HRV devices reduce respiratory symptoms in children: Study

Apr 7 2010

Houses today are so well sealed that they can trap humidity and pollutants indoors as a result of insufficient ventilation. Recently, a team of Canadian scientists led by Dr. Tom Kovesi, a pediatric respirologist at the Children's Hospital of Eastern Ontario in Ottawa, Canada, performed a randomized double-blind, placebo controlled trial to determine whether use of heat recovery ventilators (HRV) would increase home ventilation and therefore reduce the risk of lower respiratory tract illness in young children. The team's verdict? Use of HRVs was associated with an improvement in air quality and reductions in reported respiratory symptoms in children.

The study represents one of the most important conclusions made to this day on indoor air quality in single family dwellings. It was performed in the polar region of Qikiqtaaluk, Nunavut, which has the highest reported rate of hospitalization for a severe respiratory viral infection in infants in the world. Many of these infants need to be flown to Children's hospitals in Ottawa for treatment and serious long-term pulmonary complications may follow these infections. In collaboration with the local Nunavut Housing Corporation, researchers studied homes in 4 communities. After a search for HRVs capable of performing under extreme cold (-40 C), and appropriate consents were granted, housing units were retrofitted with Constructo(TM) 1.0 HRV units made by Venmar Ventilation. About half of the HRV units were modified to appear to supply outside air but were only recirculating air. This allowed a comparison between more versus less ventilation. During the study period, scientists recorded ventilation levels, CO2 concentration, temperature, humidity and visits to the community health center for respiratory illnesses in children.

Results

Dr. Kovesi's study concluded that improving ventilation through the use of HRV devices was associated with an improvement in indoor air quality and significantly reduced the incidence of important respiratory symptoms in young Inuit children. "Many elements got our attention," says Dr Kovesi. "First, the mean indoor CO2 level in homes with active HRVs was 33% lower than in homes with placebo ventilators (disconnected). Indoor CO2 concentration is important as it reflects home ventilation, and our previous research has shown that increased indoor CO2 (or reduced ventilation) is associated with higher risk of lower respiratory tract infections in children. Rates of reported wheezing and rhinitis were significantly lower in the active HRV group". Dr Kovesi also points out that "the HRVs also significantly reduced relative humidity. Houses in the arctic are dry, and the intervention tended to make the air inside even drier".

For Pascal Ialenti, President of Venmar, the team's findings in Ottawa and Nunavut confirm what his own team believed for a long time. "Our own experience taught us that an HRV is an efficient device to reduce CO2 and pollutants in indoor air. Dr. Kovesi's work stresses for the first time, to our knowledge, that a relationship actually exists between use of HRVs in homes and a reduction in the incidence of respiratory disease symptoms in young children. The team's efforts give a new meaning to anecdotal reports to Venmar from parents whose children suffer from respiratory problems and who installed an HRV to provide them with a healthier home environment".

Best Choice for Cost/Efficiency Ratio

Don Fugler, Senior Researcher at Canada Mortgage and Housing Corporation, was a member of Dr. Kovesi's team in Nunavut. In an article published in Building Better - a First Nations National Building Officers Association publication - he makes these recommendations to house builders and inspectors as well: "Well-ventilated houses have healthier residents and less deterioration due to moisture damage. It is worth the effort ... For new houses, the least costly system to operate is a fully-ducted heat recovery ventilator (HRV). HRVs should exhaust continuously from bathrooms, kitchen, and basement, and supply air to the bedrooms and living areas".

Discover How You Can Make a Difference for Your Child

Healthy air is a crucial factor when it comes to the comfort of children with respiratory conditions. Visit www.healthyairstudy.com to learn how HRVs work and how they can contribute to make your home a cleaner, safer and healthier place for your loved ones. Find how people just like you made the healthy air choice.