The surface of air conditioning evaporator coils, and the collection trough under them that the condensate drips into, are areas where mold can grow easily and out-of-sight of a homeowner. Plus, the mold colonies that form release spores that get blown throughout a home in the duct system. 

   An ultraviolet light inside the air handler and duct system that shines on the coils and trough will kill both the mold and its spores on those interior surfaces, but the light takes time—sometimes up to several minutes—to fully exterminate mold. While it will work satisfactorily where it shines directly and continuously, the mold spores floating in the air that are sucked into the system are only exposed to the UV-rays for a fraction of a second as they pass through the air handler. It’s not enough exposure to totally kill the spores, but still may provide some level of airborne spore reduction. A secondary benefit, however, is that the UV-light is quite effective at killing airborne bacteria.

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  To learn more about heating and air conditioning systems, see these other blog posts: 

• My air conditioner won't turn on. What's wrong? 

• How can I find out the size of my air conditioner? 

• Where is the air filter for my central air conditioner and furnace? I can’t find it? 

• Does an old air conditioner use more electricity as it ages? 

• How did homes stay cool in Florida before air conditioning? 

• What is wrong with an air conditioner when the air flow out of the vents is low?

• Why has the thermostat screen gone blank? 

• Why does it take so long to cool a house when an air conditioner has been off for a while? 

• Why is my air conditioner not cooling enough? 

• What are the most common problems with wall/window air conditioners?  

• Will closing doors reduce my heating and cooling costs? 

   Visit our HEATING AND AIR CONDITIONING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.