualifying purchases.
Walking into a cool home is one of the greatest comforts I enjoy on a hot summer day. However, there is some effort I need to put in to ensure that my home stays cool and comfortable. One of these things is routine HVAC maintenance on my AC’s coils.
Dirty coils won’t exchange heat properly and will reduce the efficiency of an air conditioner. Simply put– dirty coils in an AC system will waste energy. If my coils were always dirty, I’d end up spending way more money on my electric bill!
One thing that I do every year is wash my coils using an AC coil cleaner. AC coil cleaners are specially formulated to remove the gunk and grime from AC coils and maintain the lifespan of an air conditioner.
In this article, I’ll review the best AC coil cleaners and discuss the pros and cons of each of them.
List of the best air conditioner coil cleaners
Nu-Calgon Evap Foam No Rinse Coil Cleaner
Best Overall Coil Cleaner
- Foams up to dislodge debris
Frost King Foam Coil Cleaner
Best Budget Coil Cleaner
- Includes a brush on the cap
Strongest Coil Cleaner
- Only for use on outdoor coils
WEB WCOIL19 Coil Cleaner
Best Biodegradable Coil Cleaner
- Biodegradable and non-fuming
ComStar Coil Safe Cleaner
Safest Cleaner for Coils
- USDA authorized and safe to use on both indoor and outdoor coils
Best AC coil cleaner reviews
This spray-on coil cleaner helps remove grime build-up from your dehumidifier coils. Better yet, it doesn't require a rinse after you use it.
The Nu-Calgon Evap Foam No Rinse Evaporator Coil Cleaner is a spray cleaner that foams up to remove dirt, grease, oil, and other residues.
This foaming coil cleaner is detergent-based and is ideal for cleaning evaporator coils since it has a fresh lemon scent. However, it can be used on condenser coils as well.
After applying this coil cleaner, the foaming action works to dislodge debris inside the coil. Rinsing the coil after using this cleaner is not required, but I recommend spraying down the coil with water to ensure that all debris is clear from the coil.
The Frost King Air Conditioner Coil Foam Cleaner is a detergent-based foaming coil cleaner. It is ready to use and comes in a spray can for easy application.
I would recommend that you first use a brush on your coil to dislodge debris before applying this foam cleaner. This will help the foaming action of this cleaner to efficiently remove dirt and grime from a clogged coil.
If you are using this on an evaporator coil, then rinsing the coil after cleaning it is optional. After turning the AC back on, the condensation on the evaporator coil should be enough to wash away the residue and foam from the coil.
After you’re done, this cleaner has a fresh lemon scent that smells great and lets you know that your coils are clean.
Nu-Brite is an alkaline coil cleaner suitable for deep cleaning stubborn coils. It is caustic, so it should only be used on outdoor coils.
The Nu-Calgon Nu-Brite Condenser Coil Cleaner is an alkaline-based coil cleaner that is suitable for deep cleaning.
First of all, it should be noted that this cleaner is NOT for use on indoor coils. Only use it outdoors.
Because it is caustic, be sure to use protective equipment such as gloves, goggles, and protective clothing when using this product.
This cleaner needs to be diluted with water in a 4:1 water:cleaner ratio. You will also need a sprayer to apply this product onto your condenser coil. After applying this cleaner, it foams up to deep clean and removes all sorts of dirt, grime, and residues from your coil.
One thing that should be noted is that you should not use this cleaner on coils that have paint or powder coating on them because it may damage the coating. Only use this cleaner on bare metal condenser coils.
The WEB WCOIL19 Coil Cleaner is biodegradable and non-fuming. This makes it ideal for use on any type of AC coils, even indoor evaporator coils.
Like other spray cleaners, it is a foaming detergent-based coil cleaner that does not require rinsing if used on an evaporator coil (although rinsing with water after using it will certainly help).
One thing that I love about this coil cleaner is that it can spray no matter which way you turn the can. This helps to ensure that you are able to spray the cleaner in tight spots where you might need to orient the can upside down.
This solvent-based cleaner is best for removing grime and smoke residue. Dilute it with water in a separate sprayer. However, it does emit some fumes so be sure to use it in a ventilated area.
The ComStar Coil Safe Evaporator and Condenser Coil Cleaner is a solvent-based coil cleaner. It is USDA authorized and safe to use on both indoor and outdoor coils.
One thing that I like about this coil cleaner is that it is self-rinsing and does not require you to rinse the coil with water after using it. However, the cleaner does give off an odor, so be sure that you use it in a well-ventilated area.
When using this coil cleaner, be sure to dilute it with 1 to 5 parts water for every 1 part coil cleaner.
To apply this cleaner, you will need to use a sprayer to ensure that you can apply it to all parts of the dirty coil. You don’t need to rinse the coil with water after using this cleaner. But for an excessively dirty coil, you will want to rinse it with water afterward.
How to clean your AC coils
Part of your routine HVAC maintenance should include checking and cleaning your AC coils as needed. AC coils are prone to collecting dirt and grime, and regular cleaning may be needed, particularly for condenser coils that are exposed to the outside.
Below are some general steps that you can take to clean your AC coils:
Step 1: Power off AC unit
The first step is to turn off power to your AC unit at the disconnect. Turning off power at the disconnect ensures that the AC unit is completely de-energized and won’t electrocute you when cleaning the coils.
It is also wise to wait for a few minutes after turning off the power to allow stored electricity to dissipate from the AC unit’s internal electrical components.
Step 2: Gain access to AC coil
The second step is to gain access to the AC unit’s coil so you can clean it. Depending on the make and model of your AC unit, you may need to remove screws and panels to expose the AC coil.
Step 3: Clean AC coil
The third step is to clean the AC coil. There are a few different ways that you can clean AC coils:
- Blow out dust from the coil using compressed air
- Suck out dust from the coil with a vacuum cleaner
- Spray the coil down with a water hose
- Use an AC Coil cleaning solution
Using compressed air or a vacuum cleaner to clean your AC coils is the most straightforward approach and is recommended for cleaning off mild dust buildup.
If you are shooting compressed air into your coils, be sure that you are shooting the dust OUT of the coil, not IN the coil — you don’t want the dust going deeper into the coil!
For dirtier coils, sucking the dust out may not be enough, and you will need to spray the coil down with a water hose to clean off dirt and grime.
For the dirtiest coils, an AC coil cleaning solution is recommended to clean off stubborn built-up grime. Using a coil cleaning brush is recommended to scrape off residue.
This fin and coil cleaning brush is soft enough to slide into coils—but it’s also stiff enough to scrape off grime when used with a coil cleaner.
In any case, be sure that you prepare the surrounding area for whatever cleaning method you choose.
For example, if you are going to be spraying down your AC coil with water, be sure that the area around the AC unit is okay with getting a little wet.
If you are cleaning a coil that is indoors, you should consider setting up a plastic tarp underneath the AC unit to catch the liquid runoff.
How to Clean an Evaporator Coil
If you are going to be cleaning an evaporator coil on an indoor unit, using a water hose or an AC coil cleaning solution might not be an option. Evaporator coil cleaning should be done with caution because evaporators are usually exposed to the indoor environment.
One way to clean an evaporator coil is to use a foaming coil cleaner.
Some of the best AC coil cleaner sprays do not require rinsing, so you can just spray the cleaner on and then run the AC unit. The condensation from the evaporator coil will rinse the foam off after you are done cleaning it.
Step 4: Reassemble AC unit
After you are done cleaning the coil on your AC unit, the next step is to put everything back together.
If you used water or a cleaning solution to clean your AC coil, be sure that the coil is clean, dry, and free of dust, dirt, and grime. A few last-minute touches may be required, such as wiping away loose material with a cloth or a brush.
Step 5: Power on AC unit
Once you put the paneling and screws back on your AC unit, the final step is to power back on your AC unit and make sure that it runs.
If you cleaned the evaporator coil you might find that the air coming out of the unit smells different than it used to. The smell is caused by one of two things: the fragrance from the coil cleaner, or the air picking up smells from the metal coil instead of the dust that once layered it.
Types of AC coils
In any kind of air conditioning system, there are two types of coils: The Evaporator Coil and Condenser Coil. Both types of coils look the same, but their purpose and location within the HVAC system are different.
The evaporator coil is sometimes referred to as the cooling coil. The responsibility of the evaporator coil is to cool indoor air by removing heat from it.
The evaporator coil is located on the air intake of the fan and cools indoor air as the air passes through the coil.
The condenser coil is found on the outdoor unit. The purpose of the condenser coil is to release heat to the outside of the building.
On window AC units, the condenser coil is located on the back of the window AC.
Both types of AC coils are usually made of a copper tube that is surrounded by aluminum fins for improved heat transfer.
When the coils get dirty, their heat transfer capabilities are diminished, and their performance is reduced. Simply put, dirty coils make your AC work harder and will make your electricity bill go up!
Worse yet, if your AC has dirty coils, the AC won’t perform as well and may have a hard time cooling and dehumidifying your home.
Types of AC coil cleaners
The main characteristic that you need to keep in mind when purchasing an AC coil cleaner is what type it is.
There are many different ways that coil cleaners work. Some are made out of soap and simply dissolve dirt and residue, while others will strip away the top layer of metal on the coil (for a very very powerful clean!)
Acidic coil cleaners
Acidic coil cleaners are powerful cleaners and will definitely get your coils clean. However, they have the potential to damage your air conditioner coils if misused.
Acidic cleaners will remove the top layer of metal on your AC coil. This means that acidic cleaners have the potential to cause your coils to leak if they aren’t used properly. Worse yet, acidic coil cleaners produce toxic vapors, which are extremely dangerous if inhaled.
Alkaline coil clenaers
Alkaline cleaners will clean your AC coil much better than just using water. Additionally, alkaline cleaners do not readily strip away the top layer of metal on the AC coil, so there is less potential for damaging your AC coil.
While they are not as dangerous as acidic cleaners, alkaline cleaners are still caustic and should be handled with care.
Solvent-based coil cleaners
Solvent-based coil cleaners clean AC coils by dissolving residues. They are effective at removing grease and smoke residue but are ineffective at removing heavy buildup and corrosion.
Solvent-based cleaners work quickly, and you won’t need to rinse the coil off after using it. The drawbacks of solvent cleaners are that they are usually flammable and produce strong odors when using them.
Detergent-based coil cleaners
Detergent-based cleaners are soapy cleaners that typically include foaming agents and surfactants to help with the cleaning process. Many detergent-based cleaners come in a spray can and are easy to use.
These types of cleaners usually require some amount of rinsing with water after using them. One advantage of some of the newer detergent-based cleaners on the market today is that they are environmentally friendly.
AC coil cleaner features
There are a few different features between air conditioner coil cleaners. When looking for the best AC coil cleaner, it is important to keep the following characteristics in mind:
Ease of use
Having a cleaner that is easy to set up and apply is your best bet.
After all, why should you use a coil cleaner that is hard to use when the whole point of using a coil cleaner is to make your job easier?
Some air conditioner coil cleaners come in a spray can that makes it very easy to apply.
Other coil cleaners come in big bottles. For these types of cleaners, you need to dilute the solution with water. Next, put the mixture in a pump sprayer and spray down your coils with the mixture.
Some air conditioner coil cleaners will foam up after they are sprayed onto an AC coil.
While some people think that the coil cleaner should always foam, this is not always true. If a coil cleaner foams too much, the foam will prevent the cleaning solution from contacting all surfaces of the coil.
The excessive foaming action will also push residue and debris toward the center of the coil, making it harder to remove.
The truth is that some foam is good, but you don’t want too much. A little bit of foam is a good thing to harness the cleaning potential of your coil cleaner. Mild foam is your best bet for cleaning a coil without overwhelming it.
As discussed above, some cleaners are safer to use than others.
While some cleaners are caustic and dangerous to touch, other types of cleaners are mild and environmentally friendly. Depending on your situation, you will need to decide what type of coil cleaner you want to use and if it is safe to use in the situation that you will be using it in.
In particular, acidic and alkaline-based coil cleaners are dangerous to handle. Some solvent-based cleaners emit fumes that should not be inhaled.
Generally, detergent-based cleaners are the safest type of coil cleaner to use.
Maintaining your air conditioner coils is one of the most essential parts of HVAC maintenance. Though it can seem complicated at first, there are many tools, techniques, and products out there that simplify this task.
One of the greatest benefits of routine AC coil cleaning is improved energy efficiency — clean AC coils almost always mean a lower electricity bill.
Using an AC coil cleaner is one of the easiest and quickest ways to clean your air conditioner coils. Now that you know what the best AC coil cleaners are, you can make an informed decision about what product is right for the job.
Need more info?
If you’re going to be cleaning your AC coils, then you might as well straighten out your fins while you’re at it. Bent fins can reduce the efficiency of your AC, costing you more money to use it.
Check out our reviews on the best AC fin combs for coil repair to find out more.