How to Clean Commercial HVAC Coils

Dirty HVAC coils can significantly increase energy consumption by up to 30%, which is why it’s crucial to implement a regular cleaning schedule—especially after installing new equipment. Just like a visit to the dentist, coil cleaning may not be something you look forward to, but it's an essential part of maintaining your system. With the right tools and guidance, it doesn’t have to be too bad.

How Do I Know If My Coils Are Dirty?

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

• Check the air pressure drop across the coil compared to the design specifications. A higher than normal pressure drop usually means the coil is dirty.
• For condenser coils, high refrigerant head pressure is a sign of buildup. For DX evaporator coils, low suction pressure and poor airflow may indicate a problem.
• Visually inspect the coil. If it looks dirty, it probably is.

How Often Should Coils Be Cleaned?

Under normal conditions, a DX evaporator or condenser coil should be cleaned once a year. However, in areas with high dust, humidity, or pollution, more frequent cleaning is necessary. Coils with high fin density tend to collect dirt faster and require more regular maintenance.

Condenser coils under extreme conditions: Clean quarterly

Units near saltwater (within one mile): Clean monthly

DX evaporator coils in corrosive environments: Clean quarterly

How to Clean a Coil

Before starting, always disconnect and lock out the electrical power to avoid any risk of the unit turning on. Avoid saturating motors or electrical components, as this could lead to damage.

Remove large debris and straighten any bent fins before cleaning. Use a pressure washer with a 25–40 degree nozzle to avoid damaging the delicate aluminum fins. Apply a non-acidic, alkaline-based cleaner like Nu-Brite for condenser coils or Evap Pow’r-C for evaporator coils. These cleaners help lift dirt from deep within the coil.

If you must use an acidic cleaner, follow the manufacturer’s instructions carefully. Any leftover residue can harm the coil. If scrubbing is needed, only use a soft-bristled brush. After cleaning, rinse thoroughly with a power washer or hose.

Never ignore the manufacturer’s guidelines when using chemical cleaners. Improper use can cause serious damage to your system or even personal injury. Always wear protective gear and ensure proper ventilation.

Use Steam to Minimize Mess

For interior coils, steam cleaning is an effective and less messy alternative. It helps loosen dirt without over-saturating sensitive components. Keep the steam pressure low and apply it parallel to the fins to avoid bending them.

A Little Maintenance Goes a Long Way

Properly maintained commercial HVAC coils can last many years. Condenser coils typically last 10–15 years, DX evaporator coils 15–20 years, and water coils over 20 years. A quality replacement coil can often match or exceed the lifespan of an OEM part, especially if it uses thicker materials.

However, environmental factors like location, humidity, and exposure to chemicals can affect the coil’s longevity. That’s why regular inspections and cleaning are so important.

What If My Coil Is Coated?

Coated coils resist corrosion from contaminants, but they still need regular cleaning. Even coated coils can become clogged, so maintenance should be done just as frequently as with uncoated ones. Proper care ensures the coating remains effective over time.

Regular maintenance isn’t just about keeping your system running—it’s about protecting your investment. If you have questions or need a quote, feel free to reach out anytime.