How to Clean Cottonwood from Your AC (DIY Guide)

Save your compressor from the "white fuzz of death" in 15 minutes.

Posted on February 9, 2026 | Location: Antelope Valley, CA

Every spring in the Antelope Valley, the cottonwood trees release their seeds. It looks like it's snowing in May. While it's annoying for your allergies, it's deadly for your air conditioner.

That white fuzz gets sucked into your outdoor unit's coils, forming a thick "blanket" that chokes off airflow. If you don't remove it, your compressor will overheat and fail.

⚠️ WARNING: Do NOT use a Pressure Washer!

The cooling fins on your AC are made of thin aluminum. A pressure washer will bend them flat, ruining your unit forever. Only use a standard garden hose.

Step-by-Step Cleaning Guide

Step 1: Turn Off the Power

Safety first. Go to your thermostat and turn it to "OFF". Then, go outside to the grey disconnect box near your unit and pull the disconnect handle, or flip the breaker in your main electrical panel.

Step 2: Inspect the Coils

Look closely at the metal fins on the sides of your outdoor unit. You'll likely see a layer of white fuzz, dirt, and maybe even some tumbleweed debris.

Step 3: The "Top-Down" Rinse

Take your garden hose with a standard spray nozzle. Set it to a "gentle shower" or "flat" setting—not "jet".

Hold the nozzle at a 45-degree angle and spray the water downwards along the fins. The goal is to wash the cottonwood down to the concrete pad. Do not spray directly horizontal initially, as you might push the dirt deeper into the coil.

Step 4: Check Your Work

Once the water runs clear and you can see the metal fins again, you're done. Let it dry for 30 minutes, then turn the power back on.

Fins Bent or Too Dirty?

If the dirt is caked deep inside the unit or the fins are bent, you need a professional chemical cleaning.

Schedule a Tune-Up