It’s no secret that ultraviolet light has been used for a long time in treating air, surfaces, and as an effective fighter against bacterial and fungal growth. In fact, UV light has been used since 1900 when it was discovered by a Danish physician Niels Ryberg Finsen for medical use. Seems legit, right? The issue with installing UV bulbs into air conditioning systems or furnaces is the misconception that they’ll treat all the air in the house. UV bulbs can treat air passing through the duct system of your heating and air unit, but the most effective quality they have is in the surfaces that the UV light is touching. An air conditioning system uses two main components to cool your home: an outdoor unit and an indoor cooling coil. The indoor cooling coil is what drops the temperature of the air in your home and also dehumidifies that air. As the air becomes cooler and dehumidifies, water is condensed out of it and is drained outdoors through PVC piping or a condensate pump. A cooling coil can drain up to 20 gallons of water a day out of your home’s air — depending on outdoor air temperatures and humidity levels. That makes for a great place for bacterial and fungal growth to occur and spread. The coil is encased in an insulated cabinet and is dark inside. So, along with being wet and cold already, it’s dark, which mold and mildew love. This growth can cause poor indoor air quality and even odors if left untreated. Installing a UV bulb in an area that touches the cooling coil at all times will kill any growth that tries to take place in that cold, dark, wet area leaving the passing air cleaner and healthier. Instead of thinking the UV bulb will treat the air in your home, we should think about it more as a system treatment that keeps your ducts and cooling coil clean, which will ultimately leave the air passing through your system cleaner. For a low-cost product, UV bulbs are a great way to keep your system clean and treat your indoor air.