Frequently Asked Questions on Ultraviolet-C (UVC) for Heating and Cooling Systems
Ultraviolet radiation is naturally emitted by the sun. UV radiation in the “C” band range of 200 to 280 nanometers has been widely used as a germicidal control measure in HVAC systems. UV-C destroys mold, yeast, fungus, viruses and bacteria and is often referred to as “germicidal UV.”
UV-C lighting may be installed about a foot above the evaporator coil in a furnace/AC combination system. It may also be installed in the ductwork of an HVAC system, between the blower motor and the air ducts. The particular wavelength emitted by the UV-C lighting targets the DNA of microorganisms, causing cell death and make reproduction impossible… essentially shutting down the spread of dangerous viruses and bacteria. Once the microorganisms are inert, they no longer affect health live tissue.
A properly installed UV-C lighting system can prevent organic buildup in coils, keeping them clean and free of fungus, mold and bacteria. This can lower HVAC operational cost by improving airflow and heat transfer of the coils.
Actual life of a UV-C bulb is 10,000 to 12,000 hours, with a useful life of 8,000-9,000 hours. We recommend the light get changed annually, ideally in spring or early summer so the system will work at peak efficiency during the air conditioning season. We can check the effectiveness of a UV-C system when we perform your annual AC-tune-up in the spring.
Ultraviolet-C radiation, just like A or B wavelengths, can be harmful to people under prolonged direct exposure. In fact, overexposure to UV-A or UV-B, whether through natural sunlight or a tanning bed, is the cause of sunburn. That’s not the case with UV-C, since the devices are installed inside a closed heating and cooling system. So there’s never any direct exposure to your family. In addition, UV-C light cannot pass through glass, so there is no harm to look through and air handling unit access window at UV-C lighting. UV-C, however, is VERY harmful to airborne pathogens like viruses, bacteria and fungus.
UV-C is scientifically proven to render common respiratory viruses inert, including influenza viruses, rhinovirus (the common cold) and common coronaviruses. Since UV-C lighting is commonly installed in medical facilities around the world to prevent the spread of airborne viruses and bacteria throughout HVAC systems, we highly recommend it as a measure to protect your family during flu and cold season.
Please note: neither the Centers for Disease Control(CDC) or the World Health Organization (WHO) have officially announced whether UV-C kills the current strain of Corona Virus (COVID-19)., we urge you to err on the side of caution until we have a definitive answer, and take other measures to prevent the acquisition or spread of this virus.