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What to Know Before You Choose Battery-Powered Occupancy Sensors

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battery-operated occupancy sensors

I speak with workplace leaders every day about how they’re adapting their strategies for the hybrid working world. Unsurprisingly, most of these leaders have decided to install POE or battery-operated occupancy sensors to monitor the utilization of spaces and resources. According to CBRE, 90% of enterprise organizations plan to track space utilization – a key metric to gauge portfolio performance and employee experience. Over the next three years, 80% plan to deploy occupancy sensors. 

The key drivers include plans to rightsize space to changing space needs, reduce real estate costs, and leverage space planning to create more productive and inviting workplaces. 

Whether it’s a first-time foray into occupancy sensors (having previously relied on approximations from badge data) or a poor experience with older, imprecise sensor technologies, many workplace teams are lured by the appeal of ‘peel and stick’ battery-powered occupancy sensor pilots. 

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Battery or Wired POE Sensors?

One of the most important decisions companies must make in their occupancy decision process is choosing battery-operated or POE sensors. Makers of battery sensors stress:

  • Fast Installation: The most significant advantage that battery sensors promise is getting up and running quickly. You don’t need an electrician; you just peel and stick to install the units yourself. These are very tempting attributes, especially for launching pilot tests.
  • Flexibility: Battery sensors can be installed in environments where there is no access to electricity.
  • Portability: Sensors can be moved by removing them from their current locations and reattaching them in new areas. If offices are frequently reconfigured, this can seem advantageous. 

For many companies, low installation costs and complexity are a compelling combination. But before choosing battery-powered occupancy sensors, it’s essential to consider some of the downsides. I often find myself talking with a workplace leader who has lost significant time and money on battery-powered occupancy sensor deployments that fail to meet their longer-term strategic priorities. Minutes saved in easy installation turn into weeks or months wasted ripping and replacing these systems with POE. 

In this blog, I’ll explore three critical considerations for workplace teams considering battery sensor deployment in their workplaces. 

These issues fall into three main categories: Sensor Accuracy, Sensor Maintenance, and Environmental Considerations. By understanding all of the pros and cons, you can make a better decision for your business.

Sensor Accuracy 

Companies deploy sensors to get more precise and accurate data on workplace occupancy than traditional measurement methods like surveys, entry cards, and moment-in-time observation studies. Those advantages are even more significant if your organization has a hybrid work policy with teams varying their days and times working from the office.

Battery-powered sensors promise these insights but often suffer from: 

  1. Lower detection accuracy: Battery-powered sensors typically leverage infrared, WiFi signals, or Bluetooth proximity measurement methodologies – all of which have high error rates and are less accurate for detecting the exact number and location of people in a space. High-performance radar or computer-vision battery-powered sensors are on the market but encounter issues 2 and 3, outlined below. 
  2. Low coverage range: Typically measure occupancy in a much smaller area. For example, one desk, small meeting room, or small open area ~500 sq ft versus. ~1,000+ sq ft for the highest-performance wired POE sensors.  
  3. Latency (Issues with real-time data flow):  Because battery-powered sensors must deliver a reasonable battery life before power cells need to be replaced, they often collect and batch data in 5-10 minute increments (vs. every 2 seconds for the best wire sensors.) This means they cannot collect real-time insights or properly support integrations with workplace experience/desk or room booking tools. And with fewer readings per hour, each reading is weighed more heavily in analytics, so any error rate has a larger impact on analytics.

It’s easy to see how a smaller range means more battery-powered occupancy sensors must be deployed (at a higher cost) and that low reporting frequency would limit insights available from these tools. Further, without real-time data, battery-powered sensors limit the use case for occupancy sensors to pure historical reporting. This limits the ROI and workplace experience benefits available from POE sensor investments. 

By contrast, high-performance wired or POE occupancy sensors, like those from  XY Sense, also leverage privacy-protecting computer vision but scan coverage areas every two seconds. That frequency is possible because of 24/7 wired access to a building’s electricity sources. Their real-time view of occupancy enables far greater precision in reporting space and resource utilization rates. Data from real-time electric sensors is also far more helpful as an input to space and resource booking tools.

XY Sense POE sensors offer real-time occupancy insights battery sensors cannot deliver.

A sticky proposition – is it actually quicker?

Remember, sensor deployments are only valuable if you can associate the occupancy or utilization data with associated floorplans.  Precision installation is required for that granularity, along with space mapping of the associated floor plans to indicate breakdowns of space types and team neighborhoods. 

Without careful installation, companies end up with overlapping monitoring areas, blind spots, and more false positives in people detection. Further, sensors must be installed at an optimal height for best results, so a peel-and-stick sensor may need to be attached to a threaded rod with the desired height.  Considering all this, just ‘sticking up’ battery-operated occupancy sensors can be a ‘quick way’ to waste time and money and miss out on actionable workplace insights. 

Sensor Maintenance

Upfront installation costs are often lower with battery sensors than with POE sensors. No wiring is required, and no electricians. This can feel like a powerful combination for real estate teams that just want to get started quickly and cost-effectively.

Remember, though, that with battery sensors, you will need to change batteries periodically and replace sensors as technology changes. Since battery life varies based on the individual batteries and the level of activity in the range of each sensor, be prepared to put significant resources against ongoing device maintenance. Maintenance costs will be modest if a company has only a few sensors. But these expenses increase quickly as the count of installed sensors rises. Also, like any battery-operated device manufacturer, sensor companies often quote projected battery life. Be conscious that the durations quoted are likely best-case scenarios.  

Changing Occupancy Sensor Battery

POE occupancy sensors get installed once, with no teams required to change out batteries regularly.

It’s also important to understand the process your selected vendor has for monitoring the battery life of each sensor. Is real-time monitoring available? Will you be notified one or two weeks before the battery’s end-of-life so that you can arrange for maintenance teams to replace batteries? If not, you will miss out on data as your facilities team prioritizes battery replacement with other tasks. This becomes more problematic when battery sensors are integrated with any other workplace technologies. 

Without a change battery alert system, you can lose valuable data on occupancy and resource utilization.

Additionally, the gap between battery and wired install costs is closing. Some POE companies have invested in reducing the costs, complexity, and materials needed for a wired installation. My company XY Sense leads in this area. We pioneered an installation methodology called Senselink, which enables us to daisy chain sensors instead of relying on hub-and-spoke deployments, which speeds installation while reducing wiring and other equipment costs.

With Senselink, sensors can be wired in chains to one another instead of connecting each device individually to a hub like the spokes of a wagon wheel. 

XY Sense Senselink installation uses a daisy chain to dramatically reduce wiring and other installation needs.

With Senselink, clients get: 

  • Shortened installation time because cables only run short distances to the hub and don’t need to extend back to a PoE switch
  • Omission of PoE switches, which are currently in short supply and can take up to a year to order
  • Reduction in cabling congestion for a faster installation with fewer opportunities for confusion and cabling errors
  • Ability to utilize shorter, pre-fitted cables, which cost far less than continuous rolls of ethernet cable
  • Use of our exclusive XY Hub technology, which eliminates the need for POE switch equipment 
  • Exclusive use of low-voltage equipment, which eliminates the need for high-cost, high-voltage electricians to complete the install
  • Dramatically reduced metal and plastic demands to enhance sustainability. This is in addition to battery-free sensors, which don’t contain power cells containing heavy metals

Those savings add up. For example, we helped a global financial services company save $12M across its APAC-wide, many-facility installation with Senselink

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Environmental Considerations

The rise of hybrid work rules has prompted many companies to revisit their workplace footprints to drive significant reductions in carbon output. Many companies are deploying occupancy sensors to reduce environmental impacts as part of their ESG commitments. Better workspace utilization and rightsizing can drive massive reductions in carbon emissions. In the US alone, commercial buildings generate 826 million metric tons of carbon dioxide emissions (16 percent of all U.S. carbon dioxide emissions.)

All sensors can help companies identify ways to improve their carbon impact. The more accurate the data, the better the decisions it enables. Whether you choose battery or POE, you can better understand current space and resource utilization levels so you’re not creating unnecessary carbon by delivering services to empty areas.

But with the insights from a real-time POE sensor system, companies can make more accurate predictions about space and resource demands and adjust their operations accordingly. For example, a company with low occupancy levels on certain days of the week can change the number of “open” floors and reduce heating, cooling, and other costs in unused areas. We’ve worked with several companies that have identified cost and carbon savings of 30-40% by rightsizing alone. 

Where POE or wired and battery sensors differ dramatically is in the amount and types of toxic e-waste they generate. Electric sensors require wiring but access energy from more efficient sources once installed. Battery sensor deployments require more devices and generate significant amounts of toxic battery e-waste. 

Batteries contain one or more of cadmium, lead, zinc, manganese, nickel, silver, mercury, and lithium. A battery can leach its toxic constituents and contaminate groundwater and land when disposed of in an unlined landfill. 

The larger your deployment, the bigger the environmental challenge.

With large battery sensor installations, the quantity of e-waste can be considerable. 

For a 20,000-headcount organization, a battery-powered system could mean as much as 1-2,000 pounds of waste battery waste every two years. Rechargeable batteries reduce the total quantity of e-waste, but their toxic constituents are often more dangerous than conventional batteries. 

Some electric sensor companies have worked to minimize the need for wiring and other components to grow their ecological advantages over battery sensors further. For example, XY Sense has pioneered Senselink, an installation methodology that leverages daisy chaining to reduce wiring needs by up to 80% over traditional hub-and-spoke installation. 

Conclusion

At XY Sense, we focus solely on POE sensors because they are more accurate, easier to maintain, and more environmentally friendly. We did that with the full knowledge that some companies will choose battery-operated occupancy sensors because initial installation costs and complexity can be lower. Every company must make choices based on both immediate and long-term needs. 

In our view, those seeming advantages are far outweighed by the greater accuracy, lower maintenance costs, and superior ecological profile of electric sensors over time. 

If you’re considering a sensor deployment in the next 12 months, I’d urge you to consider both your immediate and longer-term needs. What are you hoping to get out of a temporary battery-powered deployment? Is it worth investing a few more weeks at the front end of a project to save from a vicious cycle of ongoing battery maintenance and wiring rework at the back end?  

If you’d like to discuss battery versus POE sensors or any other aspects of occupancy sensors and analytics, please contact us or request a demo. We can discuss your specific immediate needs and what may be valuable for you in the future so that you can make the best decision for your business.

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