Symptoms
- Reduced cooling performance
- AC running longer than usual to reach the set temperature
- Visible dirt, grass clippings, leaves, or dust caked on the outdoor unit's fins
Likely causes
- CommonNormal outdoor debris accumulation over a seasonGrass clippings, dust, pollen, and leaves naturally build up on the coil fins over time.
- CommonLandscaping or lawn mowing blowing debris directly onto the unitMowing near the unit without care can pack clippings into the fins.
- PossibleVegetation growing too close, restricting airflowBushes or tall grass within a couple feet of the unit can restrict the airflow it needs.
What to do
- Turn off power to the outdoor unit at the disconnect before cleaning.
- Remove any large debris (leaves, sticks) from the top and sides of the unit by hand.
- Gently rinse the fins from the inside out with a garden hose on a low-pressure setting, working from top to bottom.
- Avoid using a pressure washer, which can bend the delicate fins and damage the coil.
- Trim back any vegetation to keep at least 2 feet of clearance around the unit on all sides.
- Plan to clean the coil once or twice per cooling season, more often if there's heavy pollen, dust, or nearby lawn mowing.
Tools and parts
- Garden hose
- Soft brush
When to call a pro
An HVAC technician can perform a deeper coil cleaning during a routine maintenance visit if buildup is heavy or hard to reach.
Safety
Use caution
Always cut power at the disconnect before cleaning near the unit's fan or electrical components.