According to a laboratory study involving the removal efficiency of influenza A, more than 99 percent of the influenza was removed by the whole-house product from Trane, CleanEffects.

Consumer interest in influenza may never have been higher than it is this year. People are getting flu shots in record numbers, and providers are frequently running out. According to several news sources, media reporting on H1N1 has led to an increased awareness of flu in general.

At companies that offer flu shots to employees, the number of those taking advantage of this perk are higher than in previous years. Nurses administering those on-site vaccinations confirmed that shortages of seasonal flu vaccines have frequently been reported by suppliers. The demand has been outpacing the supply.

In short, people are interested in flu prevention. It’s a good time for contractors to use their knowledge of IAQ equipment to help ease customer peace of mind, and protect them against flu and other types of respiratory illness. (Keep in mind, though, that IAQ products have not been confirmed to protect specifically against H1N1.)

Environmental Health & Engineering (EH&E) is a company that studies environmental and public health issues. According to a laboratory study involving the removal efficiency of influenza A, more than 99 percent of the influenza was removed by the whole-house product from Trane CleanEffects. “In practical terms, this means that when the airborne virus enters the HVAC system with room air, more than 99 percent of the influenza that passes into the high-efficiency air cleaner is retained and not distributed through the house with the supply air,” said Dr. David MacIntosh, principal scientist with EH&E and an adjunct associate professor of Environmental Health at the Harvard School of Public Health.

To understand what more than 99 percent removal efficiency would mean for exposure and health risks, Dr. MacIntosh and his colleagues put results from the laboratory into a widely accepted mathematical model of IAQ in homes. Dr. MacIntosh described the model as a way to understand airflow both within a home, and from outdoors to indoors.

They modeled three separate scenarios of influenza emissions and movement within a home:

1.A sick child in a bedroom with an adult caregiver.

2.Two children, one infected with flu and one not, in separate bedrooms.

3.A person who is contagious for five days and spends one-half of their time in the bedroom and one-half of their time in the family room.

“If you think about airflow in a house with forced air conditioning, air in the home is drawn to the HVAC system and recirculated to the rest of the house,” he said. “We asked, what is the change in the risk of infection via airborne transmission for various types of in-duct and portable aerosol filtration systems?” Compared to conventional filtration, the whole-house, in-duct air cleaning system reduced the risk of infection 15 fold over a five-day infectious period, the study said.

“Compared to two HEPA portable cleaners (one in the bedroom, one in the living room), we found a ten-fold reduction in the risk of infection.”

One of the messages of the study, according to the senior author Dr. MacIntosh, “is that in addition to providing comfort to customers, contractors can provide better IAQ in terms of biological and chemical contaminants. From my perspective as a public health practitioner, it would be valuable for HVAC contractors to learn about the health benefits of filtration. They can actually become valuable conveyors of public health information.”

With higher-efficiency filtration, Dr. MacIntosh said, people with high-efficiency air cleaners “are expected to have lower risks of acute respiratory outcomes, like worsening of existing asthma, and long-term problems like cardiovascular illness.”

Additional research by the company was recently published in a scientific paper titled “Control of Asthma Triggers in Indoor Air with Air Cleaners: a Modeling Analysis.” The study compared the performance of various air-cleaning products to the implications of actual exposure, specifically the relation to health - in short, how the product’s performance affects levels of illness or infection among occupants. It combines the results of lab and in-home studies, and a mathematical model that estimates exposure to fine particulate matter and viruses (like rhinovirus) in indoor air from simulations of air movement within the home, and the flow rate and removal efficiency of an air cleaning product.

“We studied the effect of removing particles from indoor air on potential exposure and health risks,” said Dr. MacIntosh, and compared it to portable air cleaners and standard HVAC system filters, which are only intended to protect the components of an HVAC system. EH&E also examined the removal of micro-organisms from the air, mold spores, bacteria, and viruses.

The study concluded that “forced-air systems with high-efficiency filtration were found to provide the best control of asthma triggers: 30-55 percent lower cat allergen levels, 90-99 percent lower risk of respiratory infection through the inhalation route of exposure, 90-98 percent lower environmental tobacco smoke levels, and 50-75 percent lower fungal spore levels than the other ventilation/filtration systems considered. These results indicate that the use of high efficiency in-duct air cleaners provide an effective means of controlling allergen levels not only in a single room, like a portable air cleaner, but the whole house.”

In conclusion, “These findings are useful for evaluating potential benefits of high-efficiency in-duct filtration systems for controlling exposure to asthma triggers indoors and for the design of trials of environmental interventions intended to evaluate their utility in practice.”

The study compared natural ventilation with no air cleaner; a conventional 1-inch media filter; a 5-inch MERV-8 media filter; a high-efficiency, whole-house air cleaning system (the Trane CleanEffects product); and a portable room HEPA air cleaner.

The Trane CleanEffects whole-house air cleaning system.


Beth Stevens, product manager, Packaged Products & Indoor Air Quality for Trane Residential Solutions, said that when dealer-contractors come through the manufacturer’s Tyler facility, they are encouraged to bring up topics of interest. “One of the biggest topics we’ve heard this year has been flu, which has been very top of mind with their customers,” said Stevens.

“As IAQ becomes more important to them, they contact their contractors and ask what they have to offer.

“I’ll give credit to our contractors as well as our team here,” she continued. “We’re really focused on selling systems and meeting customers’ needs. We think it’s really important to offer a product that solves their IAQ problems as well. We have a great base of contractors who offer that with every sale.”

While price is always a concern, it’s not the bottom line for these contractors and their customers, she said. “We feel that they go in with the mindset of driving down to the customers’ needs, instead of saying, ‘What price are you looking for?’ ”

The CleanEffects product has been made specifically for the manufacturer’s systems. “It’s part of a complete heating or cooling system, either existing or new,” Stevens said.

Contractors need to keep in mind that it doesn’t take an entirely new system installation to sell an add-on product like a whole-house air cleaner of any brand. “A lot of times a contractor will go in to repair a system or even do a clean and check, and they will take the opportunity to talk to the customer about improvements they might make in their home,” said Stevens.

Customer testimonials were solicited shortly after the California wildfires in San Diego County, she added. For customers in the area who were evacuated from their homes, their air cleaners were hosed out; the units were totally black, she said, but the homes had no smell compared to their neighbors’. “I have a system in my home,” she said. “I got the product installed in January. I’ve noticed a tremendous reduction in our allergies and dust. In our home it was very obvious.”

For more information, visit or

Publication date:12/28/2009