UV lights are becoming increasingly common in HVAC systems, especially in the wake of the Coronavirus pandemic. How do they work? Are they worth the investment?
In the past few months, some buildings have installed UV lights for their HVAC systems, spurred by studies that prove that ultraviolet light and UVC radiation can be effective in inactivating the SARS-CoV-2 virus, as well as other airborne viruses. Results in Florida indicate that these can be used along air filters and other preventive measures to reduce the transmission of Covid-19, even though UV lights are not a silver bullet against this disease.
However, they are still effective at improving the overall indoor air quality. The most widespread application of UV light is for germicidal purposes and very specifically in coils, to keep them clean, free of algae, mold or fungi. This helps to maintain their thermal efficiency and avoids the use of germicides in the condensate trays.
Another use that has become more known in the past year in the wake of the pandemic, is the elimination of the biological load of the air, which means that ultraviolet radiation can eliminate airborne microorganisms responsible for allergies, viruses, and other ailments. To achieve this, it’s necessary to determine what these organisms are and in what quantities they are found, to determine the “dose” of radiation required.
It is also possible to use UV light as an aid in the treatment or elimination of unpleasant odors. In this case UV light lamps are used to generate ozone, which is injected into the air conditioning system. In this application the most important aspect to consider is the amount of ozone to be produced because we must not exceed exposure limits, to avoid endangering the health of users or occupants. This same technology is used for the dilution of some pollutants.
For home users who want to install UV lights, the first step should be consulting your AC technician, so they can determine the best place to install an UV lamp on your HVAC system. These are usually placed in the coils or the ducts.
Finally, if you decide not to install UV lights, you can keep the air quality high with other measures, such as changing your air filter consistently, sealing up any air leaks, keeping your air handler, outdoor unit and indoor coil clean and free from debris, and cleaning your air vents and registers from time to time.
