May 2020 EnergyWiseSM Tip: Ultraviolet Disinfection


 By: Energy Efficiency Program Manager Cory Fuehrer

As we continue to adapt to life with COVID-19, I am reminded of a quote from Winston Churchill’s address to the House of Commons six months before Victory in Europe Day, May 8, 1945: "Now this is not the end. It is not even the beginning of the end. But it is, perhaps, the end of the beginning."

  Indeed, a cure for COVID-19 would provide a beginning to an end. Until that time, we practice social distancing, wear facial coverings and try to stay healthy while cleaning and disinfecting frequently touched surfaces and hands. One technology that helps in the ongoing battle is ultraviolet germicidal irradiation.

 Without getting too scientific, ultraviolet is electromagnetic radiation with wavelengths shorter than visible light. Often, three subsets are referred to: UV-A, which is responsible for skin tanning, UV-B, which is primarily responsible for some types of skin cancer and cataracts and UV-C, which is highly effective for decontamination. UV-C destroys the molecular bonds that hold together the RNA and DNA of viruses and other biological material. Yet limited exposure to humans and the spaces they occupy can be managed without adverse effects.

 For more than 40 years, UV-C has been safely and effectively used in medical facilities, wastewater treatment plants and even residential heating and cooling systems. Along with other disinfection protocols that include air filtration and dilution from fresh sources, contaminants are safely and effectively removed with UV-C. However, because overexposure of UV-C can cause severe, sunburn-like reactions to your skin depending on intensity (and much faster than a regular sunburn, the International Commission on Illumination provides recommended amounts, wavelengths and exposures of UV-C needed to safely disinfect a multitude of different viruses and other organic contaminants. (Please beware that UV-C can also quickly damage the retinas of your eyes if direct exposure occurs.)

 Inexpensive consumer products that produce UV-C have been available for many years. Some have excellent and effective applications, especially in combination with other indoor air and water quality solutions. UV Lights for central HVAC systems are installed through the wall of existing ductwork and use 12 to 70 watts of electricity to provide disinfection for your entire home. Plug-in air purifiers that utilize UV-C technology use 80 to 215 watts of energy to offer single room to whole home coverage.

 But sadly, some vendors of UV-C generating devices misrepresent their products as the best solution to addressing decontamination concerns. With the recent surge of ultraviolet disinfection lights and products on the market, our current crisis is no exception.

 Before spending money on any UV-C technology, consider these points:

 • There are few accepted standards for equipment designed to disinfect with UV-C. As a result, there are many ads and promotions that claim amazing performance with little or no scientific backup.

 • Vendors should be able to cite independent scientific studies documenting the effectiveness of their device. The scientific report should illustrate the actual reduction of test microorganisms using their product over a given time and exposure distance.

• Legitimate manufacturers should be registered with the U.S. Environmental Protection Agency as a pesticide and/or device-producing establishment. You can check their website at: 

• Determine if the device has built-in UV safety sensors for automatic shutoff. If not, is safe operation totally reliant on the operator?

• Check to see if the device meets NIOSH, UL, IEEE or other related safety standards. 

• Remember that UV disinfection is based on "line-of-sight" between the UV lamp and the target surface. If the UV-C beams are blocked by other objects or shadowed by texture on an uneven surface, satisfactory disinfection may not occur. Consider what and where you will disinfect with the device.

• Some devices also produce ozone as part of their operation. Be sure you understand the human safety concerns associated with this gas before operating.

 Southwest Public Power District, in partnership with Nebraska Public Power District, wants you safe, now, and in the future. That includes helping assess technologies that purify our air and water. For ways to help with the cost of efficiency improvements, visit with Southwest Public Power District or



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