actual number of people within the building at any given time is
frequently lower than the designed peak occupancy. If the building
has a conventional HVAC system that delivers a fixed rate of
outside air pegged to the peak occupancy, the result can be
overventilation and a waste of energy and money.
A cost-effective solution in many situations is carbon
dioxide-based demand controlled ventilation (DCV). This
well-established technology uses one more carbon dioxide (CO²)
sensors and a system controller to vary minimum outdoor air
ventilation based on indoor CO² levels. Since humans exhale carbon
dioxide at predictable rates depending on how physically active
they are, indoor CO² levels can serve as a proxy for
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