Saving Energy Nationwide in Structures with Occupancy Recognition

SENSOR program graphic

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Program Description:

The projects of ARPA-E’s SENSOR (Saving Energy Nationwide in Structures with Occupancy Recognition) program will develop user-transparent sensor systems that accurately quantify human presence to dramatically reduce energy use in commercial and residential buildings. SENSOR projects will focus on one or more of four areas: 1) human occupancy sensors for residential use, 2) occupant-counting sensors for commercial buildings, 3) CO2 sensors to enable the use of variable building ventilation based on data from occupant-counting sensors, and 4) real-world testing and energy savings validation of these technologies. Projects in the SENSOR program seek to reduce energy used by heating, ventilation, and air conditioning (HVAC) systems by 30% in both residential and commercial buildings, potentially producing savings of 2-4 quadrillion BTU (quads) across the U.S. power system. SENSOR projects will develop sensing technologies that minimize or eliminate the need for human intervention while pursuing aggressive cost, performance, privacy, and usability requirements in order to gain the acceptance and penetration levels needed to achieve this 30% reduction in HVAC energy consumption.

Innovation Need:

About 13% of all energy produced in the United States today is used to heat, cool, and ventilate buildings. Furthermore, 37% of all energy used by commercial buildings goes toward HVAC—even greater for residences, at 40%. Much of this energy is wasted, being used when buildings are unoccupied or occupied well below the maximum levels for which they are designed.

Simple major motion sensing is popular as a means to control lighting to save energy (although with significant failure rates when occupants are not moving). To function properly and save energy, sensor systems that inform temperature controls must meet much more stringent requirements than those used for lighting systems; to control ventilation, a true occupant count must be used. To address this challenge, it is necessary to employ entirely new technologies and algorithms that accurately determine occupant presence and number while simultaneously protecting privacy. By offering high accuracy and thus quantifying the precise need for temperature control or ventilation, SENSOR projects will make it possible to keep occupants comfortable without the faults presented by a similar system using basic major motion sensing. Optimized ventilation, only possible with occupant counting, will be able to dramatically reduce energy use without the risk of poor indoor air quality or unwelcome changes in temperature, which affect occupant comfort, productivity, and potentially health. These savings will be achieved while occupants go about their day, without interacting with (or even noticing) the systems whatsoever.

Potential Impact:

If successful, SENSOR projects will dramatically reduce the amount of energy needed to effectively heat, cool, and ventilate buildings without sacrificing occupant comfort or privacy.


Lower electricity consumption by buildings eases strain on the grid, helping to improve resilience and reduce demand during peak hours, when the threat of blackouts is greatest.


Using significantly less energy could help reduce emissions attributed to power generation. In addition, improved interior air quality could help prevent negative effects on human health.


Buildings will require less energy to operate, reducing heating, cooling, and ventilation costs for businesses and families. In addition, improved indoor air quality (ensured by an accurate occupant count, and validated via widespread CO2 detection) may lead to improved worker productivity and academic performance.


Program Director:
Dr. Marina Sofos;Dr. Olga Spahn
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