U.S. Department of Energy - Energy Efficiency and Renewable Energy

Federal Energy Management Program

New and Underutilized Technology: HVAC Occupancy Sensors

The following information outlines key deployment considerations for HVAC occupancy sensors within the Federal sector.

Benefits

HVAC occupancy sensors detect when people are in spaces. When no one is in the room, controls reduce the thermostat set point in the winter and raise it in the summer.

Application

HVAC occupancy sensors are applicable in house, service, office, research and development, school, hospital, and prison applications.

Key Factors for Deployment

A carbon dioxide (CO2) or occupancy sensor is linked to the HVAC system. The technology is best for spaces with variable occupancy that cannot be predicted solely by time. Occupancy sensors provide quicker control response than CO2 sensors and are less costly.

Occupancy sensors may cause excessively rapid cycling if located in a space where occupants enter and exit frequently. CO2 sensors can allow controls to adjust the number of people in a space if a variable air volume system is used.

If the interior space of a building has internal heat loads such that it is cooling even when cold outside, raising the thermostat temperature would be a misapplication of this control technology.

Ranking Criteria

Federal energy savings, cost-effectiveness, and probability of success are ranked 0-5 with 0 representing the lowest ranking and 5 representing the highest ranking. The weighted score is ranked 0-100 with 0 representing the lowest ranking and 100 representing the highest ranking.

Federal Energy Savings Cost Effectiveness Probability of Success Weighted Score
0.6 5.0 3.8 51