Dirty Rooftop Unit Coils Are Costing You — Here's What You Need to Know

If the evaporator coils on your rooftop package unit are dirty, your HVAC system is likely working harder, costing more, and delivering less. Left unchecked, dirty coils can lead to reduced cooling, costly repairs, and even equipment failure.

Here's a close-up of a plugged rooftop unit evaporator coil.

7 Common Problems Caused by Dirty Evaporator Coils

Reduced Cooling Efficiency

Dirt acts like insulation. It blocks heat transfer, so your system can’t effectively absorb indoor heat, reducing overall performance.

Higher Energy Bills

The harder your system works, the longer it runs. And the longer it runs, the more you pay in electricity.

Coil Freezing

When refrigerant gets too cold due to poor heat transfer, moisture freezes on the coils. This further restricts airflow, worsening cooling performance.

Compressor Damage

Frozen or overworked coils put stress on the compressor, a critical and expensive component. Failure can result in significant downtime and extensive repairs.

Reduced Airflow

Dirt buildup restricts airflow, causing uneven cooling, poor humidity control, and temperature fluctuations, or "hot/cold zones," in your building.

Poor Indoor Air Quality

Dust, mold, and biological growth on coils can lead to musty odors and even respiratory health concerns for building occupants.

Short Cycling

When your unit frequently turns on and off, it’s a sign of stress. Short cycling accelerates wear and reduces your system’s lifespan.

What You Can Do

To protect your system and optimize performance:

• Schedule regular coil inspections and cleanings — ideally every 6 to 12 months.

• If coils are heavily soiled, professional deep cleaning is recommended using commercial-grade coil cleaners and rinse methods.

• Upgrade filters or increase filter change frequency to prevent future buildup.

Need Expert Help?

Owens Companies offers professional coil inspection and cleaning services for commercial rooftop units. Our technicians can quickly assess the condition of your coil, recommend solutions, and restore your system to peak efficiency.

Ready for a service estimate?

Contact us today to schedule a rooftop unit inspection or one-time coil cleaning.