There's a strong body of research on how building health, efficiency and controls positively impact worker productivity in offices. However, much of that research is from a few years ago, when a variety of recently released technologies were not yet available to monitor indoor spaces. The researchers had to depend on surveys and tests of building occupants rather than actual measured data about the indoor spaces. 

But the market for indoor occupancy tracking is rapidly maturing. Over the past few years, a variety of companies have launched products that can track what's happening inside a space: This includes people counting, movement analysis, and occupancy detection on a per-seat basis. 

In addition to a number of startups emerging in this industry, some building incumbents are starting to make acquisitions. Enlighted, which was recently acquired by Siemens, has embedded passive infrared sensors into its LED lights, to monitor indoor movement. Another recent Siemens acquisition, Comfy, has moved beyond its core HVAC control capability to provide occupants with more control over their space. Convene, which operates conference space and workspace as a service not unlike WeWork, acquired Beco, which makes technology to monitor indoor space usage and provides a development kit to other app developers.  

One of the first steps to optimizing space, operational systems, and improving productivity is deploying sensors that collect real-time data. These sensors continuously monitor conditions, occupancy and other key indoor characteristics in real time. By compiling a data-driven view of how a space is used, it is possible to make appreciable improvements. Moreover, indoor sensing enables a variety of other value propositions in modern office space, such as HVAC optimization. 

However, the sensor space is very confusing. There are a variety of technologies currently available, and the differences are not always apparent. The data collected by these sensors is only part of the solution, but it does impact the value that can be provided within an indoor environment. For example, some sensors only collect certain kinds of data, or at certain levels of granularity, which limits their potential for a number of office use cases.

Below is a summary of the key technology types currently found in the market.

(For a deep dive on the state of building energy management in 2018, check out my three-part series for GTM Squared.)

Lighting-integrated motion sensors

These sensors are most commonly used to control lights by detecting movement. In some states, they are required by building codes. While there are different form factors, this type of sensor is always packaged with a lighting system and used to control it. The key value proposition is that the sensors reduce lighting energy consumption by automatically turning off lights when a space is unoccupied.

However, these sensors may not be capable of supporting a broad range of smart office needs. For example, these sensors typically track general occupancy: Is the room empty or not? They are unable to provide a count of individuals in a space. Finally, many buildings may want to invest in indoor occupancy sensors but not new lights, especially if they already have LEDs.

Standalone motion sensors 

This is an emerging technology that typically uses passive infrared sensors mounted across an indoor environment. They have become popular in recent years because they can be installed without any construction or occupant disruption. They also consume small amounts of energy and can be battery-operated, which reduces ongoing maintenance and total cost of ownership.

Office heat maps, which show general patterns on occupancy, plus hot spots of high utilization, typically use these motion sensors. This technology does have some deficiencies for smart building and productivity use cases. First, each desk or discrete workspace requires its own motion sensor, which can add to the initial cost for deployment. Plus, the sensors just track motion, but not counts. While more employees in a space may lead to more movement overall, the lack of precise counts makes it difficult to understand true utilization within a space.

For example, commercial real estate giant CBRE notes that there is a conference room imbalance between average meeting size (a significant number of meetings comprise just two to three participants) and occupant space (many meeting rooms can hold six to eight occupants). These sensors may not provide enough data to solve this issue. At the same time, some offices may find that the data that they do gain from standalone motion sensors will give them enough information to improve their space. Enlighted is one example of a company that uses these sensors, integrated within lights, to deliver indoor occupancy tracking. 

Badge scanning sensors

Many offices give their employees badges that employ radio frequency identification (RFID) or other technology for access control and security requirements. An employee touches her badge to a receiver near a door in order to gain entry. This proven technology is effective for simple access-control needs, but often is insufficient for more detailed data collection and monitoring.

For example, some employees follow colleagues into a space without using their own badge (known as “tailgating”). In other cases, employees use their badge to enter a space, but not to exit. This provides some data on arrivals, but no visibility on when the office space begins to clear out at the end of the day. What's more, once an employee is within the secured area, badges provide no data on actual position. The data from access control systems may lead a building manager to invest in a more detailed indoor monitoring solution, but on its own, it won’t provide very much value. 

Bluetooth sensors and beacons

Bluetooth, more specifically the low-energy variant, is the technology behind beacons, which are most commonly used in retail environments to push promotions to shoppers based on location. This technology will continue to proliferate in shopping environments, but it has some deficiencies in offices.

For example, Bluetooth requires each user to have an app open for it to track location. This works well when a shopper is looking for a specific part of a store or is reviewing a promotion, but is not effective in passive monitoring use cases within an office. Moreover, the requirement to install an app leads to lower penetration rates than seen with other technologies. 


Wi-Fi likely has the highest penetration of any sensor technologies on this list because most buildings already have Wi-Fi to provide internet connectivity. Wi-Fi also can be used to track individual devices that are connected to a network, which can provide some indoor occupancy data. Wi-Fi is available in most office environments and can provide general occupancy counts (e.g., how many people came to work today). But it has a number of shortcomings as an indoor occupancy tracking technology.

First, the technology isn’t proven for indoor location uses, and data quality is generally poor. For example, it can be difficult to know if a particular device is on the third or fourth floor of a building. To provide more detailed space data, a building would need to provide dense Wi-Fi access points, more dense that what would be necessary simply to provide internet connectivity. Second, employees with two mobile phones, or a phone and a tablet, may be double counted. Finally, some device manufacturers randomize the unique address that the device uses to connect to a network (a process called MAC address randomization). This makes it difficult to track individual devices over time, which is vital to understanding how a space is used and occupied.

In short, knowing the number of people in a space is useful, but knowing ongoing trends — are people in the office everyday, every other day, or only one day a week — is more important. Moreover, in Europe, the General Data Protection Regulation limits the storage of personally identifiable data, like the unique ID of a device.

Furniture-integrated sensors

These sensors can be useful to track direct utilization of desks. For large hotel offices, they may be suitable. Such sensors can track if a desk is occupied over time and provide summary reports on overall utilization. But this sensor type also presents a similar challenge as lighting-integrated sensors: The need for new office furniture may not coincide with an interest in deploying indoor sensors for space utilization purposes.

Even sensors that can be added to existing furniture will miss what is happening away from desks: informal meetings by a kitchen or in the hall, or within an office lounge. Many of the emerging office concepts are moving away from large spaces of cubicles, to open areas with various types of workstations.

Door-counting sensors 

These sensors track movement through a doorway. The most common use case is to track occupancy in conference rooms, which typically are used inconsistently and have a single entry and exit point. In some cases, data quality can be challenging. Errors can accumulate over time due to the occupied/unoccupied state that is registered, and auditing these records can be challenging. Additionally, many offices are open concept and do not have many doors.

This technology has value for conference room tracking, but may not be as useful for other office applications.

Video-based sensors

There are two core types of sensors in this bucket. The first uses existing security cameras and analyzes the images to count people or provide other indoor sensing capabilities. This technology piggybacks on existing deployments of cameras and is very accurate. However, this technology can be costly to deploy and operate over time. Additionally, most security cameras are found at entrances, exits and elevators, but not in every conference room. The result is that the data collected and analyzed covers only a portion of the indoor space. Adding new cameras to other areas requires significant hardware installation and wiring; a costly endeavor that is distracting to office workers.

The second type of video sensor is a self-enclosed form factor that includes a camera, connectivity and even a battery for power. These sensors typically are easy to deploy. Some have long battery life and are wireless to avoid cabling costs and hassles. The key benefit is that in concept, software can be written to identify various objects that are within the view of the camera. This is not unlike how Amazon operates its “Go” convenience stores.

These sensors are not as common as the other technologies, but do have some advantages. At the same time, due to video capture, this type of sensor may be unwelcome in organizations that want to protect worker and occupant privacy. Some vendors process the images on the sensor hardware, but do not transmit them to any other system — this may satisfy some privacy concerns. 

The capabilities of each of these technologies will undoubtedly change over time. The market is too nascent to make any reliable predictions on which technologies will dominate the smart offices of tomorrow. But all of these technologies work well and have been deployed in offices. Any building owner or operator looking at indoor occupancy sensors could consider any of these technologies as realistic options. Moreover, the use cases for such indoor space sensing are growing and maturing, which will drive technology innovation.

Read our three-part series on the state of building energy management: