Does your mini split smell like “dirty socks” when you turn it on? Have you seen small black flakes shooting out of the vents?

That is mold. Because mini splits are dark, damp, and cool, they are the perfect breeding ground for mold and bacteria. Breathing this air can cause allergies and respiratory issues.

Professional HVAC companies charge $250 to $400 for a deep cleaning. In this guide, I will show you how to do a “Deep Clean” yourself in less than an hour, using simple tools.

Step 1: The Easy Part (Filters) 🕸️

You should do this every 2 weeks.

Lift the front panel.
Pull out the mesh filters.
Wash them in the sink with warm water.
Let them dry completely before putting them back.

💡 Pro Tip: If the filters are caked with grease (kitchen unit), use a little dish soap.

Step 2: The “Hidden” Enemy (The Blower Wheel) ⚙️

This is where 90% of the mold hides, and most people miss it. The “Blower Wheel” is the long cylindrical fan that spins inside. Look closely with a flashlight. If you see fuzzy black stuff on the blades, you are breathing mold.

To clean it without making a mess, you need a “Cleaning Bib”.

What is a Bib? It’s a plastic bag with a drain hose that straps around the AC unit to catch all the dirty water so it doesn’t ruin your wall.

cleaning mini split air conditioner unit

Step 3: The Coils (The Fins) ❄️

The metal fins behind the filters also get clogged.

Spray: Use a “No-Rinse Coil Cleaner” (available on Amazon).
Wait: Let the foam sit for 10-15 minutes. It will eat away the grime.
Rinse: Spray gently with water (using a pump sprayer). The water will flow into the drain pan and go outside.

⚠️ Warning: Do not use a high-pressure washer (like a Karcher) on the fins. You will bend the delicate aluminum metal and ruin the airflow. Use a hand pump sprayer only.

Step 4: The Drain Pan & Line 💧

If your unit smells like standing water, the drain pan might have “slime” in it.

The Fix: Pour a cup of distilled white vinegar (or bleach mixed with water) slowly over the coils. It will run down into the pan and kill the bacteria in the drain line.