No doubt about it, we all want houses that are energy efficient, affordable, comfortable, and healthy. Yet, many houses feel stuffy due to lingering odors and too much humidity; condensation on windows leads to mold growth and decay; and many of us suffer health effects due to polluted indoor air. All these issues interact in a variety of ways, and ventilation is a major piece of the puzzle.
There are two primary reasons for ventilating houses: 1) to provide the necessary fresh air for the occupants to breathe, and 2) to dilute indoor air pollutants and excess moisture. Complaints of stuffiness, unpleasant odors, and illness are common in houses that contain too little fresh air. Outdoor air pollution is bad enough, but we are now learning that indoor air pollution is almost always considerably worse—and this polluted air can make us sick.
To feel comfortable and healthy, people simply need clean air. While breathing is something few of us consciously think about, each of us breathes every minute of every hour of every day of every year of our lives. We breathe primarily to take the oxygen into our bodies that we need to survive, but we also exhale moisture, carbon dioxide (CO2) and a variety of other by-products of metabolism. We take air in, we use it, then we expel it, and even though we do this unconsciously most of the time, our bodies are specially designed to provide this service to us continuously.
But, don’t houses breathe also? Yes, but in many cases they don’t do it very well. A ventilation system should be as reliable and predictable as our own lungs. Houses without ventilation systems get their air quite by chance—the air moving into and out of them is totally uncontrolled. For example, air may infiltrate indoors only when the wind is blowing. We deserve to have control over the air we breathe, we deserve more than “ventilation-by-chance,” we deserve “ventilation-on-purpose.”
When air enters a leaky house through the cracks, it may contain radon or other pollutants, and thus, not be very clean or healthy. We deserve a ventilation system designed to bring in clean air. We deserve a system as efficient as our lungs. Our automobiles typically have better ventilation systems than our houses. Even though some houses get enough fresh air by chance some of the time, research is showing us that most newer houses simply don’t have enough fresh air on a regular basis.
What about the fact that most houses have never had ventilation systems? Why do we need them now? Part of the answer lies in the fact that we expect more out of our houses than our grandparents did. We aren’t willing to accept drafty, uncomfortable, unhealthy, energy-wasting houses. At the same time, considering all of the various synthetic materials and cleaning products we bring indoors, our houses have more and different sources of indoor pollution today. We spend more of our time indoors than our parents or grandparents did, and we generate more indoor moisture with steaming-hot showers, washing machines, dishwashers, and hot tubs. Today’s houses are also more energy-efficient, are more tightly constructed, and have smaller furnaces—all of which lead to less “natural” ventilation.
Why not just build looser houses? People really don’t want to live in loose houses—they are drafty, uncomfortable, and consume too much energy. We can’t afford to waste energy heating and cooling our houses any more than we can continue to waste it in gas-guzzling automobiles. And, just because a house is loosely constructed doesn’t mean the occupants are getting enough fresh air—loose houses can be unhealthy, too.
What about air filters? Filters are one of several ways of improving the air quality in houses. But filters can’t supply us with oxygen and they can’t remove moisture from the air. So, if you use an air filter in your house, you still need ventilation—although you might not need quite as much. As it turns out, all the different strategies for reducing air pollution should be used in addition to ventilation, not instead of it.
