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How to Clean Evaporator Coil in an Air Conditioner


An evaporator coil is an important component of any air conditioner. It works by taking the warm, moist air from inside your house and passing it over cold refrigerant-filled tubes, allowing heat to be drawn out of the warm air. The now-cooled air is then pushed back into your home through a fan. This process is responsible for cooling your air.

Regularly cleaning the coil is integral to the AC’s long-term health. It helps keep your air conditioner running efficiently and reduces energy costs.

What is the Difference Between an Evaporator Coil and a Condenser Coil?

The evaporator and condenser coils are important parts of the air conditioning unit. Both components work together to keep your house cool, but each has its own distinct purpose and function vital to the cooling process.

In a split-system unit, there is an indoor unit which is typically the coil and the outdoor unit which is the air conditioning unit. The major differences between evaporator and condenser coils are in their location and purpose.

Located inside the home, the evaporator coil is located on the air intake side of the fan coil. It is also sometimes referred to as the cooling coil. It’s responsible for removing the heat from indoor air so that the blower fan can return cool air to the home. On the other hand, located in the outdoor unit is the condenser coil. This is responsible for releasing the captured heat outside. 

What are the Symptoms of a Dirty Evaporator Coil?

When an AC coil becomes dirty, it can cause several issues. If left unchecked, the dust, dirt, and debris that accumulate on the surface of the coil can reduce its efficiency and make your air conditioner work harder to cool your home. This in turn can lead to a variety of problems. 

The AC helps remove unwanted and uncomfortable humidity from your home as a natural part of its process and if you have dirty coils, it can bring higher humidity and less overall comfort inside your house. The unit may also have decreased cooling efficiency due to dirt buildup on the surface.

Furthermore, a blocked coil often causes the compressor to run at higher temperatures. As the compressor increases in temperature, it can place stress on the entire system. The compressor is one of the highest cost-replacement items in the AC system and protecting this can help you avoid expensive bills.

Here are some common signs of a dirty evaporator coil:

Ineffective Cooling

If you notice that your air conditioner isn’t as cool as it used to be, this could be a sign of a dirty coil. You might notice that your living space is warm or that it takes quite a long time to cool down. The air may also not reach the temperature you set on the thermostat.

Longer Operation of the Air Conditioner

If you find that your air conditioning unit runs for longer cycles without achieving the same amount of cooling inside the house, then a dirty coil might be the culprit. When the air it produces isn’t as cold as desired, the air conditioning unit has to work harder to bring the temperature down to the desired level. 

Unusually High Electricity Bills

If your air conditioning unit runs longer than usual in order to meet the cooling demand, then you might notice that your electricity bills are higher than usual. 

Does Cleaning AC Evaporator Coils Really Help?

Absolutely! Due to the dirty coils, your house will become less comfortable and you might even acquire rising utility bills. Getting the HVAC coils cleaned is a cost-effective way to care for your unit.

Cleaning the coils of your air conditioner will help the unit perform and do its job properly. It’s important to have clean coils so that your air conditioner will remain in top shape and last longer. Cleaning the coil can also help you avoid a costly repair bill or keep you from buying an entirely new air conditioning unit when you least expect it.

How Do You Clean an Air Conditioner Evaporator?

Dirt and debris stuck in the coil can reduce airflow which is so important to the performance of your system. To remove the dirt and keep your system from malfunctioning, cleaning the coil regularly and doing a maintenance check are effective ways to care for your system.

What Can I Use to Clean Air Conditioner Coil?

The indoor coil is typically mounted to your furnace and has its own cabinet or is housed inside a fan coil or air handler unit. On the other hand, the condenser coils can be found in the exterior unit, usually wrapped around the interior components and acting as the side walls.

The coils are delicate parts of the air conditioner, especially the fins which help the heat transfer. It’s important to ensure that they do not get damaged during the clean-up. You can clean the air conditioning unit yourself with a cleaner or hire a professional air conditioning unit cleaning service to do it for you. 

The most reliable way to ensure that all parts of your air conditioner are running smoothly is to hire a professional air conditioner cleaning service. They can test the system as well prior to the cooling season to ensure that it is running at its peak. However, if you insist on cleaning your air conditioner and the coils on your own, you can use things such as compressed air, household detergent, or commercial cleaners. 

The combination of compressed air, a shop vac, and a heavy-duty coil-cleaning chemical is best to use for the condenser coil located in the outdoor part of the unit. When cleaning the exterior AC coil using compressed air, blow air through the AC coils in opposite the direction that air flows through the AC coil during normal use. This will result in pushing air through the cleaner side back through the dirtier side. Be sure to blow air straight through the fins and not at an angle.

Air conditioner unit coils can also be cleaned with a solution of mild household detergent and water. Using a low-pressure air conditioner sprayer, the detergent and water mix are applied to the coils and are either allowed to drain naturally or rinsed lightly with a garden hose.

Make sure that you don’t use a pressure washer to remove the debris as you’re more likely to damage thin metal fins. Damaged fins can restrict airflow and reduce heat transfer capabilities. Additionally, ensure that you will not use a highly acidic cleaner. Acidic cleaners can also damage the copper and alloy metals used in the coil. They can also cause corrosion, which will shorten the life of the coil and the system. 

Air conditioning coil cleaning can also be done using commercial cleaners. There are several types of air conditioning cleaner solutions, including foaming cleaners for the outdoor coil. You can clear the surface debris with a special fin brush. As for the indoor part of the coil, a special brush can be used.

How Do You Clean an Evaporator Coil Without Removing It?

Each AC model is a little different but the location of HVAC coils is standard and so, it will be pretty easy to access them. One of the best ways to clean the coil of the system without removing it is to use a compressed air canister.

First, turn off the air conditioner and remove it from the plug. Next, remove the access panel to expose the evaporator coil of the system. Make sure to go through your system manual to make sure that you are taking apart the correct parts. 

Once the access panel is off, remove the screws or fasteners. Then, use a compressed air canister and blow air into the coil to loosen the dirt. If there is stubborn dirt, you may need to put the canister’s nozzle closer to the bottom. Once done, you can cover the coil again and secure the access panel in its place.

How Often Should Evaporator Coils Be Cleaned?

The most obvious answer to this question is, of course, the AC coils should be cleaned when they’re dirty. How quickly the coil gets dirty depends on a lot of factors: how often the system is used, how often the filter is changed, the amount of debris or dust both inside and outside, the number of people living in a house, and more. 

As a rule of thumb, it’s best to have a professional perform a maintenance check on your system at least once a year. Most professionals will have services such as air conditioner coil cleaning, and air conditioning system filter change, and they can even test the system to ensure everything is running smoothly.

Is It Worth Replacing an Evaporator Coil?

You may be thinking that the AC coils can be replaced if ever they get damaged and while that is true, replacing the system coils may cost you more in the long run. For one, your new coils will no longer match the HVAC condenser or the refrigerant type. Mismatched coils can be the cause of more problems and you may acquire higher energy bills and more frequent repairs than before.

Additionally, due to the replacement of coils, your AC may work again but it would be less efficient than before. This can cost you in the long run and you may even end up needing to replace your entire AC unit instead. Regular maintenance to remove dirt and debris is more practical and cost-effective. 

How Long Does an AC Coil Last?

An HVAC coil can last around ten years or more with proper maintenance. It will eventually wear and may need repair or replacement. When it breaks, it may be best to replace the whole AC unit. 

Final Thoughts

Regularly cleaning and maintaining your coil will ensure that your house stays comfortable and efficient all year round. Additionally, if you notice any signs of dirt or debris buildup, it is best to connect with an expert and have the coil checked and cleaned by them as soon as possible.

Some professionals even offer inspections along with a guarantee against breakdown. With the right care and maintenance, your air conditioner coil can last for many years to come.

JP Reyes

JP has been in the aircon industry for almost as long as he has been alive. As a child JP would help his tatay fix aircon units at their junk shop in Cavite. After graduating UP in the early 2000's, JP then started his own Aircon servicing business and within 5 years had 10 shops in 8 different cities. Fast forward to today and JP brings all his experience and expertise online to give readers trustworthy advice and reviews about Air-conditioning buying, servicing, cleaning and repair in the Philippines.

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