The first point that is very important to remember about Mold and Air Conditioning is that: “Your A/C Unit is the perfect environment to grow Mold and Algae.” Microbial growth is very common in your drain pan. It is a wet and humid area.
I can check my unit every month and will find a slime mold growing in the drain pan. Some people will put an anti-microbial tablet in the pan to help keep the levels down but it is only partially affective. Some microbial growth is unaffected by this process. Remember, Mold and Algae love to live in your A/C System because of the amount of water always present in the drain pan.
I know, you ask; ” How Can I Stop This?” The answer is: “Turning off your A/C off is the only solution.” In reality, this is impossible due to where some people live. Hot and Humid climates such as Florida make this impossible, especially in the Summer months.
Some A/C Contractors will recommend you get a UV Light, but remember, they are only partially successful. Plus, there are some individuals who are allergic to the low levels of ozone being generated by the UV Lights. I have multiple clients who cannot use UV Lights because of this problem. Another downside which we discovered recently, they tend to cause your plastic drain pans to deteriorate and crack. This is what I call a Catch-22 of one solution causing another problem.
The best solution is a high quality pleated filter to help prevent a build up of organic material in the first place. Remember that Mold and Algae need a food source such as organic material. Keeping the A/C System clean is your best solution. Proper maintenance is the key to keeping your A/C System clean. Also, not all Air Conditioning Contractors are created equal, some have a vast knowledge of Indoor Air Quality, others have limited knowledge concerning Indoor Air Quality.