What is Evaporator Coil Cleaning?

HVAC professionals run across common problems every summer, and you have probably experienced most of them with your own system. Have you ever turned on your AC to find that barely any air is coming from the vents? Or maybe your AC isn’t cooling your home or business down at all and you notice that water is dripping from your ceiling or around the furnace. These are a couple of the symptoms that could be the result of a dirty coil. Of course, we recommend hiring a professional to do an official diagnosis before concluding a dirty coil, but coil cleaning is a common repair.

What is the evaporator coil?

Before we can get into coil cleaning, let’s understand what the evaporator coil is and the part it plays in your system operation. In a split central HVAC system, the evaporator coil is the “indoor coil” that actually gets cold when you are using your air conditioning. This coil is built like a radiator, but contains refrigerant where the system’s heat transfer occurs from the air inside your house. If you have a split HVAC system and your furnace is in the garage or in a closet, the evaporator coil is the unit that is set on top of the furnace. If your furnace is in your attic, the evaporator coil is the unit set in front of the furnace.

How is it cleaned?

For proper operation, your system needs the correct amount of airflow to move across the evaporator coil to be cooled. Since the evaporator coil is a metal unit and contains refrigerant, condensation accumulates on the coil as it cools air. If unfiltered air enters the area where the coil is, any dust, dander, or debris particles will stick to the condensation.

If the issue is not addressed, thick layers of gunk will cake on the coil, obstructing airflow and forcing your coil to work harder to cool the air. When you have a coil cleaning done, a technician must remove the coil, scrape and clean all the filth using a special chemical solvent, and then return the coil to its original spot.

How does the evaporator coil get dirty?

Your evaporator coil gets dirty from unfiltered debris getting to the coil and sticking to it. Over time, it accumulates and hinders air flow while also making it harder for the coil to cool the air through all the debris stuck to it. So, the real problem is dirty air getting to your coil. Here are a few ways that dirty air can get to your coil and cause problems:

Running your system with an improperly-sized filter or no filter at all

If you are using your system without a filter or filter that is too small, you are sure to run into multiple problems. In Southern California, we use our air conditioners a lot and if there is no filter or there are gaps that allow air particles to bypass to the coil, your coil will get dirty very quickly. If your system has a disposable filter, make sure to replace it with the correct sized filter needed. You can either measure the dimensions, look at the system manual, or look at the labeling on the old filter if it was the proper size.

Leaks in your ducts

If you have any damaged ducts where air can leak from your system, there is a good chance that unfiltered air will get sucked in through those leaks or through the return air duct. Dust and dirt from your attic or underneath your house can get into your air circulation and eventually make its way to the evaporator coil where it will stick to the condensation.

Lack of maintenance

We’ve said it several times, and we will say it again: system maintenance is crucial to your system’s performance and life span. Neglected filters will become plugged and thus useless. If you have multiple pets and find yourself changing your filter all the time, you may want to look into air purification options. Neglected ducts can be damaged by rodents or outside factors and cause leakage. Your system should be professionally maintained at least once per year in addition to general maintenance by the owner.

Improper installation

Sometimes people hire unlicensed HVAC workers to install their new system because they promise a cheap and fast installation. The problem with this is that untrained professionals often don’t have the correct equipment or training sealing off return air cavities or testing air leakage in your ducts. Improper installation can leave gaps and unsealed crevices where dirty air can contaminate your system and stick to you coil.

How do you know if your system is installed properly?

In the state of California, city permits and inspections are legally mandatory for HVAC installations. Special duct testing and efficiency commissioning are required in order for the installation to pass inspection, even if you did not have the ducts replaced. If your contractor is not pulling city permits for your installation, there is a greater chance that improper sealing or system leakage will be missed, leading to pricey repairs in the future.

How much does coil cleaning cost?

Coil cleaning is an unwanted repair that is both expensive and preventable. If your coil has gotten so dirty that it has affected system performance, you need to have a professional cleaning done. This repair is labor-intensive and varies in work time and price depending on how dirty the coil is or where the coil is located. Some coils are in areas that are not accessible or hard to reach, so removing the coil can be problematic, adding to labor costs. Cleanings can take anywhere from two to five hours and can cost up to $300 to $600.

Remember that dirty coils are preventable with proper installation and care for your system. Make sure that your system is:

• Properly installed
• Maintained regularly with proper air filter change-outs, duct repairs if needed and correct system operation
• Professionally maintained at least once a year (we recommend biannual maintenance: once in Spring and once in Fall)

If you take care of your system, you will avoid most if not all these pricey repairs. If you have any questions about coil cleaning or our system maintenance programs, contact us.