Since the beginning of last year new residences and additions > 1000 square feet have been required to meet mechanical ventilation requirements. This became necessary as buildings are built tighter and external factors such as noise cause homeowners to keep doors and windows shut. This requirement is most commonly met with local exhaust fans. The quantity of air required is derived from a formula based on the building size and number of bedrooms found on the Installation Certificate. Local exhaust fans can be assumed to operate continuously if they have a sone rating of 1.0 or less and have a statement (see example below) located at each control point indicating the importance of ventilation to maintain indoor air quality.

Example Statement- "To maintain minmum levels of outdoor air ventilation required for good health,the fan control should be on at all times the building is occupied, unless there is severe outdoor air contamination."

The Installation Certificate (CF-6R-MECH-05) should be completed and available for final inspection. You can find a link to a copy of the Installation Certificate in the Resources section of our website. Of course, when conditions are right natural ventilation can be the choice of the occupant with this approach.