How to Clean Commercial HVAC Coils

Dirty HVAC coils can significantly increase energy consumption by up to 30%, which means more money spent on utility bills and less efficiency from your system. That’s why it’s important to start a regular coil cleaning schedule right after installing new equipment. Just like visiting the dentist, cleaning might not be fun, but it's necessary—and with expert guidance, it doesn’t have to be stressful.

How to Tell If Your Coils Are Dirty

While a scheduled maintenance plan is the best way to keep your coils in good shape, there are some signs that indicate they may need cleaning:

• Check the design air pressure drop across the coil against the manufacturer’s specifications. A higher than normal pressure drop often means the coil is dirty.
• For condenser coils, high refrigerant head pressure may signal dirt buildup. For DX evaporator coils, low suction pressure and poor airflow are common signs of a dirty coil.
• Visually inspect the coils. If they look grimy or clogged, it’s time to clean them.

How Often Should You Clean Your Coils?

Under normal conditions, most commercial HVAC coils should be cleaned once a year. However, in environments with high dust, pollen, or salt air, more frequent cleaning is needed. Here are some guidelines:

• Condenser coils under extreme conditions: Clean quarterly.
• Units near saltwater (within one mile): Clean monthly.
• DX evaporator coils exposed to corrosive environments: Clean quarterly.

Step-by-Step Coil Cleaning Process

Before starting, always disconnect and lock out the electrical power to prevent accidents. Avoid getting motors or electrical components wet—this could lead to costly damage. Remove large debris and straighten any bent fins before cleaning.

Use a pressure washer with a 25–40 degree nozzle to clean the coils. Make sure the water pressure doesn't bend the delicate aluminum fins. Apply a non-acidic, alkaline-based cleaner such as Nu-Brite for condenser coils or Evap Pow’r-C for evaporator coils. These cleaners help lift dirt and grime from deep within the coil structure.

If an acidic cleaner is required, follow the instructions carefully. Any leftover residue can damage the coil. Only use a soft-bristle brush for light scrubbing, and rinse thoroughly with a pressure washer or hose afterward.

Never use harsh or toxic chemicals unless absolutely necessary. Always read and follow the manufacturer’s guidelines to avoid damaging your unit or risking personal injury.

Steam Cleaning for Indoor Units

For coils located indoors, steam cleaning is an excellent option. It effectively removes dirt without creating excessive water mess. Use low-pressure steam and keep the stream parallel to the fins to avoid damaging them.

Maintenance Makes a Big Difference

Properly maintained commercial HVAC coils can last many years. Typically, condenser coils last 10–15 years, evaporator coils 15–20 years, and water coils over 20 years. A quality replacement coil can even outlast OEM parts if made with thicker materials.

However, environmental factors—like humidity, salt air, or industrial pollutants—can shorten the life of your coils. Regular maintenance is key to keeping everything running smoothly.

What About Coated Coils?

Coated coils offer extra protection against corrosion, but they still need regular cleaning. Even though they resist rust, dirt and debris can accumulate, reducing efficiency. Clean them just like uncoated coils to ensure the coating remains effective over time.

Remember, a little routine maintenance goes a long way in keeping your HVAC system running efficiently and saving you money in the long run.

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