The Fundamentals of Treating White Slime (White Algae)

White slime is gross and is difficult to look at. Every time I see the goo, I fear for my life thinking that one of Ridley Scott’s aliens is hanging above me. I have to be brave though, I have to save my HVAC system.

What is this Slime?

Let’s take a trip back to biology class for a quick minute. White slime is a build-up of microbial cells and water. Inside the gooey substance is a colony of microscopic single-celled organisms.

Slime in Your HVAC System

With the inside of your heating and cooling system being dark and damp, it’s the ideal growing condition for this invasive slime. Given the warmth that the summer months bring, white slime is most common from May through August. Dust particles pass through the filter, slime collects, mimicking a food-like substance that allows the colony to keep growing.
This is a list of places where slime can be found in your HVAC system includes:
  • Evaporator pans
  • Drain lines
  • Drain pans
  • Condensate pumps
  • Condensate lines
These are the most common areas a technician will find the slime. You can anticipate more slime in any area that is dark and damp. If the slime is present, it can adapt to any living situation.

The Issue with White Slime

Slime build-up can cause an array of issues for your facility, including inefficiencies in your HVAC, property damage, and health hazards.
When the slime is blocking lines or building up in pans, it can cause damage to your HVAC system. This will cause discomfort among your facility’s occupants. But don’t worry, that’ll be the least of your worries when examining your system. Blockage in your HVAC’s condensate lines and pans can lead to restrictive flow and cause significant issues in drainage and airflow. If left untreated, a bad build-up could result in your facility’s HVAC systems condensate system flooding, creating water spots or water damage.
When the unit is unable to drain, you’ll see property damage as a result. Overflowing condensate can cause mold and mildew in dry areas. Plus, if an overflow of drainage reaches the carpet or drywall, you’ll likely have expensive cosmetic damage or mold remediation.
If you leave the white slime untreated within your HVAC, occupants will experience poor air quality as the air flows throughout the system. Additionally, if the sludge leads to mold and mildew, serious health concerns could arise.
[Seasons may come and go, but maintaining your HVAC’s annual maintenance remains the same. Learn how annual maintenance can keep your system up and running in How HVAC Maintenance Saves You Time and Money.]

Eliminate the White Slime

The most common misconception with white slime is that you can wipe up the growths. Even with antibacterial cleaners, we can almost guarantee that you’ll see slime in the same area within the next year.
Follow these steps to reduce the chances of white slime:
  1. Remove the air filter. The bacteria from the slime can collect here, and might be doing your system harm.
  2. Use a strong suction vacuum to remove all dust, debris, and slime.
  3. Rinse the lines and pans with a 50/50 bleach and water solution. Cleaning these will help to kill any remaining cells.
  4. Finally, replace your air filter.
Are you still seeing an issue? Give an expert a call. They’ll be able to offer further advice, or worst-case scenario, they’ll remedy your problem in person.
Don’t have the stomach to do it yourself? Rasmussen Mechanical Services will remove the invasive white slime from your HVAC system. We will implement a solution to reduce the risk growth in the future. Give us a call at 1-800-237-3121 or drop us a line to talk with our team.
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