How to Clean Commercial HVAC Coils

Dirty HVAC coils can increase energy usage by up to 30%, which means more costs and less efficiency. That’s why it's important to establish a regular coil-cleaning routine—especially after installing new equipment. Just like visiting the dentist, cleaning might not be fun, but it's necessary. With expert guidance, it doesn’t have to be a hassle either.

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 a few signs that indicate they need attention:

• Check the design air pressure drop across the coil compared to the specifications. A higher than normal pressure drop may mean the coil is dirty.
• For condenser coils, high refrigerant head pressure is a red flag. For DX evaporator coils, low suction pressure and poor airflow could signal buildup.
• Visually inspect the coils. If they look grimy or clogged, it’s time for a clean.

How Often Should Coils Be Cleaned?

Under normal conditions, condenser and DX evaporator coils should be cleaned once a year. However, if you’re in an area with high cooling demand or heavy dust, you may need to clean them more frequently.

• Condenser coils under extreme conditions: Clean quarterly.
• Units near salt water: 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 accidents. Avoid getting motors or electrical components wet, as this can cause damage. Remove large debris first, then straighten any bent fins.

Use a pressure washer with a 25–40 degree nozzle to clean the coils without bending the delicate aluminum fins. Apply a non-acidic, alkaline-based cleaner like Nu-Brite for condensers or Evap Pow’r-C for evaporators. These cleaners help lift dirt from deep within the coil structure.

If you must use an acidic cleaner, follow the instructions carefully. Residue left behind can corrode the coil and reduce its lifespan. Only use a soft-bristled brush if scrubbing is needed, and rinse thoroughly with a power washer or hose.

Use Steam to Minimize Mess

For interior coils, steam cleaning is an effective and mess-free option. It removes dirt without excessive water, making it ideal for sensitive areas. Keep the steam at low pressure and parallel to the fins to avoid damaging them.

Maintenance Matters

Properly maintained commercial 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, especially if made with thicker materials.

However, environmental factors—like proximity to salt water, humidity, or industrial areas—can significantly impact coil longevity. Always consider these when planning your maintenance schedule.

What If My Coil Is Coated?

Coated coils resist corrosion better, but they still need regular cleaning. Dirt and debris can build up just like on uncoated coils, so maintaining them the same way is crucial. This ensures the coating remains effective and protects the coil for years to come.

Remember, a little care goes a long way. Regular cleaning and maintenance can save you money, improve efficiency, and extend the life of your HVAC system.

Have a question or need a coil quote? Contact us anytime!