Building and renovating homes in Maine’s climate is a challenge. While most customers demand that their homes be constructed and renovated to minimize heat loss - most customers don’t make similar demands for adequate ventilation. Yet ventilation of a Maine home, particularly an energy efficient home, is one of the most critical construction issues Maine builders need to address. Properly ventilated homes minimize the risk of exposure to indoor environmental pollutants (radon, carbon monoxide, carbon dioxide, combustion pollutants, chemicals) and minimize the risk of moisture damage in the building envelope and subsequent biological contamination. This program stresses why controlling ventilation in a home is necessary to protect occupant health. It will discuss the most common sources of indoor air pollution in homes and how they get there, and what physical processes are present (air flow, pressure, moisture) that affect indoor air quality. The program provides practical strategies to achieve core ventilation goals.