Air conditioner coils are an integral part of your HVAC system. Without the coils, you wouldn’t get the cold air from the air conditioner or the reduction in humidity from the system. Your central AC and Split AC will have two sets of coils, the evaporator coils, and the condenser coils.
This article will explain what the coils do, how they function, and the best methods to keep them clean, in good repair, and the top 6 coil cleaning products for you to use.
Problems Caused by Dirty Coils
Dirt, dust, and debris are all negative things and enemies of the AC coils. On the condenser side of things, yard waste, leaves, and even dirt will get caught in the coils and begin to build up. Once this starts happening, the refrigerant cannot cool off enough. This causes the system to slow down and work harder to keep the home at the set temperature.
Given enough build-up, the airflow will dwindle to nothing, and this can cause the condenser components to overheat. In extreme cases, the compressor, fan motor, and the capacitor can fail, resulting in costly repairs.
On the inside at the evaporator, dirty coils can spell disaster. Imagine walking into your hallway or your bathroom and stepping in a wet spot, only to look up and see water droplets on your evaporator access panel.
A dirty coil can clog the airflow, making heat transfer challenging. It can also cause the refrigerant to freeze the coils (see below for more details) and leak everywhere when it finally melts. Another thing dirty coils in the AC evaporator will do is deposit the dirt into the drain pain, eventually clogging the drain pipe.
This will not only overflow and cause a mess on your floors or counters, but also prevent the HVAC system from being able to remove the humidity in your home. Dirty coils, either inside or outside, will always cause the system to work harder than it should. This means your house won’t stay as cool as it needs to, and the system will take longer to reach temp resulting in a higher energy bill.
Checking A/C Coils
Regular inspection of your AC coils will help you know when to clean them and spot any potential problems before they become an issue. The condenser coils are the easiest to inspect. All you have to do is walk around the condenser unit and look through the air louvers to the coils.
You will be looking for dirt, leaves, sticks, yard waste, and trash. Grass clippings and blown candy wrappers are a common problem found blocking airflow and clogging up the coils.
The evaporator is a little more tricky to inspect. Depending on where your evaporator unit is located, getting to the coils can be a challenge. A-frame coils found in closet-style units will have an access panel bolted on. Once you remove the panel cover, you can use a flashlight to inspect the coils and drain pan for dirt, dust, and debris build-up.
If you have a split AC, the evaporator might be located in an attic, crawl space, or overhead hidden in the ceiling. Most installs will have the evaporator unit installed near a drain, such as a kitchen or a bathroom.
Once you open the access panel, you will see the coils. The main problem with these systems is accessing the drain pan. In most cases, you won’t be able to get a visual inspection unless you use a camera or video recorder (your phone works well, too).
If you don’t have a camera, you can reach up and place your fingers into the pan. The water level should be low, and the tray bottom shouldn’t be covered in gunk. See the section further below for cleaning methods and how-to best practices.
A/C Coil Cleaning Methods
There are several approaches to cleaning your air conditioner coils, and each one can be effective. Both the evaporator and condenser coils will have the same methodology of cleaning, just a slightly different approach.
Cleaning Condenser Coils
When cleaning the condenser coils, the first step is a visual inspection. You will want to check for vegetation growth around the pad, remove any weeds or growth that can impede the coils. On the condenser itself, you will want to remove any debris from the fins and louvers such as leaves, grass clippings, etc.
If the unit is running, you will want to turn it off to help remove the debris, as the suction created by the fan will pull things into the coils. Using a brush or broom, you can sweep and knock off the larger debris. You don’t want to brush too hard or use any force inwards towards the coils, though, as this can bend the fins.
After the larger debris items are gone, use a fin comb to straighten any bent fins and to scrape any dirt or wet debris from between the coils. Next, you will need to access the interior of the condenser. Pull the power block disconnect to remove power from the unit (some have a switch instead of a pull tab). Remove the fan shroud and lift out of the way, being careful not to pull too hard on the connected wiring.
Using a hose with a high-pressure nozzle attachment, spray the coils from the inside outward. You never want to spray into the coils from the outside as this will only push the debris into the coils deeper or cover the compressor, which can then overheat.
The coils will be clean when you can see the water coming through the fins without being distributed. Remove any debris from the floor inside the condenser unit and restore the fan shroud in place. Restore power to the unit by placing the power disconnect block back in place.
Cleaning Evaporator Coils
Cleaning your coils in the evaporator is a similar process. The first thing to do is to remove power to the evaporator. You can set the thermostat to the off position, but it is also advised to turn off the breakers that control the AC in your home’s breaker panel. Locate and open the evaporator access panel.
Once you gain access, the difficult part will be working over your head (in most cases). The coils can be found on the backside of the unit and most often will be in the most difficult place to reach as possible. Care should be taken when standing on a ladder to prevent injury to yourself.
You can use a gloved hand to remove the bulk of the debris build-up, which will be wet and, most likely, the texture of mud. Using a fin comb, scrape the coils from the top down, being careful not to get snagged, and rip the fins. This will also help straighten any fins that may have become bent.
You will need to use a chemical coil cleaner. Most will foam and set in to remove dirt and build-up gunk. Follow the instructions for application and set time. It is advised to wear eye protection when spraying the coil cleaner.
While the cleaner works, take the time to clean out the drip tray where the condensation collects. You can use a scraper to dig up the muddy debris from the bottom of the pan. Before you begin to scrape, though, you need to locate the drain line.
The drain line will be a PVC elbow that comes out at the bottom or side of the low end of the drain pan. You will want to scrape away from this area. If you scrape towards it, you run the risk of pushing debris into the drain line, causing a clog.
Rinsing the Evaporator Coils is Crucial
Once the drip tray is cleaned, use water to rinse off the coils. You do not want to use a high-pressure spray because you will be spraying into the coils. Like the condenser coils mentioned above, using force to spray from outside in can cause deeper clogs.
Rinse the coils cleaner and debris it has collected into the drip tray and down the drain line. Flush the drain line by running hot water through the drip tray for about 10 minutes.
If your evaporator is located above your bathtub, the drain will connect to the tub drain system. Before flushing, you should remove the drain stopper mount and weight. This will cause the drain line to empty into the tub. You will be able to see when the drain is clean because the rinse water will be free of debris.
Replace all of the items you removed in the tub drain and the evaporator access panel and restore power to the AC. Check that there are no leaks, strange noises and that the air blows hard and cold from the vents.
Heavy Duty Coil Cleaning
If you notice the coil cleaner or fin combs are not penetrating the build-up, you may need to call in a professional HVAC specialist. They will have the tools, means, and ability to perform a deep clean on your coils.
This may also be a benefit to you if you have a difficult to access the evaporator unit or for any other reason cannot do the job yourself. The best place to find a reputable HVAC cleaning specialist is through Angie’s List or Thumbtack.
According to Home Advisor, you should expect to pay between $100 and $400 for professional cleaning of both condenser and evaporator coils.
DIY vs Professional Cleaning Costs
If you are looking to save money, the DIY option is always available. While personal safety is paramount, the job can be done for just the cost of the cleaners and tools. If you already have most of the tools, you can save even more.
A professional will need to come to inspect the coils before offering a quote, which can take time. You should receive at least three quotes before picking a professional. If you are short on time, the DIY option is better for you.
As a DIY project, the coil cleaners, fin combs, brushes, screwdrivers, and other materials you need will cost you between $40 and $150 total. Of course, this doesn’t account for your time and effort, as well as clean up.
Based on the cost of the products alone, it may be beneficial to you to have a professional come in and clean the coils for you. You may spend more than $150, but with the time you free up and the effort you save, it might be worth it to you.
Features of Great A/C Coil Cleaners
When looking for coils cleaners, there are a few things you need to be on the lookout for that make a great AC coil cleaner. There are hundreds of brands (most you have never heard of) and off-market products that claim to clean your coils thoroughly.
However, due to the nature of the job, you will want a cleaner that is proven and has the right ingredients to get the job done right the first time. Let’s take a look at what to look for in your coil cleaner.
Alkaline-based cleaners have a low odor, which is excellent for people with odor sensitivities. They are also known for their overall cleaning abilities and are found in most cleaning products. Alkaline-based coil cleaners are adept at loosening grease, smoke residue, and other sticky messes. This makes them ideal for coils, which can become caked in all of these items.
You will want a coil cleaner that is easy to use. Some spray cans require you to be a certain distance that may not be possible with your HVAC set up. If you get too close, the spray could be too powerful and go through the coils instead of creating the foam on the coils.
Other cleaners will require diluted mixtures, brush applications, or other steps that you may not want to deal with. Finding the right coil cleaner will involve the least amount of steps as possible.
Because the chemicals involved can be corrosive to metal, skin, hair, and the mucous membranes, it is crucial that you only get cleaners that are USDA Authorized when possible. If the Federal Government hasn’t inspected it, you can’t be sure what is actually inside.
Multiple cleaning applications from the same product is always a good idea. Some coil cleaners are designed to clean more than just coils, making the purchase a smarter option because you can do more than put the can in under the sink waiting until next year. Versatile cleaners will have many applications and uses.
No Harmful Additives
If you have allergies, sensitivities, pets, or other concerns, you should seek out cleaners that don’t use harsh chemicals or include harmful additives. Some consumers felt if the cleaner can’t be applied directly to the skin, it shouldn’t be used in the home.
There is a range of coil cleaners that fit this category and do a decent job at removing gunk from the AC coils.
6 Best Coil Cleaners Reviewed
We have reviewed the six best coil cleaners for you and present them to you here. Find your next coil cleaner below.
1. Nu-Brite – Best Alkaline Based AC Coil Cleaner
Nu-Calgon 4291-08 offers you Nu-Brite, a 1-gallon jug of coil cleaning power. This formula is non-acidic and alkaline-based.
Designed for condenser coils, you should not use this solution for evaporator coils. For interior application, see the Nu-Calgon evaporator cleaner below.
The solution should be applied via a spray bottle for precise application and little waste.
It will foam up when it contacts contaminates, so you will see it working. After spraying, it should be left alone for ten to 15 minutes before being rinsed off. The Nu-Brite formula is also USDA authorized, so it is safe for use in all areas.
2. Frost King – Best Foaming AC Coil Cleaner
Frost King ACF19 is a foaming spray from a can designed to clean condenser coils, evaporator coils, fins, and drain pans.
It uses an odor neutralizer to block foul odors and leaves behind a lemon scent. The foaming action loosens build-up and brings embedded debris to the surface for rinsing away.
The chemicals are non-corrosive and won’t hurt the fins, coils, or drain trays. You shouldn’t spray directly on painted surfaces, though, as it can eat through some paints and clear coats. They can also come with a fin brush cap, which you can use to scrub stubborn areas before rinsing.
When the cleaner has done its job, rinse thoroughly so as not to leave any cleaner behind.
3. Nu-Calgon Evaporator Cleaner – Best No Rinse AC Coil Cleaner Spray
Nu-Calgon is arguably the most thorough coil cleaner on the market. It can be used for condenser coils but is designed for evaporator coils and indoor uses.
The foam spray will loosen and lift grease, grime, dirt, and other materials and doesn’t need to be rinsed clean.
Over time, the cleaner will dissipate and run down the coils into the drip tray, taking the dirt and debris with it. If you plan to use this on the evaporator, it is advised you thoroughly clean the drain tray, pan, and line prior to spraying. This will prevent clogs from the removed debris.
The non-toxic spray is safe for all metals, plastics, and painted surfaces. Overspray should be wiped up quickly, though, as it can stain.
4. Web – Best Condenser Coil Cleaner
Web makes a condenser coil cleaner that is safer for the environment and your pets. The biodegradable formula is designed to be sprayed on and rinsed away.
You won’t have to scrub the coils unless there is a major gunk build-up, and you can rinse away from the outside of the condenser without having to access the interior of your condenser.
When rinsing, you should use nominal pressure from a garden hose and not a spray nozzle; otherwise, this will push the solution and debris back into the coils. It is also ill-advised to use indoors on your evaporator coils as there isn’t a degreasing solution involved. Surface contamination of the evaporator coils would be cleaned, but the grime and grease will remain.
5. Midwest Hearth – Best Coil Cleaning Whisk Brush
The whisk brush from Midwest Hearth is a durable and easy to handle brush. It is designed to help clean off the condenser and evaporator coils, find and air louvers.
You can also use the brush to clean your AC vents, air intake vent louvers, and other hard to clean areas.
It is not advised to use on evaporator coils that haven’t been washed previously as the grease will cause the dirt to stick to the bristles. If this happens, you need to rinse and soak the brush on hot water with a mild detergent and hand wash the bristles to get them clean.
On the condenser coils, the brush can be used at any time and will get between the fins to remove debris stuck deep in the coils.
6. Ivation – Best Evaporator And Condenser Coil Washer
The portable sprayer has a built-in water tank and rolls easily on castor wheels. You can take this sprayer anywhere as it is run on batteries instead of electricity.
This makes it ideal for spraying out condenser coils since you don’t need to worry about running an extension cord around the house.
The 130 pounds per square inch of spray pressure won’t harm fins or coils and make cleaning your AC coils quick and simple. You can also use a mild detergent or a homemade coil cleaning solution with vinegar to have a more powerful cleaning solution besides just water.
Types of A/C Coils
Unless you are using a window AC, you will have two sets of coils. Evaporator coils will be found inside, with the evaporator unit, while the condensing coils are found outside around the large condenser unit. Let’s take a look at how they function.
The evaporator coils conduct the heat transfer to turn the warm air inside your home into cool air blown from your vents. These coils have the cold, high-pressure refrigerant running through them at cold temperatures.
The blower motor brings air in through the induction vent and pulls it through the coils. As the air passes over cold coils, the heat from the air is transferred to the refrigerant inside, making the air cold and the refrigerant hot. The cold air is then blown through exhaust vents around your home while the heated refrigerant is pushed outside to the condenser.
By the time the vapor has reached the condenser, it has low pressure and high temperature. The condensing unit sucks the refrigerant through the coils where the condensing fan pulls air from the outside through the coils. The opposite heat transfer happens outside. The colder air absorbs the heat from the low-pressure gas, which cools it off.
Once it has cooled off, the hot air is blown out the top of the condenser by the condenser fan, and the refrigerant is passed into the compressor. It returns to high pressure, low-temperature liquid, and is sent back to the evaporator where the process repeats.
Frozen Air Conditioner Coils
Frozen air conditioner coils are a common issue and can be caused by a few different culprits. Let’s take a look at the various causes of frozen coils.
Clogged Air Filter
Blocked airflow is the leading cause of frozen coils. This can be due to dirty coils as described above, but it can also be as simple as an air filter past the change date.
A dirty air filter prevents air from freely flowing through the system and can also allow contaminants in which start clogging the evaporator coils. If you notice the system running longer, working harder, or your set temperature not being reached, the first step is to change your air filter.
The second most common problem leading to frozen coils is low refrigerant levels. Since the refrigerant flow system is a closed-loop, you should never have to refill or top-off your refrigerant. If you have an inspection on the system done and there is a low level of refrigerant, you have a leak somewhere.
Usually, the leak will happen at the weakest spot of your system. The refrigerant fill valves have a valve core, similar to the valve core in your car tires. The rubber gaskets on these cores can wear out, allowing little amounts of refrigerant to escape every time the system comes on. Over the course of a few weeks, you will have low enough refrigerant levels to cause ice to form.
When this happens, the first place you will find ice is on the copper tubing leading to the condenser unit. The ice will eventually cover the compressor and then move to the condenser coils when it gets bad. Spotting ice early is key, which is where your regular inspections will come into play.
Clogged Interior Coils
Your system will also freeze if the refrigerant cannot get through due to clogged coils on the inside. Most of the time, this is only caused by physical damage to the coils, but if there is also a leak, contaminants can enter the coils and get caught in the bends.
If you notice ice build-up and the above two situations do not apply, you will need to have a pressure test performed. This is the only way to find out if the problem is clogged interior coils.
Importance of Regular A/C Maintenance
Regular AC maintenance is a crucial part of your home’s efficiency. A well-running, clean air conditioner will help lower your monthly energy bill as well as provide cool air when you need it.
Cleaning the condenser coils should be done on an as-needed basis. During the spring and summer months, debris can easily clog the coil fins. Grass clippings, leaves, trash, and debris will all blow around and be caught by the condenser unit.
Weekly visual inspections will tell you when it is time to clean the coils off. At a minimum, cleaning should be performed at the start of the AC season before you turn the air conditioner on for the first time. From there, every six to eight weeks is a preferred interval.
The Evaporator coils should be cleaned at the start of every season. As long as you replace the air filter regularly, dust and dirt build-up shouldn’t be an issue while the machine is running. Build up will occur during the offseason when you are running the heater or nothing at all. Beyond this annual cleaning, there shouldn’t be a need for any other cleaning times.
People Also Ask (FAQ)
Let’s answer some of the frequently asked questions about the air conditioner coils and keeping them cleaned.
Can I clean A/C coils with vinegar?
Yes, a diluted mix of half white vinegar and half water in a spray bottle will help to clean the AC coils. The mixture will remove dust and light debris build-up but will not penetrate through layers of gunk often found in the evaporator coils. As a regular, monthly cleaning solution, though, it works reasonably well.
How can I make a homemade coil cleaner solution?
There are several homemade solutions that you can make that have some limited effect on cleaning air conditioner coils. Aside from the vinegar mix mentioned above, you can add in a tablespoon of baking soda to the vinegar and water for a more foaming cleaner.
You also have the option to use a light detergent, such as your dishwashing liquid. This is designed to cut through grease and grime. Mixing a small amount to a spray bottle of water will create a grease-fighting solution you can use directly on your coils.
When should I replace evaporator coils?
The idea of changing the evaporator coils is a tricky situation. In most cases, it is advised that you do not replace the coils, but instead replace the entire evaporator.
By the time the evaporator coils become so degraded they need to be changed, the rest of the air conditioner will also be at an age where replacement is recommended. Putting new coils in an old system is ill-advised and can end up costing you more money in the long run.
Where is the best place to buy ac coil cleaners?
If you decide to go with a commercial product, you can pick them up at any home improvement store. However, for the best deals and possible discounts, finding your coil cleaner on Amazon is a better idea. Amazon will have the cleaner in stock and save the hassle of ensuring you are paying a fair price.
How much does ac coil replacement & repair cost from a professional?
According to Home Advisor, the average replacement and repair costs for an air conditioner coil is between $650 and $1,200. This will depend on the hourly labor rate of the installer, ease of access, and any other factors that come up with the removal and installation process.
Keeping your air conditioner coils clean is an important step in maintaining your AC efficiency. Dirty coils can prevent proper airflow, overheat the system, and cause the air conditioner to fail. Condenser coils can be cleaned with a garden hose and some elbow grease. Evaporator coils need AC coil cleaners and some tools.
Access is important, too, as well as your personal safety. Always remove power to the condenser and evaporator before beginning work. Cleaning the AC coils can be a simple DIY job or may require a professional. Either way, you go, you will prolong the life of your air conditioner and keep your monthly energy bill low.
Last Updated on July 14, 2022
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