UV Filters

• Not all ultraviolet light is dangerous. The ultraviolet light produced by black lights for entertainment is actually on a different part of the light spectrum than the hazardous type of ultraviolet light used for sanitation. The dangerous kind of UV light is produced in small quantities by the sun, but can also be created by igniting certain chemicals. When this UV light is strong enough to kill bacteria or mold spores, it is called germicidal UV light.
  
  A UV filter is basically an additional filter that is placed inside your heating and air conditioning system. When you install a UV filter, it is placed on the duct side of the air coils, and exposes all the air that passes through the ducts to a burst of ultraviolet light. This light contains enough energy to break apart the small mold spores with radiation, killing them before they have a chance to create any more mold colonies. The light will also take care of other types of microorganisms like floating bacteria. You will probably have to pay at least several hundred dollars for this system, but in the right conditions it can kill up to 90 percent of bacteria.
  
  

Choosing a UV Filter

• Before you choose a filter, you should learn how many cubic feet of air your home has in it and how quickly this air passes through your ventilation system. This will help you choose a UV system that will expose the air to radiation long enough to be effective at killing mold spores. Some systems are designed to expose slow moving air to a weaker type of radiation for a longer period, while other systems use more intense UV light to treat fast-moving air. Many HVAC UV filter manufacturers use charts that add up the features of the home to give you an idea of what type of system you need.
  
  You should always be very careful with the UV filter and make sure its safeguards are all in place, since the UV light can be very harmful to humans at germicidal levels. You will also want to make sure that your traditional filters are in place and accessible. While the UV light can kill mold spores, the dead spores can still create allergy problems and should be filtered away as much as possible, along with the other particles in the air.