Air-mixing plenum

The process may include filtering, heating, cooling, humidification, or dehumidification, all of which consume energy.

Enhanced controls systems may monitor the return air quality or carbon dioxide concentration[3] in order to automatically modulate the air mix for optimum energy efficiency while maintaining desired fresh air requirements.

Such systems work very well in buildings where the occupancy rate can vary greatly throughout the day, or seasonally.

In such conditions the mixing damper will be set to close and the system use full fresh air for optimum energy efficiency.

Where fresh air is not required, such as early morning pre-heat or pre-conditioning periods, the mixing damper can be automatically set to full recirculation, again for optimum energy efficiency.