Skip to Content

Here's How a Dirty Furnace Coil Can Affect Your HVAC System


Free airflow is elemental and essential to HVAC function and efficiency. Hopefully, you are staying on top of basic maintenance such as changing your furnace filter to help keep energy bills low. Though, there is one component you may not have considered for disrupting HVAC operation. Have you checked to see if you have a dirty furnace coil this season?

Effects of a Dirty Furnace Coil

When airflow is impeded at any stage of home heating and cooling, you are going to experience a loss of comfort, higher energy bills, and greater HVAC system wear. Some of the common obstructions to airflow are a clogged air filter, leaky ducts, obstructed registers and closed doors. Though, a dirty furnace coil is just as common if not more.

The reason the coil gets so dirty is that dirt and debris stick to it easily — especially during the cooling months when condensate forms on it. Additionally, the blower in the typical furnace and A/C configuration pulls airflow directly through the coil's air passages in cooling and heating modes. So, whether you use a furnace or heat pump for heating, the coil affects airflow.

HVAC Maintenance

Your HVAC system should be serviced by a professional in the fall and spring seasons. Following are the basic steps to clean your furnace coil:

  • The door to the plenum and furnace coil are removed.
  • Compressed air is used to remove loose debris.
  • An industrial-strength coil cleaner is applied to the outside and under-side of the coil.
  • The condensate pan is inspected for mold and other contaminants.
  • The coil is wiped or rinsed clean and chemically treated to prevent mold development, as is the condensate pan.

Preventing a Dirty Coil

In addition to fall and spring HVAC maintenance, one of the best and simplest ways to keep your furnace coil clean is by changing your air filter as needed. Check each month during peak season.

If a dirty furnace coil is plaguing your furnace, contact Valley Heating, Cooling, Electrical. Visit our website for in-depth information on most HVAC topics, or just give us a call at (408) 868-5500.

Our goal is to help educate our customers in the South Bay Peninsula and Santa Cruz areas of California about energy and home comfort issues (specific to HVAC systems).

Share To: