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What are occupancy sensors and how can they help building re-entry?

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Natalie Patton

Before you were confined to your house (in that bygone pre-COVID-19 era of blissful interaction with strangers and new places), you likely encountered an occupancy sensor, also called motion sensors, at least once a day. 

Occupancy sensors detect motion in an effort to indicate the presence of a person and are often used to do things like automatically turn on lights when you walk into a room or adjust temperature or ventilation settings in the HVAC system.

While we are all working hard to design a new normal that presents less opportunity for infectious disease to spread rampantly, increased use of occupancy sensors offers opportunity for building owners, from hospitals to strip malls, tenants like restaurants and retail stores, and building guests. We will outline the opportunity presented by occupancy sensors later in this post.

First, how do occupancy sensors work?

Occupancy sensors trigger automatic responses in a building system by utilizing different technologies like infrared, ultrasonic, microwave, radar or micro-vibration patterns as stand-ins for the visual representation of a body.

PIR sensors measure heat differences with a pyroelectric sensor. Since humans radiate heat, their presence is detected with these sensors as a difference in heat from a static point, like the wall the sensor is mounted on. Environmental sensors that measure temperature, humidity and CO2 can also be used as occupancy sensors, as humans cause certain changes in those environmental measures as a result of the body’s natural emission process. Occupancy sensors that rely on ultrasonic technology send high frequency sound waves (that humans can’t hear) into an area and measure reflection patterns. When the pattern changes, the sensor considers the space occupied.

Some of the newest and most promising occupancy sensors measure the vibrations, or micro movements, that are created when a person breathes and their heart pumps blood throughout their body. These occupancy sensors are successful because they offer complete privacy and security protection, they experience limited impact from external conditions and they can be deployed in a variety of open concept indoor spaces.

Using occupancy sensors in building re-entry plans

Although federal and local guidelines for re-opening the economy are still being shaped by policy makers and health officials, we can be fairly certain that social distancing is here to stay. This puts pressure on buildings and tenants to not only operate at limited capacity but prove to customers and regulators that people are in fact keeping safe distance from each other. We are expecting increased motion detection everywhere possible, too, to limit the number of surfaces that need to be touched in a given space. We’re also hearing that touch screens and interactive kiosks in public spaces may quickly be abandoned but that is a story for a different article.

For these reasons, occupancy sensors should be a key part of a building re-entry strategy. Here are a few of the opportunities we see from this technology:

No-touch control

As mentioned above, the fewer things we need to touch in a building, the better we’ll feel about going into that space. Occupancy sensors, including motion and presence detection technology, can be used to automatically turn on lights, open doors, re-set or adjust thermostats.

Code compliance

Those who own and operate large buildings are already familiar with the requirements that commercial buildings greater than 5,000 sq. ft. require automatic shut-off capabilities in certain spaces. But as we mentioned above, it is likely that regulations will be levied on smaller spaces before they are allowed to open up in the midst of this global pandemic. Though they may not be specifically required, occupancy sensors will likely help you comply with certain new laws that may be established.

People counting

As capacities will be reduced to comply with social distancing requirements, occupancy sensors can help you keep track of how many people are in your space.

Distance measuring

A step beyond people counting, some occupancy sensors can support monitoring distance between people, allowing a variety of stakeholder groups to see how far apart people are without utilizing video or compromising privacy.

Fall detection

Though not directly related to COVID-19 building re-entry, advanced occupancy sensors, like those that rely on micro-movement measurement, can identify falls by detecting how slow or fast a person reaches the ground. Those same sensors can also confirm vital signs emitted from the ground and trigger an action, like an alarm through a nurse call system in a healthcare setting.

Heart rate and breathing rate

As our understanding of the COVID-19 virus improves, the symptom list may grow to include something like elevated heart rate or increased breathing rate. If that is the case, advanced occupancy sensors can also be deployed in a building system to monitor heart rate and breathing rate and identify where there may be a body showing signs of infection.

Energy reduction

A standard benefit of most occupancy sensors is their ability to reduce waste from lights left on in unoccupied space. While some parts of re-opening your building may add cost to your building operations, occupancy sensors can be used to find some energy savings.

While occupancy sensors can do a lot to help your building re-entry strategies, these opportunities can only be realized if there are also plans to monitor the information these occupancy sensors transmit. In a different time, we may have suggested a full building control retrofit in order to realize the value of occupancy sensors. But now, we’re finding ways to deploy medium capacity controllers in combination with lightweight analytics to offer a cost-effective monitoring solution to small and mid-size buildings.

We’ve narrowed down the occupancy sensor field to the one we think does the most for the best price and coupled that with air quality sensors, a compact controller and ready-to-use analytics. Call us at (888) 684-8454, send us an email to or fill in the form found here and we will be in touch to go into more detail on the full package.

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