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Many people want to know if HVAC UV bulbs really work to improve indoor air quality in heating, ventilation, and cooling (HVAC) systems. HVAC UV light bulbs can be highly effective at killing bacteria, viruses, mold, mildew, and fungi when using the right type of germicidal UV bulbs and with the proper installation.

Do HVAC UV Bulbs Really Work?

HVAC UV light bulbs prevent the accumulation of harmful microbes on internal components such as heat transfer coils which are exceptionally vulnerable to contamination due to the dark environment combined with condensation. Using HVAC UV light bulbs helps to improve the condition of mechanical components and reduce necessary maintenance by maintaining clean and sanitary parts free from microbial buildup.

HVAC UV bulbs also improve indoor air quality by sanitizing the air and inactivating mold spores that pass through HVAC ductwork. Ozone lamps in HVAC systems can also reach where direct UV exposure cannot and eliminates volatile organic compounds (VOCs) and foul odors from the air. Using UV bulbs in HVAC systems helps prevent harmful microorganisms from circulating throughout the ductwork in your home or office.

UVC Germicidal Bulbs for HVAC

HVAC UV light bulbs must be UVC germicidal bulbs to provide sterilization effectiveness. Ultraviolet light includes wavelengths in the range of 100 to 400 nm and is divided into three bands:

UVA is the longest wavelengths at 315 to 400 nm
UVB is in the range of 282 315 nm
UVC wavelengths are in the range of 100 to 280 nm

UVC radiation, specifically in the range of 254 nm, is proven highly effective at eradicating microorganisms quickly upon exposure by altering the DNA and preventing harmful germs from replicating. UVC radiation in this wavelength is proven to eliminate many types of harmful viruses and bacteria, including stubborn antibiotic-resistant bacteria and harmful coronaviruses, including the SARS-CoV-2 virus that causes COVID-19.

Far UVC is an even shorter wavelength in the range of 222 nm and is also effective for surface and air sterilization applications, and is safer for human exposure. 254 nm lamps are used in many surface, water, and air sterilization applications, although they should not be used in direct contact with human exposure. 222 nm lamps are providing alternative solutions with effective sterilization and safer usage.

HVAC UV Bulbs Improve Indoor Air Quality

UVC lamps for HVAC systems improve indoor air quality when installed by a professional to ensure safe and effective installation. HVAC professionals have knowledge of the correct placement and direction of UV bulbs for effective sterilization, considering the humidity and temperature levels in the home. Upper-Room Ultraviolet Germicidal Irradiation (UVGI) systems are located above occupied spaces and kill airborne pathogens for cleaner, healthier air.

UVGI and Air Filtration Filters

The Centers for Disease Control and Prevention, CDC, recommends a layered approach with the proper ventilation to mitigate the spread of disease and lower exposure. Using High-Efficiency Particulate Air (HEPA) is important to trap larger particles which could shield microorganisms from UV radiation, reducing effectiveness. UVGI provide effective sterilization but should be used in conjunction with proper air filtration and cleaning measures, and they do not replace the need for HEPA filtration.

HVAC UV Light Bulb Systems

HVAC UV bulbs provide two different types of sterilization, cleaning the coils and equipment for longer-lasting, cost-efficient operation and air sterilization in HVAC ducts. UV bulbs for HVAC disinfectants sterilize the air as it cycles through return ducts. Interior reflective surfaces maximize UVC light effectiveness in all directions. For sterilizing coils, UVC lamps are installed to target vulnerable components, including coils, filters, and condensation pans. UV light for HVAC systems prevents microbial growth in hard-to-reach places, including seams, grooves, and edges.

The ongoing COVID-19 pandemic continues to stress the importance of utilizing effective Infection Prevention and Control (IPC) methods, and germicidal lamps are gaining in popularity as UVC virus killers. Ultraviolet (UV) based technologies are promising IPC tools showing high efficacy in killing many types of beta coronaviruses, including the SARS-CoV-2 virus that causes COVID-19.

As of March 29, 2023, the toll of the global health pandemic as reported by the World Health Organization, WHO, reports 761,402,282 confirmed cases of COVID-19, including 6,887,000 deaths in 229 countries and territories and 102,697,566 confirmed cases of COVID-19 with 1,117,054 deaths in the United States.

UVC Virus Inactivation and Efficacy in Reducing the Spread of Disease

The Federal Drug Administration, FDA, offers additional information for businesses and consumers to learn more about ultraviolet light virus inactivation and its efficacy in reducing the spread of disease. UVC radiation at the correct wavelength has been used for decades for the effective disinfection of air, water, and surfaces and is engineered in UVC germicidal lamps. UV-C light kills bacteria such as tuberculosis and many viruses, including beta coronaviruses.

UV-C Light Kills Viruses MERS, SARS, and SARS-CoV-2

Coronaviruses are a large family of viruses that typically cause mild-to-moderate respiratory infections in humans, although coronaviruses are known to infect both humans and animals. They can often spread in animals but can jump to humans and continue spreading in humans with viral mutations. Coronaviruses are named partly due to the crown-like spiked protrusions on the surface.

Some types of coronaviruses may cause illnesses like the common cold, although severe acute respiratory syndrome viruses (SARS-CoV) can be severe, such as the fatal outbreak of SARS in 2002 and Middle East Respiratory Syndrome coronavirus (MERS-CoV) in 2012. SARS-CoV-2 is another severe acute respiratory syndrome virus that causes COVID-19.

Ultraviolet light virus inactivation is highly effective at eliminating the threat of coronaviruses, including the SARS-CoV-2 virus, when administered at the proper wavelength and dosage. According to a scientific report, UV-C irradiation is highly effective in inactivating SARS-CoV-2 replication; the response of UV virus inactivation depends on both the virus concentration and the UVC dose. The results of this study and many others show that the SARS-CoV-2 is extremely sensitive to UVC light.

UVC Light Kill Viruses And Other Harmful Pathogens

According to a study published in 2020 and reported by Biological Consulting Services, UVC virus inactivation was determined against various harmful pathogens with results including:

Influenza A H1N1 – 99.999% reduction
SARS-CoV-2 virus – 99.999% reduction
Polio Virus LSc 1 – 99.99% reduction
Methicillin Resistant Staphylococcus Aureus (MRSA) – 99.99 reduction
Salmonella species, 6 variations – 99.99% reduction

UV virus elimination is very effective when using the right type of UVC germicidal lamps and the proper dosage, and environment such as line of sight disinfection on a surface not contaminated with dirt that can affect UV inactivation results. This is why ultraviolet light virus disinfection is recommended in addition to manual cleaning practices for maximum effectiveness.

UVC Virus Disinfection in Air, Water, and Surfaces

UVC germicidal lamps are typically designed to emit wavelengths at precisely 254 nm, proven to be highly effective at penetrating the DNA of microorganisms to render them harmless. Far UVC lamps are gaining in popularity and showing high germicidal efficacy while being safer to operate in the presence of humans. Standard germicidal UVC lamps should operate in non-occupied spaces and can be found in upper room ultraviolet germicidal irradiation (UVGI) systems, HVAC systems, and other disinfection devices like UVC robots programmed to run through hospital hallways or patient rooms that are unoccupied.

Not all UVC germicidal lamps are created equal, and it is important to work with an experienced ultraviolet lamp designer to ensure effective germicidal properties.