Ventilation equipment maintains indoor air quality through the intake of fresh air and exhausting of stale air. Ventilation fans move air between indoor and outdoor spaces. Blowers and air movers push high volumes of air through ductwork and are suitable for high static pressure applications. Draft inducers and combustion air systems balance airflow within a combustion system. Energy- and heat-recovery ventilators help reduce utility costs by using exhaust air to condition the fresh air being brought into the space. Air curtains install above entrances to keep conditioned air inside and block out drafts, dust, and insects without obstructing vision or foot traffic. Duct and venting products connect to HVAC equipment to create a path for moving air through a space. Dampers and louvers provide control over airflow into and out of occupied spaces.