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Homeowners can go with flow to solve air problems; Good ventilation, insulation are a plus

Orlando Sentinel

There is a widely held misconception about energy efficiency that says plugging leaks and cutting down on airflow into and out of a house will cause indoor air-pollution problems.

Although energy efficiency urges a "tight house" with minimal air infiltration, the thinking sometimes goes that cutting down on airflow increases health problems inside the building.

Energy experts argue strongly that this theory is off base, noting that uncontrolled airflow brings outside moisture, pollutants and other unwanted air problems into the home.

Keeping the house tight allows airflow to be controlled, introducing outdoor air from known sources and pre-treating it to control moisture and outdoor pollutants. Some savvy builders are now calling this technique "build tight and ventilate right."

One study of this technique, by the Canada Mortgage and Housing Corp., was based on a questionnaire study of 15,000 homes in 30 communities in Canada in the early 1990s.

The study looked at the correlation between occupant-reported respiratory disease symptoms and indoor moisture and mold problems.

The researchers followed up with field testing in more than 400 houses, taking short-term air samples indoors and out, air-dust samples from the living room and bedrooms, swabs from visibly moldy areas and dust from a child's bedding.

They also looked at the air exchange rate of the houses, ran a condensation-prediction model and used a cough-recording system to measure coughing by a child in the home.

As the researchers noted, their studies "debunked" a number of preconceptions about homes and airflow. They found that leaky houses did not have less mold than tight ones. Tighter houses with lower air-exchange rates did not have higher relative humidities, higher levels of condensation or higher levels of biological contamination. And contrary to what some expected, leaky houses had higher, rather than lower, measures of biological contamination.

That '70s style

They also noted that a disproportionate number of the highly contaminated houses were built in the 1970s; a disproportionate number of the low-exposure homes were built since 1986 (since there has been more emphasis on tightening homes).

This study provided evidence refuting concerns that energy-efficient homes had indoor air problems.

The right way to solve indoor air problems, says Subrato Chandra, a project director at the Florida Solar Energy Center, is to seal the house tightly to make it energy efficient and stop uncontrolled airflow that brings in moisture, dirt and pollen from the outdoors. Then you need to ventilate, filter and, in some climates, dehumidify the house to get good indoor air quality.

Chandra played a key role in the design of the American Lung Association's Health Houses in Orlando, Fla., and several other U.S. cities, basing his suggestions on this strategy. He adds that a good job of vacuum cleaning in the house can keep dust mites at bay and resolve more health issues.

Good ventilation is important in every house. There are so many potential sources of air pollution inside the typical house that it becomes essential to keep a home well-ventilated. Examples of pollution sources are damp carpets, deteriorated insulation, household cleaning products, personal-care products and building materials.

Whether your home is energy-efficient and well-sealed or leaky and drafty, pollutants can build up inside, causing discomfort and health problems.

Passing the smell test

To check your indoor environment, the Environmental Protection Agency suggests that you go outside for a few minutes and see whether you notice any odors when you walk back in.

Other signs of poor ventilation include moisture condensation on walls and windows, dirty heating and air-conditioning equipment and mold on books, shoes and other items.

Certainly the first step in keeping your house healthy is to get as many potential pollutants outside as possible. Don't store pesticides, chlorine bleach and cleaners in the home. Minimize the use of aerosol spray products. Get any insulation problems fixed. Make sure gas stoves and gas and oil furnaces are properly adjusted and maintained. Even indoor smoking builds up strong pollutants. Minimize the burning of candles, too.

Opening up

The next step is to increase ventilation into and out of your home. When the weather allows you to open windows and doors or use fans, do so.

If you're building a new home or remodeling, talk to your contractor about installing a mechanical ventilation system that will bring outdoor air into the home. You can also consider buying a home air cleaner.

We like to think of our home as a refuge from the world around us, a place where we can go to be safe. Protecting the air inside the home is an important part of making it the secure place we want it to be, so "build tight and ventilate right."

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Ken Sheinkopf is associate director for the Florida Solar Energy Center in Cocoa, Fla. For more information on energy efficiency and renewable energy, visit the center's Web site at http://www.fsec.ucf.edu/.