Ventilation equipment helps maintain air quality in indoor spaces. Energy- and heat-recovery ventilators help reduce utility costs by using the stale air that is being exhausted out of the space to condition the fresh air that is being brought into the space. Ventilation fans bring in fresh air or pull out stale air from indoor spaces. Blowers move high volumes of air through ductwork and are suitable for applications where high-static pressures exist. Air curtains install above entrances to keep temperature-controlled air inside and block out drafts, dust, and insects without obstructing vision or traffic through the entrances. Ducting and venting products connect to HVAC equipment to create a path for moving air through a space.