Good indoor air quality is essential for a healthy and productive workplace. Studies show that most indoor spaces contain at least 5 times the pollutants found outdoors. In general, mechanical ventilation systems remove pollutants (including mold-producing moisture) at their sources. In a predominantly cold climate like Vermont, we recommend an exhaust-only or balanced system to prevent moisture-laden air from gathering in building cavities with cold, condensing surfaces.

For smaller areas (less than 1500 sq. ft.), electrically efficient bath fans designed for extended run periods on a 24-hour timer can provide some ventilation at minimal cost. This type of system works best with a tight shell and structural means to facilitate air flow (i.e. undercut doors, transfer grilles). It's most appropriate for new, small buildings with sealed combustion appliances. More involved ventilation systems incorporate ductwork for distribution. This ductwork must be sealed and insulated where necessary. These systems remove or supply air from an arrangement of points. Simple exhaust-only systems use an electrically efficient fan and ductwork to pull air out of multiple rooms or areas.

For larger buildings, heat recovery ventilation systems, also known as air-to-air heat exchangers, make sense. While the volume of air being exchanged and cost of the fuel can vary, the distribution is effective. Return air is pulled from areas with pollutant sources (bathrooms, kitchens) and fresh, preconditioned air is exchanged. This requires ductwork that is effectively sealed and insulated where necessary. Consult a knowledgeable contractor if you're planning to integrate an heat recovery system with a forced-air heating and/or cooling system.