How to Clean Commercial HVAC Coils

Dirty coils can significantly increase energy consumption—up to 30% in some cases. That’s why it’s crucial to implement a regular coil-cleaning schedule, especially after installing new equipment. Just like visiting the dentist, coil cleaning may not be something you look forward to, but it’s necessary for long-term performance and savings.

How Do I Know If My Coils Are Dirty?

While a scheduled maintenance plan is the best approach, there are a few signs that indicate dirty coils:

• Check the design air pressure drop across the coil compared to the manufacturer's specifications. A higher than normal pressure drop often means the coil is dirty.
• For condenser coils, high refrigerant head pressure may be a sign of buildup. For evaporator coils, low suction pressure and poor airflow could indicate dirt accumulation.
• Visually inspect the coils. If they look dirty or clogged, it’s time for a cleaning.

How Often Should Coils Be Cleaned?

Under normal conditions, commercial HVAC coils should be cleaned at least once a year. However, certain environments require more frequent attention:

• Condenser coils under extreme conditions: Clean quarterly.
• Units near saltwater (within one mile): Clean monthly.
• Evaporator coils in corrosive environments: Clean quarterly.

Step-by-Step Coil Cleaning Process

Before starting, always disconnect and lock out the power to the unit to avoid accidental startup. Avoid saturating motors or electrical components. Remove large debris and straighten any bent fins before cleaning.

Use a pressure washer with a 25–40 degree nozzle to gently clean the coils. Avoid bending the delicate aluminum fins. Use non-acidic, alkaline-based cleaners like Nu-Brite for condensers and Evap Pow’r-C for evaporators. These cleaners help lift dirt from deep within the coil structure.

If an acidic cleaner is required, follow the instructions carefully. Residue left behind can damage the coil. Only use soft-bristled brushes for gentle scrubbing, and rinse thoroughly with a hose or pressure washer.

Steam Cleaning: A Cleaner Alternative

For interior coils, steam cleaning is an effective way to remove grime without leaving excess water behind. Keep the steam pressure low and direct it parallel to the fins to avoid damaging them.

Maintenance Matters

Properly maintained HVAC coils can last many years. Condenser coils typically last 10–15 years, evaporator coils 15–20 years, and water coils over 20 years. Quality replacement coils can even outlast OEM parts, thanks to improved materials and construction.

However, environmental factors like humidity, pollution, and proximity to saltwater can shorten coil life. Always consider these elements when planning maintenance schedules.

What If My Coil Is Coated?

Coated coils offer protection against corrosion, but they still need regular cleaning. The coating itself can become clogged if not maintained properly. Cleaning coated coils the same way as uncoated ones ensures their longevity and effectiveness.

Regular maintenance isn’t just about saving money—it’s about ensuring your system runs efficiently and safely. Don’t neglect your coils; they’re a critical part of your HVAC system.

Have questions or need a coil quote? Reach out to us anytime—we’re here to help.