Investing in Occupancy Sensors? 3 Considerations Before You Buy

Liz Voeller
February 14, 2019

 As we discussed in parts one and two of our series on occupancy sensors, there’s a lot for buyers to consider when trying to make an informed purchase. Our clients often come to us bewildered by the options, asking, “how do I sort through the various sensor technologies and know which ones are best for my business?” Having dug into the world of occupancy sensors as part of our Works with Comfy program and our efforts to optimize our own workplace experience here at Comfy HQ, our team knows their way around the market. Our team of expert solution designers typically works with customers to define and prioritize their use cases and get a better sense of what types of sensor technologies match their needs. But what else do you need to consider in your sensor selection? We break it down here.

We typically advise customers to first consider what existing systems they can leverage. Sometimes, an existing building system—like a connected lighting system—can provide sufficient occupancy data to meet your desired use case. The trade-off is that while you may not get the specific type of data you want (i.e. people count), you are able to use this occupancy data with no additional investment. Similarly, it is important to assess whether you are planning to deploy sensors during a new office renovation or significant retrofit, or while the building is in use. Where you are in the project lifecycle can both create new opportunities or present limitations. For instance, as part of a retrofit you might choose to install a system as Power over Ethernet (PoE) instead of battery, which has implications for latency and operating costs depending on the technology (more on that later).

Three key trade-offs to consider

In working with our customers, we’ve found that the best way to identify a sensor vendor that will meet your specific needs is to first understand how you and your organization evaluate three key things: data granularity and frequency, total cost of ownership (TCO), and privacy. Let’s dig into the key considerations for each.

Data granularity and frequency

When evaluating a sensor solution, you’ll need to consider the data specificity that is required for your scenario. Given your desired use case, access to a specific data type—such as people count, “gross” utilization (e.g. low, medium, high use), and yes/no occupancy—will influence your sensor selection. For example, wanting to know the number of people in the cafeteria to estimate live wait times or plan future cleaning schedules requires a sensor with advanced people counting capability and the ability to communicate in real time. The configuration of your system also impacts the useability of your data; choosing a wired vs. battery-powered system can impact performance (see table below).

Total cost of ownership

When evaluating sensors, it is critical to weigh both upfront costs and costs of ongoing maintenance. A holistic assessment should include costs for hardware, installation labor, replacement parts (like batteries), and maintenance labor, and decision criteria should recognize the trade-offs between these costs and different sensor types. For example, while some of our customers prefer the flexibility and ease of deployment that battery-powered sensors provide, others are wary of the accompanying maintenance costs.

Privacy concerns

We cannot ignore today’s privacy concerns when it comes to sensors in the workplace. Some sensor types, like imaging sensors, spark greater concern than others based on their means of collecting data. While images are typically processed on the sensor itself and not stored or shared, this type of technology can be met with pushback in some enterprise organizations. Check with your desired sensor vendor to review their privacy policy and practices and if they meet common standards like GDPR.

Key Trade-offs when Evaluating Occupancy Sensors
 Vibration sensorsPIR sensorsImaging sensors
Offers occupied/unoccupied data in distinct locations like soft seating.Offers occupied/unoccupied data in discrete locations like rooms or under desks; some sensor vendors can provide gross utilization rates at a room or neighborhood level.Offers people count and occupied/unoccupied data in open or discrete locations like in open areas, over desks, or in rooms.
Data granularity and frequencyKey trade-off: granularity of data vs. impacts to flexibility and cost
Is there someone in the seat?

 

🔌N/A

🔋Limited use cases; can serve niche uses like furniture utilization.

Is there someone in the space?

 

🔌 Wired sensors enable increased data frequency but limit flexibility in mounting locations and form factor; may be best installed at retrofit depending on need.

🔋Battery configuration offers added flexibility in mounting locations; has minimal impact to data granularity/ frequency of occupancy data.

How many people are in the space? Is there someone in a specific area?

 

🔌 Wired sensors enable increased data frequency but limit flexibility in mounting locations; may be best installed at retrofit depending on need.

🔋On-sensor image processing impacts battery life; battery configuration can limit real-time nature of data.

Total cost of ownership (TOC)Key trade-off: upfront/maintenance costs vs. impact to flexibility
🔌 N/A

 

🔋Reduced upfront cost per sensor, but incurs maintenance costs due to battery replacement and tracking of mobile furniture.

🔌 Typically requires upfront install labor cost from a contractor or similar, but avoids maintenance costs associated with batteries; may be best installed at retrofit.

 

🔋Typically low upfront install costs but should factor in maintenance costs for battery replacement; offers added flexibility in mounting locations.

★ Make sure to check if you can leverage your existing connected lighting system for useable data.

🔌  Typically requires upfront install labor cost from a contractor or similar, but avoids maintenance costs associated with batteries; may be best installed at retrofit.

 

🔋Must factor in maintenance costs for battery replacement; may still require contractor for install given particular mounting arrangements.

★ Tends to come at a price premium on a per sensor level. However, given your desired use case, may require fewer sensor units in total, thereby reducing operational costs.

PrivacyKey trade-off: sensor type vs. perceived privacy concerns
Relatively few privacy concerns.Relatively few privacy concerns.Can spark greater privacy concerns. Check with your desired sensor vendor to review their privacy practices.

🔌=Wired configuration (e.g. PoE, wall outlet)

🔋=Battery configuration

Finally, a note about real-time data

The ultimate value that occupancy sensors can bring your organization, immediately and in the long-term, is actionable data. Unlike historical utilization trends, real-time data allows you to put sensor feedback to immediate use, through employee-facing tools that provide a better overall employee experience and more automated space optimization. This data can also help you get insightful utilization trends to inform strategic space planning.

To make sure you’re purchasing a system that can deliver real-time occupancy data, you’ll need to make sure your intended sensor system is configured to do so. Make sure to ask sensor providers—how often do your sensors push data to your server? If your organization requires an on-prem server instead of the cloud, confirm that the sensor provider can meet that requirement and at what impacts to service. Good questions to ask include: “do data push frequencies change?” or “is battery-life reduced in this scenario?”, and “does beaconing capability become limited when installed in this way?”

We’re excited about the evolving world of occupancy sensors and the value that they deliver to real estate teams looking to make more informed decisions about space and workplace utilization. But we also get that the market can be difficult to navigate. Comfy’s team of experts is on call to help you understand the trade-offs and considerations as they relate to your desired outcomes and workplace needs. Reach out to us today. to discuss your workplace goals.


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