How UV Lighting Can be Used as a Disinfectant for Your Facility
iSi can now provide disinfecting UV lighting for your HVAC system.
UV lighting can be used as another tool in your safety and environmental arsenal to make your workplace safer and healthier. But how does it work?
TL;DR: UV-C light (254 nanometers) kills germs, mold, and airborne microorganisms by damaging their DNA/RNA, preventing replication. It works in two ways: placed near air vents to treat circulating room air, or installed directly in HVAC systems to disinfect coils and improve system efficiency. Proper placement prevents direct occupant exposure while maximizing germicidal effect.
What’s at Risk: Contaminated HVAC systems harbor mold and pathogens that circulate throughout your facility, triggering respiratory complaints, sick leave spikes, and potential OSHA General Duty Clause citations for unsafe air quality. Airborne microbial loads also increase product contamination risk in food, pharmaceutical, and medical device operations. Without active air treatment, indoor air quality becomes a compliance and productivity liability—especially in high-density occupancy facilities.
What is UVGI?
Ultraviolet Germicidal Irradiation, or UVGI, is a technology that goes back to the 1930’s with studies showing that ultraviolet light has the ability to kill or inactivate airborne microorganisms. These studies showed that an optimal wavelength of 265 nanometers (nm) was able to provide the largest reduction in airborne microorganisms. This was found to be very close to the wavelength produced by low-pressure mercury vapor lamps (254 nm). Ultraviolet light can be broken down into 4 different bands: UV-V: 10-200 nm, UV-C: 200-280 nm, UV-B: 280-315 nm, UV-A: 315-400 nm. The sun emits the full spectrum of ultraviolet light but only UV-A and UV-B make it to the surface. The others are filtered out by the Earth’s atmosphere. The UV-C band is the most effective at attacking the harmful microorganisms, so it needs to be generated artificially.
How does UVGI work?
UV-C wavelengths are readily absorbed by the DNA and RNA of microorganisms such as germs and mold. When absorbed, UV damages their DNA or RNA structure, preventing the microorganism from replicating. The magnitude of their reduction is affected by their resistance to UVGI, the quantity of UV energy delivered, and the type specific microorganism being irradiated. Disinfecting light is delivered in two common methods. The first is by placing light units, either with or without fans, near the top of a room close to the air vents in order to clean the air as it circulates the room. The second method is to place the unit directly into the heating and air conditioning (HVAC) system. This second method places the light in a location where the room occupants are not directly exposed to the light, and if placed correctly, can have an added advantage of cleaning the HVAC coils and drip pan to improve the efficiency of the HVAC system.
UV Safety Considerations
UV-C band light is a safer band than the UV-A and UV-B that we deal with in nature. Due to the shorter wavelengths UV-C will only penetrate the outer skin layers and along the surface of the eye. It will not give you the severe sun burn the longer wavelengths will. It will cause a reddening and slight irritation of the skin and a painful itching sensation that will last a few days in the eye so slight protection is required if you are directly exposed to the light from these units.
If you’re concerned about indoor air quality, employee respiratory complaints, or mold growth in your HVAC system, UV-C retrofits offer a low-maintenance, scientifically proven solution. A baseline facility assessment identifies high-risk areas—humid zones, HVAC drain pans, high-occupancy rooms—where UV-C installation delivers the fastest ROI. iSi Environmental conducts air quality audits, recommends HVAC-integrated or room-based UV-C placement, and handles installation coordination. Many facilities see reduced sick leave within 4–6 weeks of activation, plus extended HVAC coil life and lower maintenance costs.
Frequently Asked Questions
Q: What is UVGI and what wavelength is most effective for disinfection?
Ultraviolet Germicidal Irradiation (UVGI) uses ultraviolet light to kill or inactivate airborne microorganisms. Research dating to the 1930s established that an optimal wavelength of 265 nanometers provides the largest reduction in airborne microorganisms, close to the 254 nm wavelength produced by low-pressure mercury vapor lamps. UV-C (200-280 nm) is most effective at attacking harmful microorganisms but requires artificial generation.
Q: How does UV-C light kill microorganisms?
UV-C wavelengths are readily absorbed by the DNA and RNA of germs, mold, and other microorganisms. When absorbed, UV-C damages the DNA or RNA structure, preventing the microorganism from replicating. The effectiveness of disinfection depends on the microorganism’s UV resistance, the quantity of UV energy delivered, and the specific organism being irradiated.
Q: What are the two common methods for delivering UVGI disinfecting light?
The first method places light units near the top of a room close to air vents to clean circulating air. The second method places units directly in the HVAC system, preventing direct occupant exposure while also cleaning HVAC coils and drain pans to improve system efficiency. Placement in the HVAC system provides the safest application for facility occupants.
Q: What are the safety considerations for UV-C light exposure?
UV-C is safer than natural UV-A and UV-B because its shorter wavelengths only penetrate outer skin layers and eye surfaces, not causing severe sunburn. However, direct exposure can cause skin reddening and slight irritation, plus painful eye itching lasting several days. iSi Environmental recommends slight protective measures if directly exposed to UV-C light units.
UV-C assessments and installations start at $1,200 for a baseline air quality audit with HVAC placement recommendations. Full HVAC-integrated UV-C retrofits with installation run $2,500–$6,000 depending on system size and facility layout.
Need help with air quality compliance and UV-C disinfection? Contact iSi Environmental for a same-day quote, or explore our industrial hygiene and environmental services to see how we can help your facility.
We Plug In. You Level Up.