Germicidal Ultraviolet Light

There is a great deal of interest in the use of ultraviolet light to mitigate germs and viruses. The technology of germicidal lighting is referred to as germicidal UV, or GUV. Technically, the GUV spectrum is defined as UV-C. While the UV-C part of the spectrum is an effective killer of COVID-19 and similar viruses, it must be used carefully to be both effective and safe. Information on this site is compiled to help promote the safe and effective use of GUV in residential settings.



See a quick guide to UV light, or scroll down for a deeper dive into the topic.

Ultraviolet-C (UVC) Germicidal Devices: Potential Health Risks in Residential Settings


Ultraviolet-C (UVC) Germicidal Devices: Potential Health Risks in Residential Settings


Ultraviolet germicidal devices are rapidly entering the consumer market due to increased demand for sanitizing and germicidal capabilities in the face of COVID-19. But are they all safe? Such UV germicidal products may not be effective and when used improperly can cause damage to eyes and skin as well as to pets, plants, and home furnishings. To explain the potential health risks, the American Lighting Association (ALA), National Electrical Manufacturers Association (NEMA) and UL worked together to provide important safety information about UV-emitting lighting.


“We are pleased to work with NEMA and UL to provide crucial safety information for the public,” says Terry McGowan, FIES, LC, director of engineering and technology for ALA. “The demand for safe, effective UV disinfection technology in residential spaces has led to innovative thinking and is paving the way for the lighting and ceiling fan industries to contribute solutions that will reduce the spread of the disease.”


The new document, “Ultraviolet-C (UVC) germicidal devices: what consumers need to know,” is one of the first official guidelines for the lighting industry and consumers who currently have no assurances of device effectiveness or the risks of over-exposure from devices that do not provide proper containment of UVC emissions.


Key points to know:

  • The COVID-19 virus can only be destroyed by directly exposing it to ultraviolet light in the UVC part of the spectrum which ranges from 200–280 nanometers (nm).
  • LEDs that generate UVC radiation are in development but are currently expensive and not generally available for today’s germicidal products.
  • Disinfection = (UVC Intensity) X (Exposure Time). It is difficult to determine if any portable UV product, such as an ultraviolet wand, is effective if simply moved randomly near objects and surfaces. Direct exposure is also required. UVC light is not visible to the human eye, and when reflected from most surfaces does not destroy germs.
  • Effective and safe UVC disinfection products that can be used in homes include UVC lamp assemblies built into HVAC ducts and permanently mounted wall and ceiling fixtures that direct their UVC light toward the ceiling so that no direct light reaches room occupants or sensitive surfaces and materials.
  • UVC germicidal products can be tested and certified for fire and electrical safety using existing UL and CSA standards, however, there is no product certification and testing process for germicidal effectiveness or human safety from germicidal UV exposure.


For more information about germicidal UV lighting, see and GUV Information Resources, or consult with a lighting expert at an ALA-member showroom. Find home lighting design and buying tips at


The ALA represents the residential lighting, ceiling fan and controls industries in the United States, Canada, and the Caribbean. Member companies include manufacturers, manufacturers’ representatives, retail lighting showrooms and lighting designers with the expertise to educate and serve their customers.


Media contact: Amy Wommack, ALA Communications Manager,, 469-778-7622


Technical information: Terry McGowan, ALA Director of Engineering and Technology,



43457 Rate this article:

Please login or register to post comments.