Residential ultraviolet duct disinfection systems arrived on the market about 1995. These are the standard ‘UV stick lights’ that most contractors are familiar with.

They operate on the 253.7-nanometer germicidal C-band wavelength and are very effective for destroying germ carrying microbes and bacteria in the ductwork. “Everyone’s using UV-C. It’s a very effective wavelength for disinfection,” noted Aaron Engel, vice president, business development for Fresh Aire UV Canada, Montreal.

Offering a proven solution

Products at the low end of the spectrum tend to be ‘bare bones’ models with few features

Over the past ten years, advances in ease of installation and safety have continued to increase the viability of UV-C (in multiple applications),” added Daniel Jones, president and co-founder of UV Resources, Santa Clara, California. FEP (fluorinated ethylene propylene) coated lamps offer protection from breakage and better fixtures allow 360-degree irradiance and easier installation, noted Jones.

And the price has come down considerably. Not surprisingly, products at the low end of the spectrum tend to be ‘bare bones’ models with few features. “For most contractors the UV light tends to be a pretty challenging sell without the homeowner understanding the benefits,” noted Greg Butt, executive director for Emerson Commercial and Residential Solutions (formerly White Rodgers), Richmond Hill, Ontario. But where the homeowner is experiencing indoor air quality (IAQ) issues, UV offers a proven solution.

Photo catalytic oxidation

The second commonly used ultraviolet technology is UVV, which operates on a 187-nanometer wavelength and destroys odors and chemicals – VOCs, or volatile organic compounds. “It’s very effective,” noted Jocelyn Dame, president, Sanuvox Technologies Inc., Montreal. Many two-lamp systems consist of a UVC and UVV lamp – in fact Sanuvox puts both into the same lamp – to control both biological contaminants and VOCs. UVV lamps produce ozone.

However, the amounts are small, typically about .03 ppm when measured 10 feet from the lamp and well within the U.S. Environmental Protection Agency (EPA) maximum safe ozone level of .05 ppm. The newest UV technology is photo catalytic oxidation (PCO). Basically, it works by shining UV light on a titanium substrate – a grid or a cartridge – causing a catalytic reaction that destroys chemicals and odors.

Downstream of the evaporator coil

The UV reacting with the titanium breaks up VOCs into carbon dioxide and water

Fresh Aire UV’s APCO (advanced photo catalytic oxidation) system, for example, is a non-ozone producing system that uses UVC light that reacts with activated carbon impregnated with titanium to adsorb odors and sterilize the air and coil.

Activated carbon can only adsorb so much before it becomes saturated. However, the UV reacting with the titanium breaks up VOCs into carbon dioxide and water, so they are safely released from the carbon. The carbon is, in effect, constantly regenerating itself, explained Engel. A UV lamp can be installed almost anywhere in the ductwork. However, most manufacturers suggest placing it either downstream of the evaporator coil or in the return duct, where air movement is slowest. The critical factors are UV light density and dwell time – how long the contaminants are exposed to UV.

Breeding ground for microbial growth

In a coil installation, the lamp is placed perpendicular to the airflow and parallel to the coil. It’s a good location because “It’s wet, it’s cool, it’s dark; it’s the perfect breeding ground for microbial growth,” said Engel. “You can show me what will appear to be a clean and dry coil… and if I did a petrie dish test, a contact test or a culture on it, there would be more often than not microbial growth on that coil.”

If you install a UV system over that evaporator coil, you will be able to keep it clean, keep it sterile and keep the drain pan clean. As the air moves up through the coil, you are able to address the air quality as the air passes the UV light.”

Compensating for the faster airflow

On a supply side installation, a larger lamp might be used to compensate for the faster airflow

Installing the UV lamp in the return air duct also has a number of things going for it. The air is moving at it’s slowest, which increases dwell time. And if the lamp is installed parallel to the airflow, that maximizes the dwell time and has the side benefit that the lamp remains cleaner because airborne ‘gunk’ is less able to stick to it.

This allows Sanuvox, for example, to recommend that UV-C lamps mounted in this fashion to be replaced only once every three years. “Now we have an air purifier and not just an object purifies,” added Dame. It’s not always possible to install the UV lamps in the most ideal location. On a supply side installation, a larger lamp might be used to compensate for the faster airflow. All manufacturers offer sizing charts that will help. Some also have smartphone apps to assist the technician.

Providing disinfection on both sides

The installing technician must keep in mind that these are ‘line of sight’ devices, so any obstruction between the lamp and the surface to be disinfected will block the irradiation. Often a two-lamp system would be installed over the A-coil to provide disinfection on both sides, noted Butt.

As well, he added, it may seem obvious but the technician needs to be absolutely sure where the coil is located before they cut the hole in the ductwork so that the UV lamp is installed in the optimum position. Easy access to the UV lamps once they are installed is critical, noted Jones. This includes ensuring any switches or wall plugs are readily accessible to turn the system off or service. As well, UV can damage plastic or paper where it does not contain UV inhibitors.

Packaged connected home system

Some manufacturers have added Wi-fi connectivity to certain UV lamp modelsMost plastic drain pans do these days and if there’s no option but to place the lamp near the furnace filter, there are also UV resistant filters. Any exposed wire should be wrapped with metallic tape. Today’s smart controls help the different equipment in the home to work in harmony, maximizing comfort and efficiency. Increasingly, UV systems are being integrated.

Some manufacturers have added Wi-fi connectivity to certain UV lamp models. This allows the homeowner to check things like lamp life on their smart phone. In January, Fresh-Aire UV introduced its AirSmart packaged connected home system at the AHR Expo in Las Vegas. It consists of their APCO UV system, a Foobot indoor air quality monitor (sensor control) and a Lux Wi-fi hermostat. The Foobot continuously monitors the air on many different variables including temperature, humidity, particulate, VOCs, etc.

Significant source of income

Any time there is a spike or issue, it notifies the thermostat, which turns on the furnace fan to ‘clear the air,’ as it were. The homeowner can see exactly what effect activities like cooking, painting or construction materials gassing off have by watching their smartphone. IAQ has been largely subjective in the past; now they have reliable data.

With the homeowner’s permission, the contractor can log into the device to check the IAQ in a customer’s home and adjust the HVAC equipment if needed. The contractor needs to educate the homeowner. While most UV lamps have safety features, “It is wise to warn about detrimental effects of UV-C exposure to the skin and eyes,” noted Jones.

And, of course, homeowners need to know about lamp replacement intervals. Too often, says Dame, the contractor does the initial installation and never comes back. “They are giving up a significant source of income. They should be selling the lamps and sending reminders to their customers when they need to be replaced.”

Share with LinkedIn Share with Twitter Share with Facebook Share with Facebook
Download PDF version Download PDF version

In case you missed it

HVAC Companies in the News as Cold Weather Pummels United States
HVAC Companies in the News as Cold Weather Pummels United States

Deadly cold weather recently made headlines in Texas, where wintry conditions knocked out power to around 4.5 million homes at one point. Power outages, combined with freezing conditions, sent Texans scrambling for home heating alternatives, such as generators and fireplaces, and to seek shelter in powered warming centers or businesses. Some resorted to living in running cars. Snow, ice and extreme cold have been widespread this year in the Mid-Atlantic and Northeast United States, too. At one point, 78 million Americans were under a winter weather alert, and more than 27 million were under a hard-freeze warning. More than 2,500 new records were set for lowest high temperatures. At least 38 people nationwide died from winter storms or frigid conditions. Additional Challenges for HVAC Industry For HVAC companies, the cold weather means more business, and additional challenges to serve their customers' needs. Local TV stations often turn to HVAC installers to provide commentary and insights about their surge in business brought on by Mother Nature.Sub-zero weather translated into below-freezing indoor temperatures for some HVAC customers In Lincoln, Neb., for example, sub-zero weather translated into below-freezing indoor temperatures for some HVAC customers whose furnaces were not running. Many of the systems had been badly maintained, operated inefficiently, and/or were beyond their life expectancy. “We’ve had some guys that have houses that their furnaces aren’t running, we’ve had some houses at 31 degrees, 34 degrees,” said John Henry’s HVAC Service Technician, Thaddeus Bertsch, interviewed by 10/11 KOLN News. Issues with Frozen Pipes "As [cold weather] goes on, we are starting to get more calls for frozen pipes," adds Keith Jackson with Jackson Plumbing, Heating, and Cooling, Decatur, Ala. "People have no water," he told WZDX Fox News. HVAC technicians stay extra busy working in the snow and dropping temperaturesAlso, outdoor heating and AC units were shutting down. The units were freezing up, and frozen rain and ice affected the operation of the outside condensers. The company had crews out trying to help people with frozen pipes across Decatur and beyond. HVAC technicians stay extra busy working in the snow and dropping temperatures. For instance, business tripled for Jarboe’s Heating, Plumbing and Cooling in Louisville, Ky. Field technicians were working longer hours because of heaters going out, reported WDRB News in Louisville. "As soon as the phones are open, they’re ringing" For two days in February, by nine o’clock in the morning, J.E. Shekell Inc. in Evanstan, Ind., already had received over 30 service calls. "As soon as the phones are open, they’re ringing,” said Jim Poag of J.E. Shekell Inc. A report by WFIE 14 News in EvanstanFrigid temperatures cause furnaces to work extra hard to keep houses warm highlighted how frigid temperatures cause furnaces to work extra hard to keep houses warm. Depending on how well they are maintained, and how old the machine is, it can sometimes be too much. “We’ve been getting a lot of calls, several, you lose count after a while, just trying to help as many people as we can right now. It’s probably about my seventh call of the day so, we’re out trying to help as many people as we can,” said John Hambleton of Lyerla Heating & Air, Joplin, Mo. Dangerous temperatures and winds Lyerla Heating and Air received 300 service calls in just two days on Feb. 15-16. Like many of the local media reports, KSN News in Wichita, Kan., emphasized the need to prevent untimely breakdowns by getting units serviced before dangerous temperatures and wind chills set in. Staff at Wiersgalla Plumbing & Heating, Eau Claire, Wis., says service calls had risen roughly 25% when the cold rolled in. Staff worked extended hours to fix broken heaters and frozen home exhausts. "Over the last week and a half, we've experienced an increase in calls obviously because of the cold," said Christina Wiersgalla, VP of operations for Wiersgalla Plumbing & Heating, Eau Claire, Wis., in a report by WQOW 18 News. Among the consequences of brutal winter weather are a greater appreciation of the work of HVAC companies and an opportunity to shine a spotlight on how they keep customers comfortable in their homes and businesses.

Lessons From The Past: The Value Of Ventilation In A Pandemic
Lessons From The Past: The Value Of Ventilation In A Pandemic

If history truly repeats itself, might we learn lessons from the past – even lessons about managing a novel coronavirus that upends our way of life and changes the world forever? The most commonly cited parallel to the COVID-19 pandemic is the Spanish flu pandemic of 1918. Both diseases are caused by viruses that had not been seen before. In both cases, no one had immunity to a highly infectious germ that was spread through respiratory droplets. Both outbreaks occurred in multiple waves over several years. Furthermore, in both cases, it became clear that ventilation, fresh air, open spaces and sunlight are useful factors in promoting good health. Fresh Air Movement During the time of the Spanish flu, there were signs posted in buses and throughout New York that advised: "Keep your bedroom windows open [to] prevent influenza, pneumonia [and] tuberculosis." There was even a national campaign known as the “Fresh Air Movement,” calling for people to be outside more, and urging greater ventilation indoors. The movement included a kind of traveling show that spread the word about the “national poison,” which was the result of people breathing stale air inside closed rooms. These concerns predated by decades our enthusiasm for “indoor air quality.” In became common after 1918 to position radiators providing steam heat under open windows to combine warmth with fresh air, even on the coldest of days.   The Open-Air Treatment of Pandemic Influenza It was also common practice by 1918 to place the sick outside in tents or in specially designed open wards But the advantages of fresh air go back even further, as described in a 2009 article in the American Journal of Public Health (AJPH) titled “The Open-Air Treatment of Pandemic Influenza.” During the 1918 pandemic, as today, many cities banned public assembly, closed schools, isolated those infected and mandated the wearing of face masks. It was also common practice by 1918 to place the sick outside in tents or in specially designed open wards, according to the AJPH article. The practice dates back to English physician John Coakley Lettsom (1744-1815), who was among the first advocates of the “open-air method.” The 1800s saw emergence of tuberculosis sanitoriums, which treated the lung disease with a combination of fresh air, gentle exercise in the open, nutrition, and a minimum of medicines. Lack of ventilation Spending time in well-ventilated houses in the country became seen as superior to patients being confined to warm, badly ventilated rooms to protect them from the supposedly harmful effects of cold air. Lack of ventilation forced patients to breathe foul air, contaminated with germs, over and over. Research later confirmed the importance of measures to prevent influenza virus from spreading through buildings. Improvements in air-handling equipment, portable filtration units, and introduction of physical barriers and other partitions or doors also provided protection. These lessons were clear long before the advent of the novel coronavirus that causes COVID-19. Their successful deployment during the pandemic have further supported their value. importance of HVAC Although the COVID-19 pandemic caught the world off-guard, there were plenty of historical precedents However, lockdowns during the pandemic have also tended to keep the population closed up in buildings, sometimes with less-than-adequate ventilation and access to fresh air. In retrospect, some of those decisions seem regrettable.  Although the COVID-19 pandemic caught the world off-guard, there were plenty of historical precedents. Copious research over the years supported the best approaches to stemming the spread of the virus, although it took time for historical insights to work their way into the general practice implemented in the current pandemic. There is also historical precedent for the importance of HVAC in the current pandemic. Ventilation and fresh air have become higher priorities, as has the HVAC market’s role in providing a safer indoor climate with minimal disease spread.

Change Environments Not Behaviors: How Active Air Filtration Can Help the UK Come Out of Lockdown Long-Term
Change Environments Not Behaviors: How Active Air Filtration Can Help the UK Come Out of Lockdown Long-Term

According to the latest statistics, Britain now has the highest daily COVID-19 death rate in the World, following an unfortunate record month of fatalities during January 2021. While UK Government is quick to defend this statistic, the fact remains that our country has been crippled by the SARS-CoV-2 virus, and now, as the population battles through yet another lockdown, it seems that the only 'way out’ is through widespread vaccination. impact of COVID-19 Though imperative, this strategy emphasizes the real challenge that Governments across the globe have faced in trying to control this virus; that reducing the transmission or ‘R rate’ is reliant on the behaviors of people. People who have lived with some form of restrictions for too long, people who are frustrated and tired of the impact COVID-19 has had on their businesses, and people who have simply lost trust in Government U-turns and last-minute decisions. What’s more, despite the best efforts of millions to comply with restrictions, the virus itself is one that is hard to contain, particularly with asymptomatic cases unknowingly passing it to others in key locations like supermarkets or via public transport. Regardless of this challenge, there is a solution that doesn’t rely on changing people’s behaviors, but rather in changing the environment in which people live, work and socialize. That solution is the implementation of Active Air Purification Technology. What Is Active Air Purification Technology? Active air purification technology is effective in every cubic cm of indoor air and surface space simultaneously and continuously Most air purification technologies are passive in that they can only have any effect when the air containing the pollutant comes into close proximity or passes through the unit. Examples of this are filtration, UV-C, and various PCO and ionization technologies. In other words, certain operational conditions must be met in order for them to be effective. Active air purification technology is not limited in this way and is effective in every cubic cm of indoor air and surface space simultaneously and continuously. This means pollutants, like viruses and bacteria, are instantly treated no matter where or when in the indoor space they are emitted or exposed which is significant in the context of COVID transmission. Whether required to mitigate microbials, allergens, or dangerous gases and VOCs, active technology offers a unique solution to destroying microbials instantly, offering a safer, cleaner, and more effective approach to air purification in domestic, commercial, and industrial environments. REME Air Purification Technology REME is an active air purification technology developed and patented 15 years ago by RGF Environmental Group, a COVID critical environmental innovator and manufacturer headquartered in the United States. Using no chemicals or harmful substances, REME comprises a number of known air purification technologies and sciences in one product. Its active capability works by producing and maintaining similar concentrations of hydrogen peroxide molecules as those found in the outdoor air and combines a process of bipolar ionization. When coming into contact with microbials, the naturally occurring ionized molecules break them down, destroy them and then revert them back to harmless water vapor and oxygen. The bipolar ionization effect causes other airborne particulates to agglomerate together causing them to become larger and heavier and drop out of their air or get captured in HVAC filters. RGF’s REME air purification technology produces 1 quadrillion ionized hydrogen peroxide molecules every second, quickly and safely killing any airborne virus or bacteria, including SARS-CoV-2 on a continuous basis. Its effectiveness has been verified by nationally accredited independent labs and testing bodies in the US and by other governments in numerous tests over two decades, with results also confirming a 99%+ inactivation for highly infectious viruses and bacteria, such as H1N1 or ‘Swine Flu’, SARS, Norovirus, MRSA and Bird Flu, just to name a few. Vaccinate Environments And People Air purification technology drives down the R rate for good by effectively vaccinating the air in which the virus circulates In understanding exactly how active air purification technology works and its capability to successfully destroy COVID-19, it’s clear that it presents an opportunity to drive down the R rate for good by effectively vaccinating the air in which the virus circulates. This strategy is already working its way through the United States with leading brands, like restaurant chain TGI Friday, installing active air purification technology across all establishments and has also caught the attention of renowned insurance market, Lloyds of London, which has installed the technology across all UK offices to ensure its 5,000 plus staff members can return safely to work. Improving the environment For nearly 12 months the world has been coping with COVID-19, describing it as an ‘unprecedented period’ where there is no clear end. However, in vaccinating both people and the environment in which it lives, the virus can be controlled once and for all. Ultimately, with a crippled economy, in excess of 100,000 deaths and a generation of children impacted by the closure of schools, now is the time to accelerate response and change the environments in which the virus circulates, not just the people.