Illustration of an office space utilizing upper room GUV in comparison to increased outdoor air fraction, increased air change rate, and improved filtration.
Pacific Northwest National Laboratory (PNNL) research finds upper room GUV is more effective and energy efficient than increased outdoor air fraction or air changes to mitigate COVID-19 transmission in buildings. (Image courtesy of PNNL)

Excellent indoor air quality (IAQ) is an essential feature of healthy buildings. Benefits to the health and wellbeing of building occupants can in turn provide large economic benefits, but design and operation to deliver these benefits may impact building energy use. Germicidal ultraviolet (GUV) radiation, also known as UV germicidal irradiation (UVGI), is a method of air and surface disinfection that may provide effective reduction of virus transmission in buildings without the need for energy-intensive high-ventilation solutions. Emerging GUV technologies represent an opportunity to realize additional energy savings through fixture design and application practices while maintaining the germicidal benefits. Currently, LED GUV sources and fixtures have relatively low efficiency and lifetime but there is headroom to improve through increased source efficiency, improved fixture design, and enhanced reliability. In conjunction with proper ventilation and filtration, GUV is a promising technology for providing optimal IAQ to building occupants.

DOE has engaged leading GUV subject matter experts to better understand the current state of GUV technology and identify critical research priorities. Two R&D meetings resulted in the following reports:

Ongoing research supported by DOE looks to improve our understanding of this emerging technology and its potential to deliver safer, healthier, and more energy-efficient buildings. DOE-supported activities to date include research into UV LED reliability, the effectiveness and energy use of GUV relative to other building mitigation strategies, and a product testing program to ensure commercially available GUV products perform as claimed.

Reliability Testing

Two studies conducted by RTI International examined the initial performance and reliability of LED GUV sources.

  • Initial Benchmarks of UV LEDs and Comparisons with White LEDs (November 2021)
    This study focuses on the construction and initial performance of commercially available UV LED components in radiometric and current-voltage tests. A test matrix containing 13 different UV LEDs was created in association with the LED Systems Reliability Consortium (LSRC).
  • Operating Lifetime Study of UV LED Products (April 2022)
    This study focuses on the long-term performance and reliability of the same set of commercially available UV LEDs. Understanding the failure modes and failure rates of UV LEDs is important in understanding GUV product effectiveness over time and improving UV product reliability at the LED, lamp, and luminaire level. The study employed three stress tests to examine the reliability of each product. Results from stress testing, along with an extensive literature review, identified specific failure mechanisms.

Research into the Effectiveness and Energy Use of GUV Relative to Other Strategies

Pacific Northwest National Laboratory (PNNL) collaborated with researchers at Oak Ridge National Laboratory and Harvard Medical School to review available scientific research on upper room GUV and other HVAC-based mitigation strategies to reduce the spread of COVID-19. This research found upper room GUV a more effective and more energy-efficient alternative to increased outdoor air fraction or air changes using the HVAC system to mitigate COVID-19 transmission risk in buildings. This research study also discusses key limitations and considerations related to the compared mitigation strategies.

CALiPER Product Testing

PNNL is also developing a GUV product testing program for commercially available GUV lamps and fixtures. Testing will provide objective product performance information, evaluate performance claims, inform testing methods and standards, and identify needed improvements. DOE anticipates publishing the first round of test results in 2022, accompanied by a supplemental report that characterizes the current state of test methods, metrics, and testing infrastructure capabilities for GUV product testing.