Thermostat + Co2 Sensor in single device tied to BMS

you might find an IR measurement device that has a temperature sensor so that the CO2 measurment electronics are temperature compensated. Then trying to get that value is an other issue. Just put in a CO2 detector.

I have to ask, why does a LEED place need CO2 measurements?

More and more these days, in an effort to reduce the energy needed to pre heat or pre cool fresh ventilation air being introduced in to buildings, direct control of how much air that has to be brought in is being implemented.

Rather than just have a constant fixed amount of outside air, whether the building requires it or not, control strategies are being implemented to reduce the introduction of outside air when it is not needed and increase the amount when needed.

This does have an impact on energy use as in the case where I live in the summer outside air is 100+ degrees F and in the winter could go into single digits.

If I can directly control the amount of outside air necessary to ventilate the building I can match energy use to energy need.

Using CO2 as a measurement of how much OA is needed gives us a way of reducing the energy use when the requiremnets are low and still allowing the appropriate amount of fresh ventilation air to keep the air quality in the bulding high.

Do you still need CO2,T,RH sensor all in one????