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Why Clean AC Coils? The Definitive Answer

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Last Updated on August 30, 2017


If you’ve got air conditioning equipment that you rely on, chances are you probably understand the importance of regular maintenance. But the trouble is, not all preventative maintenance agreements include coil cleaning. If your service vendor has been recommending this procedure, you may be wondering why you need to clean AC coils.

Here’s a quick explanation followed by more information for those of you who want the details.

Why clean AC coils? The short answer

Dirt & grime on AC coils makes it harder for your equipment to transfer heat. That means it has to run longer and work harder to do it’s job, using more energy and causing parts to wear and break down. Dirty coils also get corroded which leads to refrigerant leaks.

Need to know more? Keep reading to learn more about why the AC coils need to be clean and what happens when you neglect cleaning the AC coils for too long.

For those of you in New York City, we don’t need to tell you about the air quality issues. That’s a big contributor to problems with AC coils. Get the facts about the special requirements for coil cleaning in the city: A Guide to Air Conditioner Coil Cleaning: Why, How, and How Often.

Coil Cleaning Could Save You Big $$$. Download the Free Guide

What do the AC coils do?

Your AC coils are some of the most important parts of the air conditioning system. There are two types of coils: EVAPORATOR coils (part of the indoor unit) that absorb the heat and humidity from the air in your space; and CONDENSER coils (typically located outside) that expel that heat outside of your building.

When the outside of the coils collect a layer of dirt and contaminants, the transfer of heat (into the evaporator coil and out of the condenser coil) becomes much less efficient. That causes a number of problems that you’ll start to notice as the problem gets worse (detailed below).

If you ignore the symptoms for too long, your system can overheat and ultimately fail completely. That’s why you should clean your AC coils without delay.

The consequences of not cleaning AC coils

Not convinced yet about why to clean AC coils? Here’s what happens when dirt and debris build up on your air conditioner’s evaporator and condenser coils.

  • Your system runs longer without cooling as effectively. When the evaporator coil is dirty, it can’t absorb as much heat. Therefore, you may notice that your system keeps running almost constantly while having trouble reaching set temperature. (Learn more: Your AC Running Constantly is Trying To Tell You Something.)
  • Your system uses more energy and drives up your electric bill. the more it runs, the more your utility expenses go up! Have you noticed a spike lately? It may be a good reason why you should clean the AC coils.
  • Parts wear more quickly. Excess heat, pressure, and increased run times cause parts to wear out sooner. You’ll have more problems with fans, belts and other components.
  • Refrigerant leaks can occur. Grimy AC coils can develop corrosion on the outside, especially the outdoor condenser coils that are exposed to smog, exhaust fumes and other outdoor pollutants. Over time, corrosion causes cracks and holes in the coils, which allows refrigerant to leak. As the refrigerant charge is reduced, your system’s ability to cool is gradually reduced. (Learn more: AC Troubleshooting: Refrigerant Leak.)

If your system was installed prior to 2010 and uses the old refrigerant R22 (also known as Freon), you have an even bigger problem on your hands. That’s because Freon is being phased out and therefore repair costs are skyrocketing. (If you’re in this situation, read this to find out what to do.)

  • Your system fails before its time. Without getting too technical, when the AC coils are dirty, the refrigerant flowing through the coils can’t change from liquid to gas (and back) as it’s supposed to. That causes increased strain on the compressor, which is the heart of your air conditioning system. When the compressor goes, it’s an expensive fix at best, you might be need a complete replacement.

Obviously that’s going to cost you… and we don’t only mean the cost of buying and installing a new air conditioning system. What about the cost of going without AC for weeks or longer, while you sort through estimates and wait for an install date? If you’re a business owner, consider the cost in lost productivity from overheated employees, and even the cost of lost business.

Don’t let things get to this point! Now that you know WHY to clean AC coils, take care of the problem right away. Next, find out how often you’ll need to do it in the future to protect your system.

How often you need to clean AC coils

How much dirt is too much? Why to clean the AC coils is only half of the question. The rest is how often to do it.

Ideally, your vendor will clean your AC coils as part of your regular preventative maintenance contract, which you need at least once or twice per year. The frequency depends on a few factors:

The age and condition of your equipment. If your equipment has not been well maintained, it may have corrosion that collects more debris.

Your usage. If yours is a commercial system that runs 24/7 all year long, you’ll need to clean your AC coils more frequently.

Location. Is it close to street level where pollution levels are higher? Is there construction or demolition going on nearby that’s spewing debris into the air? Is the unit exposed to exhaust from nearby kitchens or factories? If so, you’ll need to have the coils cleaned more often.

Trust the professionals: this is not a DIY task

You may be tempted to clean the AC coils yourself to reduce expenses. That’s not the best idea, because those small fins you see on the outside of the coils are very sensitive. If you use the wrong types of cleaners or the wrong technique, they can easily become damaged. The small cost you pay to have it done correctly can save you a bundle in repair expenses.

Hopefully that explains everything you need to know about cleaning the AC coils. But if you do have more questions, feel free to reach out to us at Arista anytime!