About the Author
Mr. Harrington is a general contractor with 35 years' experience who provides expert consulting services to attorneys, property owners and other contractors.
In the early 1980s, California began regulating energy conservation in buildings through Title 24 of its Code of Regulations. Among other things, Title 24 strictly regulates the design of windows and other building openings. The laudable goal was to reduce energy lost by heating and cooling drafty buildings, but there have been unintended consequences. While requiring homes to be air-tight makes sense from an energy-saving perspective, people’s failure to remember that fresh air circulation is necessary to maintain indoor air quality has contributed to undesirable health hazards.
People often believe that if a little is good, more is better. They think the tighter they seal-up their home and the longer they keep things buttoned-up the more energy they will conserve. Perhaps, but what’s lost in this equation is the need to regularly exchange indoor air to keep it healthy. While this is obvious with cigarette smoke it’s no less true for air particles we can’t so easily detect.
In most California dwellings interior air is refreshed with exterior air through what is termed "natural ventilation,” the process by which we ventilate a space though passive movement of air through openings to the outdoors. Obvious enough, but what’s important to understand is that the amount of required natural ventilation has been reduced by law. The ICC model codes (adopted by the California Building Codes since their 2007 edition) have reduced the required ventilation by 20%. Section 1203.4.1 has reduced the required ventilation from 5% of the floor area of a room to 4% of the floor area, and has removed the minimum requirement altogether.
That same set of rules has subtly stipulated that the responsibility for providing natural ventilation belongs to building occupants by adding language that states, "The operating mechanism for such openings shall be provided with ready access so that the openings are readily controllable by the building occupants."
It is important to remember that our homes need light and air to be healthy. With that in mind the need for energy conservation is a distant second. In other words, it’s up to us to open our windows now and then.
One of the most common negative consequences arising from the failure to properly ventilate a dwelling is the buildup of excessive moisture. A family’s day-to-day activities pump gallons of water vapor into a home’s air. Cooking, showering, even our breathing moistens indoor air. And the process is cumulative. Without the introduction of fresh outdoor air, each day adds water vapor. Eventually the air becomes saturated and moisture starts to condense on the surfaces inside the home. This leads to accelerated fungal growth, including those of mold and mildew – and a host of resulting health issues.
In the past, most dwellings ventilated themselves, but not today. With today's energy conservation techniques, a building occupants have to be much more proactive – and accept their share of responsibility for maintaining their home’s indoor air quality.