By The Home Ventilating Institute (HVI)
There are four basic strategies for improving air quality. First, it is important to always practice source control and separation; then a proper mechanical ventilation system should be used to reduce the pollutants. Finally, filtration can clean up remaining pollutants, that is, polish the air.
Strategy 1: Source control is simply eliminating the source of a pollutant. For instance, if you use cleaning products low in volatile organic compounds (VOCs), you won’t add those pollutants to the indoor air every time you clean the house.
Strategy 2: Practicing separation means creating a barrier between the occupied part of the house and the pollution source. If a pollutant can’t reach you, it can’t harm you. So, an airtight house can be a good way to separate pollutants such as those coming from insulation from the occupants.
Strategy 3: Ventilation is more than just air circulation between rooms—although that is a part of its purpose. With ventilation, there must be an exchange of air between the indoors and the outdoors. The best and most efficient way to exchange the air in a house is to rely on a mechanical ventilation system, which can be controlled, rather than relying on natural or accidental air pressure changes which may not occur as frequently as desired or in the areas of the house where the air changes are most needed, such as the bathroom or kitchen.
Strategy 4: Filtration is often combined with ventilation to maintain good indoor air quality. Filters capture airborne pollutants but they do not bring in fresh air, remove excess humidity, nor create oxygen; therefore, they should not be relied on as a substitute for a mechanical ventilation system
Two types of controlled ventilation systems
A high-volume local ventilation system is good for dealing with the occasional peak pollution levels or excess moisture in specific rooms. Local ventilation is desirable in bathrooms, kitchens, and other service rooms that regularly have high levels of moisture or pollution. Sometimes local ventilation is called spot ventilation because it ventilates one spot in a house.
General ventilation is referred to as whole-house ventilation because it is for every room in the house. Some people call general ventilation primary or basic ventilation because its purpose is to provide the air that occupants need on a continual basis. After all, human health is a primary consideration. A whole-house ventilation system is a relatively new term for a mechanical system that moves air through a house continuously at a relatively low flow rate. The purpose of a whole-house ventilation system is to provide a continuous air change for fresh air to maintain healthy conditions for the occupants and the building itself, not to cool the temperature of the living space. So the purpose of a whole-house ventilation system is very different from the purpose of a whole-house fan or whole-house comfort ventilator.
Consult with your builder or ventilation contractor to ensure that your house has proper mechanical ventilation. Ensure the quality of your indoor air by using ventilation products certified by the Home Ventilating Institute.
Adapted from: Understanding Ventilation: How to design, select, and install residential ventilation systems by John Bower © 2010 The Home Ventilating Institute
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