HVAC Evaporator Coil Cleaning: All You Need To Know Before Cleaning

An HVAC system is essential in keeping your home cool and comfortable, especially during the hottest months of the year. However, a thick layer of dust can settle on your HVAC unit’s evaporator coil, leading to reduced efficiency or even costly repairs.

Compressed air or water spray is one of the best ways to remove light dirt and dust particles on your HVAC evaporator coils. Some select chemicals can also be used to remove stubborn dirt. With proper HVAC system maintenance, you can cut energy bills by up to 30%.

In this article, I’ll discuss how to clean an HVAC evaporator, how often you should clean the coil, and some essential tips to keep in mind while doing so.

How To Clean an Evaporator Coil: Steps, Tips, Key Considerations?

The evaporator coil is essential for the efficient functioning of an HVAC system. It absorbs heat as air passes over it. If you have temperature zones set in your home, the evaporator plays a vital role in ensuring that these areas have the desired air temperature.

The evaporator coil is behind a protective panel, making most people assume it is safe and free from contamination. However, this is not the case. The air that flows into the system contains dust particles that easily get stuck on the surface of the coils. When an evaporator coil retains moisture from the dehumidification process, dust and dirt particles can settle onto it.

Dirt buildup within the evaporator is a common cause of an HVAC system’s malfunction. When dirt builds up inside the evaporator, it restricts airflow and prevents air from entering the heat exchanger. This prevents proper heat transfer and can result in too little heat being absorbed from the air. The buildup of dirt also affects other components of the heating system, such as condensers, blowers, and fans which all impact your HVAC system’s performance.

HVAC systems must be clear of dirt and clogs for an effective cooling and heat transfer process. Dirty evaporator coils not only lead to eventual system failure but could also cause your HVAC parts to work harder to maintain the desired temperature. All these translate to a higher electrical bill.

Read: How To Fix Air Conditioner Leaking Water Inside?

Steps To Clean an Evaporator Coil

A poorly performing HVAC could indicate a dirty evaporator coil that needs to be cleaned. Cleaning your evaporator coil regularly is the best way to keep your system working efficiently. 

Follow these steps to maintain the cleanliness of your HVAC system’s evaporator coil:

  1. Turn off the HVAC system and remove the section of the outer panel. Cleaning while your HVAC system is running poses the risk of an electrical shock, so don’t forget to shut down the fan and cut the power to the whole unit.
  2. Blow out large particles using compressed air. Compressed air takes out tiny particles that don’t require much effort to expel. However, this may not be enough if your equipment has not been cleaned in a while.
  3. Brush the coil. Using a soft brush, brush the coil from the top, working your way down. Brushing removes dirt that is otherwise difficult to remove using compressed air. You can apply more pressure when removing stubborn dirt. Be cautious not to exert too much force, as this could damage the unit. 
  4. Spray the coil cleaner.  Deep cleaning of the evaporator coil requires more than just a brush or spray. You can use heavy-duty cleaning chemicals and a steam cleaner or pressure washer to remove stubborn dust buildup. Let the cleaner sit for a few minutes and allow it to soak and loosen the dirt for easy removal.
  5. Wipe the coil with a soft cloth. Avoid leaving any wet detergent on the coils. Find a clean, soft cloth and wipe the coils carefully to remove any remaining liquids.
  6. Allow the coil to dry for a few moments. Once it’s dry, return the panel cover to its place and turn the unit back on.

Read: 3 Reasons Why Air Handler Is Leaking Water

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What To Use To Clean an Evaporator Coil?

Spraying with clean water is one of the most cost-effective and efficient ways to clean an evaporator coil. Not only is cleaning with water a fast process, but it also requires minimal effort, making it the go-to solution for many people looking to maintain their HVAC system

However, in some cases, spraying water alone isn’t enough to properly remove all dirt on your evaporator coil. In these cases, you can use chemical cleaners instead. These cleaning solutions are specially designed to break down more stubborn build-up on coils, helping them run more efficiently over time. These cleaning agents can often be combined with water for even better results.

If you choose to clean your evaporator coil using a commercial product, note that not all chemical cleaners can be used to clean the evaporator coils. Acid-based cleaners, for instance, are harmful and could damage the coil’s metal surface. Chemicals like chlorine-based cleaners can corrode aluminum when used as a cleaning agent.

Aside from cleaning agents, you may need a screwdriver to loosen up any tight parts that need to be assessed. Don’t forget your gloves and safety glasses.

Key Things To Consider When Cleaning an Evaporator Coil

Cleaning an evaporator oil is a delicate process that requires caution. It is advisable to clean the evaporator coil with the right materials and do it regularly to keep your unit in tip-top shape.

Here are some key things to consider when cleaning an evaporator coil:

  • Safety comes first. Wear safety glasses when cleaning your evaporator coil to protect your eyes from the dust particles blown out of the coils. Turn off the power to the unit and only attempt to clean it when the unit is disconnected.
  • Avoid using tools that will damage your equipment. Steer clear of corrosive cleaners that can damage copper and aluminum coils. 
  • Don’t use hard plastic brushes or sharp-edged tools. These could pierce the coil and cause damage.

Read: Why Is AC Producing So Much Condensation?

How Often Should You Clean an Evaporator Coil?

You should clean your evaporator coil at least once or twice a year. While air filters reduce the dust and dirt that goes into your HVAC system, the dirt still builds up on the coils over time.

Several factors will determine how frequently you should clean your evaporator coil. These include:

  • Location. If your house is near factories or construction sites, dust from these sites will find its way into your space and eventually into your HVAC unit’s coils. This will require you to clean your system more often.
  • Usage. How often you use your system and the size of the space, it is cooling can also determine how much maintenance is required. 
  • Age. An old HVAC unit is more likely to require more frequent cleaning than a new system. That’s because old equipment has degraded efficiency and may not be powerful enough to overcome dirt accumulation.  

Even if your air conditioning is working well, professionals recommend that you have it cleaned, checked, and serviced regularly. This is the only way to ensure that it will serve you for years.

Read: Why AC Freezing Up? -Troubleshooting Guide


Regular maintenance is key to ensuring the efficient operation of the evaporator coil and your HVAC unit. We recommend that you seek professional help if you’re unsure how to clean your evaporator coils.