Contractors, take note: Commercial property professionals are finding that high-intensity ultraviolet germicidal irradiation (UVGI) helps improve air quality for tenants and their employees, while streamlining maintenance and boosting rental rates. This opens up real new opportunities for their mechanical contractors and building maintenance professionals.

Property and human resource professionals are finding that they have a valuable tool in a new type of UVGI light that may be the key to preventing sick building syndrome (SBS), lowering operating costs, and boosting both staff productivity and rental rates. In this market, they need all the help they can get.

SBS is often blamed for a range of health problems including irritation of the eyes, throat, and nose; respiratory illnesses such as asthma; and headaches, fatigue, and problems concentrating. The cause of these and other ailments can be traced to the microbial content in the air people breathe inside the building, brought about, in part, by building designs that close the building off to outside air.

High-intensity UVGI shines at an intensity that’s effective in penetrating the cell membranes of targeted microorganisms, breaking their DNA structure and inhibiting reproduction. By continuous exposure of high-intensity UVGI to areas susceptible to mold or microbial growth, such as air conditioning coils, such growth can be virtually eliminated. It can also help burn off particulate lodged inside air conditioning systems to increase airflow while reducing energy use - a definite benefit contractors can offer.

Research indicates that high-intensity UVGI can be an effective means of improving IAQ by preventing mold, bacteria, or microbial growth in air-cooling units, air conditioning coils, and drip pans, which are prone to moisture-related growth, especially in humid climates.


An adequate reflector will direct UV light, preventing the loss of energy out the top, bottom, or back of the lamp, and directing a larger portion onto the air conditioning evaporator cooling coils or drip pan.

By directing the UVGI in one direction, the parabolic reflector virtually doubles the lamp replacement time, which reflects directly on maintenance costs for both the UV lamp and the labor associated with replacing the lamp. The parabolic reflector also protects plastics and wiring from destructive UV rays, and offers protection from breakage caused by high air velocity vibration.

In a study published in The Lancet medical journal, McGill University scientists found that shining high-intensity UVGI purifiers manufactured by Sanuvox Technologies on the air conditioning coil reduced overall sickness by 20 percent, reduced respiratory symptoms by 40 percent, and resulted in a 99 percent reduction of microbial and endotoxin concentrations on irradiated surfaces within the ventilation system.

According to the study, “Installation of UVGI in most North American offices could resolve work-related symptoms in about 4 million employees, caused by microbial contamination of heating, ventilation, and air conditioning systems. The cost of UVGI installation could, in the long run, prove cost effective compared with the yearly losses from absence because of building-related illness.”

The study added, “Since UVGI eliminated almost entirely all surface bacteria, fungi, and endotoxin, the nonspecificity of this technology means that it could provide source control without having to first characterize the microbial contaminants.”


According to Michael Copp, chief engineer at Travis Commercial, a San Antonio, Texas-based full-service commercial real estate firm, particulate had lodged in the coils of some air conditioning units at one property, diminishing their full capacity.

“Instead of chemical treatment and pressure washing, which tended to push particulate to the center of the coil, we implemented a Sanuvox CoilClean UVGI purifier to open the airflow, reduce energy use, and improve indoor air quality,” he said.

“We achieved 35 percent better airflow within the first month-and-a-half on one air conditioning coil,” Copp explained. “The high-intensity UVGI, focused by the parabolic reflector, is helping to burn out anything plugging up the coil. We’re getting greater air movement and heat exchange surface, which is cutting energy use - all without the use of chemicals.”

Another benefit, according to Copp, is eliminating labor and human error, a potential source of liability, from the maintenance process. Routine pressure washing and chemical treatment is no longer needed for the air conditioning coil, since it receives 24/7, high-intensity UVGI purification.

“We’re on track for one-year ROI on the UVGI purifier, and it could be much quicker when you add energy and potential insurance savings,” said Copp, who plans UVGI implementation on air conditioning units throughout the rest of the building shortly. “Along with other amenities, UVGI purification of air conditioning coils can help make the difference between a Class A and Class B property, which can substantially boost rental rates.

“Breathing cleaner, fresher air helps keep employees healthier and more productive, which helps our tenants,” he said. “This helps to keep our managed properties occupied and productive, which along with streamlined maintenance, adds to the bottom line.”

James Mackinder has successfully used UVGI purifiers to control mold and microbial growth on air conditioning coils. A mechanical engineer in Jacksonville, Fla., with decades of HVAC experience, Mackinder said, “The UVGI has improved air quality and reduced maintenance. I’ve noticed fewer people out sick, and we get more uptime on the air conditioning units, which is important in our 24/7 environment.

“Dirty air conditioning coils actually got cleaner with the parabolic reflectors directing UVGI energy on them,” he added. “We haven’t had to clean the coils since putting in the purifiers about two years ago. We’re breathing cleaner air and working more comfortably and efficiently.”

Publication date:04/20/2009