Saving Energy with CO2 Monitoring

Have you heard of Sick Building Syndrome?  ​The sick building syndrome (SBS) is used to describe a situation in which the occupants of a building experience acute health- or comfort-related effects that seem to be linked directly to the time spent in the building. No specific illness or cause can be identified.

One of the main ways to combat SBS is to bring in adequate outside air.  The codes require that a certain amount of outside air is brought into the building based upon the number of occupants.  The reason for this is that each occupant breaths out CO2, and high levels of CO2 are thought to be one contributing factor to SBS.

A great deal of energy is required to heat or cool this outdoor air that is brought into the building.  So from an energy standpoint you want to bring in as little outside air as possible. As you can see this is a conflict with the SBS.  In a perfect world your building would have just enough outside air to keep the occupants healthy, but no more.

Many buildings today are over ventilated, which means that way to much outside air is entering the building than is needed for the occupants.  One way to prevent this is to use sensors to monitor the level of CO2 and then only ventilate when the CO2 levels are above recommended levels.
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For example, a cafeteria in a school is a great example of a room that is empty much of the day, and a full capacity during the lunch period.  During lunch the fully required amount of outside air is needed based upon the number of people present in the room.  For many hours of the day, while this room is mostly empty, a very minimal amount of outside air is required.  Much energy can be saved by reducing the ventilation to a minimal level during these hours.