Preparing your fleet for aerial disinfection with UVGI

Modes of transportation like school buses and vans create a vector of infection that is often overlooked. “The probability of infection on airplanes Is similar to the likelihood in tour coaches and school buses,” thus presenting the possibility of increased infection rates, particularly during longer transit times.

When Steril-Aire Ultraviolet Germicidal Irradiation (UVGI) solutions are placed in the mode of transportation’s HVAC system, they will predictably disinfect cabin air while reducing maintenance and energy costs of the system. ‘unity.

“A single control strategy usually cannot provide adequate protection for occupants. It is necessary to integrate several strategies.


There are three proven solutions for airborne disinfection: Ventilation, Filtration and UVGI.

These solutions are peer-reviewed and backed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the American Green Building Council, the US Environmental Protection Agency (EPA) and many others. When these solutions are used together, disinfection results become more meaningful and risks are significantly reduced.

For example, in a school bus that has a naturally high rate of air changes per hour, or ACH, (typically 20-50), the effectiveness of Steril-Aire UVGI is greatly increased due to the amount of air which can go through the UVC Solution within the given time. While the likelihood of COVID-19 infection isn’t exactly clear, studies have shown school buses have more than 20 times the acceptable risk rate. For most spaces, the risk of infection can be reduced to less than 0.1% using the discussed peer-reviewed solutions.

Typically, HVAC systems in buildings are often equipped with UVGI systems to clean the coils, sanitize the air, and provide energy savings using ASHRAE’s Indoor Air Quality (IAQ) principles. These principles can be applied to school buses and subway buses because the internal HVAC system is constructed similar to a building.

As shown in the “Innovations Programs Deserving Exploratory Analysis (IDEA) – Ultraviolet Germicidal Irradiation for Transit Buses” study, energy savings and IAQ improvements can be achieved with the installation of UVGI. Here are the main points of this study.

The IDEA – Ultraviolet Germicidal Irradiation for Transit Buses programs had two main objectives:

  1. Apply UVGI systems to Carrier and Thermo King (Trane) HVAC systems to determine the effectiveness of improving indoor air quality by eliminating pathogens
  2. Recognize and quantify cost savings associated with energy reduction of clean cooling coils and reduced maintenance of bus HVAC systems through UVGI

The application results of this study were similar to the IAQ results of your general building’s HVAC system. More specifically, testing show 99% reduction in common viruses and 95-99% reduction in mold, fungus and bacteria on buses.

By eliminating these harmful pathogens from buses, one can see less driver absenteeism, improved productivity, less overtime, fewer complaints from student passengers, and other IAQ benefits. While not only creating IAQ benefits, disinfection of HVAC coils will create energy savings that typically provide a payback in approximately 18 months, thus paying for itself in a short period of time.

Predictable maintenance savings occur in several ways:

  • Evaporator maintenance savings
  • Reduced cleaning chemicals and disposal costs
  • Fewer air filter and component replacements
  • Less out-of-service costs

The Houston Metropolitan Transit Authority calculated savings from reduced maintenance and estimated cost savings for 100 buses. In today’s dollars, this value would be approximately $180,000 or $1,800/bus.

For buses that operate in “no reheat mode”, there is also a fuel economy. Based on 100 buses, 300 days of operation, and diesel fuel at $5.50 per gallon (average price in June 2022), the estimated total annual savings would be $66,000 or $660 per year per bus. IAQ improvements in buses can create lasting and substantial cost savings for your fleet.

At Steril-Aire, our customers and partners have trusted our expertise in disinfection and IAQ for over 30 years. In fact, although other companies have also begun to offer Ultraviolet Germicidal Irradiation (UVGI) solutions, Steril-Aire holds the original patent for UVGI disinfection in HVAC applications.

To achieve the IAQ benefits of UVGI, a best practice is to install an enhanced UVC kit from Steril-Aire in your buses. These UVC kits are easy to install into your current HVAC systems and can be powered by DC or AC power supplies. EUVC kits come with an IP67 waterproof connector and are compatible with any length of Steril-Aire emitters. The lifetime of the Steril-Aire emitter is approximately 9,000 hours and approximate replacement is one year. Once installed correctly, no maintenance is required.

These solutions are a “subtractive” technology according to the US Green Building Council, meaning they don’t generate ozone or add anything to the air, making the air safer for drivers, students and the environment.

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