You Don't Have To Make The Same Mistakes

I always took my home's heating and cooling system for granted. That is until I found myself battling one of the hottest days in years and my air conditioner simply refused to turn on. After contacting my local HVAC contractor, I learned that my cooling coils had frozen over from a lack of maintenance. He did get my AC back up and running that day, but he also helped me to look at my heating and cooling system in a whole new light. I have spent a lot of time over the last few years learning more about how to properly maintain my HVAC system and ultimately lower my energy costs. Today, I would like to share this knowledge with you so that I can help you to avoid some of the costly mistakes I have made in the past.

Algae Growing On Your A/C Coils? Here's How To Take Care Of It


You expect to see algae growing in ponds, on rocks and in places where moisture is in abundance. But you don't expect to see algae growing on your air conditioner's indoor evaporator coil. As it turns out, the environment underneath your A/C's plenum is just perfect for algae spores to flourish.

The last thing you need is for algae buildup to bring your A/C's performance to a standstill, especially as you gear up to tackle the summer heat. The following is a comprehensive guide for dealing with algae growth.

How Algae Growth Damages Your A/C

Your air conditioning system's evaporator coil is just one of several components that are constantly kept in the dark. Not only is it located in a space that receives little to no natural sunlight, but it's also kept moist due to the condensation that drips from the coil as it extracts and transfers heat.

Algae, mold and mildew all happen to thrive in these dark and damp places. Once it eagerly makes itself home, it takes over and makes a mess of your A/C system:

  • Algae growth on the evaporator coils prevents them from transferring latent heat, causing the coils to freeze over and the unit to cease working until they're unthawed and the coils themselves cleaned.
  • Algae clogs up condensate drain pipes, trapping ever-growing amounts of condensate in the pan until it finally overflows.
  • An algae outbreak also creates a musty odor that emanates throughout the entire HVAC system.

Getting rid of algae growth is an important step when it comes to checking and repairing your home's cooling system before summer arrives.

Removing Algae Growth from Condensate Drains and Pans

The first thing you want to do before tackling algae head on is to make sure the condensate pan isn't full of water. A good wet/dry shop vacuum comes in handy for getting rid of standing water, although it's also possible to carefully remove the pan itself and dump its contents down the drain. And speaking of standing water, it's a good sign that your condensate drain pipe's clogged with algae and other debris.

To clear up clogs caused by algae growth, you can connect your shop vacuum's hose to the mouth of the drain pipe and use its suction to dislodge the clog. Particularly stubborn clogs may need the help of a plumber's snake to get moving. Nevertheless, you'll want to get the condensate drain unplugged before dealing with the evaporator coil.

To keep algae from making a grand comeback, you might want to try the following preventative steps:

  • Mix a half-cup of bleach with a half-cup of water and pour the mixture down the drain shortly after removing the clog. This destroys most of the algae remnants that are still in the drain pipe.
  • Use zinc or copper pan strips or tablets to keep algae growth at bay. Both copper and zinc are elements commonly used to control organism growth in underwater environments.
  • Consider investing in an ultraviolet (UV) lamp. Exposure to UV rays disrupts the algae's reproductive cycle, making these lamps very effective for controlling algae growth.

Removing Algae Growth from Evaporator Coils

Cleaning the evaporator coils is a crucial step towards eliminating algae growth. The best way to do this on your own is by using a special no-rinse foaming coil cleaner. The cleaner's foaming action helps dislodge the algae mass, while the "no-rinse" portion allows the residue to harmlessly drip off of the coil, leaving behind a cleaner and blockage-free coil.

Using the no-rinse cleaner also spares you the frustration of physically cleaning the evaporator coil. Bending the delicate fins lining the evaporator coil can be just as bad, if not worse than the algae growth itself – both actions block airflow from getting where it's needed most.

Of course, you can always have a seasoned air conditioning professional clean your evaporator coil for you. It's a good choice for those who are worried about the potential damage a DIY cleaning could cause.


9 March 2015