Indoor Air Quality Control and Ventilation

By Paul Bianchina
It's certainly no secret that we spend a lot of our time indoors. In fact, the American Lung Association estimates that the average American spends almost 90 percent of their time indoors, about half of which is at home. And while that air we're breathing in the house is something we pretty much take for granted, is it as clean and as safe as we'd really like?

Source Control

There are any number of sources for contaminates in your house. The first step toward good indoor air quality is to identify as many as you can, and then take steps to eliminate or reduce them right at the source.

Does anyone in the house smoke? Secondhand smoke is an irritant and a considerable health hazard, and the best way to deal with it - short of quitting - is to not allow smoking inside the house.

Are gas appliances properly vented? Check to make sure that all gas appliances are vented to the outdoors in an approved manner, and that all components of the vent system are solid, undamaged, and properly connected.

Are insecticides or pesticides used indoors? These products can have serious health effects when used in confined areas. Avoid or restrict their use indoors, carefully follow the manufacturer's instructions for adequate ventilation, and store the containers outside your living space.

Do you have furry pets indoors? The best way to deal with the dogs and cats in our lives is to vacuum frequently to reduce pet hair buildups, and change furnace filters regularly.

Do you work on hobbies indoors such as woodworking, jewelry making, pottery or model building? Consider the use of an exhaust fan system to suck out dust and fumes as you work, keep all containers tightly capped when not in use, and don't work with any chemicals indoors if you cannot provide the correct amount of ventilation as recommended by the manufacturer.

Do you store a lot of cleaners and chemicals inside? Here again, keep containers tightly closed, and consider storing more of your cleaning supplies in the garage or a storage shed between uses.

Ventilation

As you might expect, indoor air quality is more of an issue during the winter than it is during the summer, for the simple reason that our homes are more tightly closed up and the amount of fresh, outdoor air entering the house is substantially reduced. In conjunction with that, builders have been constructing homes considerably tighter in recent years to improve owner comfort and reduce utility bills. Better windows, tighter-fitting doors, improved use of caulks and sealants, air barriers under siding - it all adds up to a better-built house but less fresh air.

Since we don't want to construct a drafty house or throw the windows open on a bitter winter day, the only option is to improve on your home's ventilation system. This is a combination of bringing fresh air in and exhausting stale, potentially contaminated air to the outside.

One way is to operate kitchen and bathroom exhaust fans periodically. The fans push indoor air to the outside - make sure they're not just vented up into the attic! - which removes the stale air and also creates a small amount of negative pressure in the room. Air will always move from higher to lower pressure, so as the pressure in the room is lowered, air from outside will make it's way in to take its place. This is obviously not the most efficient or well-regulated method of ventilation - how well it works is dependant on how powerful and well-placed the exhaust fans are, how much volume of air there is in the house, and how many gaps and cracks are open to the outside to allow air to enter. There are also the disadvantages of exhausting heated air, using electricity to power the fans, and bringing in dust and other potential pollutants from outside.

A simple and inexpensive alternative is to use non-powered continuous ventilation ports. These are small vents that are placed on the outside walls of the house in various locations to allow a small, continuous amount of fresh air to enter the building - louvers and filters prevent dust and rain from entering through the outside openings. These use no electricity, require no maintenance, and, properly placed, create a fairly efficient and controlled ventilation system. There are also vinyl windows available that have small, adjustable ports above one of the sashes, allowing a very small amount of air to enter the house without the security problems of leaving a window cracked.

For even more efficiency and control - but with a higher price tag - consider an air-to-air heat exchanger. These units bring in outside air while exhausting inside air, and the two air streams pass one another to allow heat from the inside air to be given off to the colder, incoming air from outside. Less heat is lost, the amount of airflow can be carefully regulated, and the units are large enough to ventilate the entire home.

For more air quality tips and sources for ventilation products, contact your utility company.

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