How-to guides
How to clean a dirty AC coil with foam: a 4-step SOP
A safe routine for split AC coils: power off and open up, remove loose dust, apply Aerosure AC Foam Cleaner, then rinse or drain gently and restore power.
A dirty coil makes an AC run longer for the same cooling. Our article on why dirty coils cost power covers the research. This page is the routine itself, the way we train technicians to use Aerosure AC Foam Cleaner.
Step 1: Power off and expose the coil
Switch off the AC and isolate the electrical supply. Open the access panel to expose the evaporator or condenser coil. Protect nearby electrical components from moisture, and wear gloves and eye protection.
Step 2: Remove loose dirt
Use a soft brush or a vacuum to remove loose dust and debris. Always brush in the direction of the fins, so you do not bend them.
Step 3: Apply AC Foam Cleaner
Shake the can well. Spray Aerosure AC Foam Cleaner evenly across the coil, holding the nozzle at the distance given on the product label. Let the foam penetrate and work on the dirt and grime between the fins. Do not spray directly onto electrical components.
Step 4: Rinse or drain, then restore
Follow the product's rinse or no-rinse instructions. If rinsing is needed, use gentle, low-pressure water, never a high-pressure washer. Let the excess water drain away completely. Refit the access panel and restore power only when the area is safe and dry.
Common mistakes
- Skipping the power isolation because the job is quick.
- Spraying foam into the control board or motor.
- Using a pressure washer, which bends fins and pushes water into places it should not go.
- Switching on before the unit is dry.
See the steps as a 3D walkthrough on the Aerosure technician page.
Quick answers
Can I clean an AC coil without a pressure washer?
Yes. A foaming coil cleaner such as Aerosure AC Foam Cleaner penetrates between the fins and loosens dirt. If the label calls for a rinse, use gentle low-pressure water, never a pressure washer.
Is it safe to spray foam cleaner on AC electrical parts?
No. Switch off and isolate power, protect electrical components from moisture and keep the foam off them.
When can I switch the AC back on after cleaning?
Only after excess water has drained, the panel is refitted and the area is safe and dry.