6 ways to measure space—and how to choose what works for you

When it comes to real estate, companies are making million-dollar decisions every day—how much space to lease, how to configure it and how to optimize operations. But many of these decisions are being made with little data on how people actually use the space.

With the rise of return to office, more companies are faced with figuring out how to design their workspaces for today’s workforce. (Check out Return-to-office playbook: 5 ways to make RTO successful) Should they double down on meeting rooms? Expand flex spaces? Shrink the number of individual desks?

Making decisions about real estate and operations based on historical precedent or gut-feel is a costly gamble. You can make better decisions if you have actual data on how your space is being used. And not just self-reported data from your employee surveys or high-level trend data from outfits like CoStar.   

This is where occupancy measurement technologies can make a big difference. They give you real-time, hard data on your space usage, helping you get more out of every square foot. (Check out More space, less waste: 6 ways occupancy sensors change the game.) 

The pros and cons of different ways to measure occupancy

Occupancy measurement comes in many forms—some highly precise, others more affordable, and a few that raise legitimate privacy concerns. Here’s a high-level overview of the six main technologies used to count people and understand space usage, along with the pros and cons of each.

1. Optical sensors (aka, cameras)

How it works:

Camera-based sensors generate low-resolution images and use AI-powered computer vision to count and track people in a space.

✅ Pros:

• Cost-effective: Can provide solid data without major infrastructure upgrades.
• Easy installation: Some models are battery-operated, eliminating the need for extensive cabling. Options that require cabling will necessitate more intall effort. 
• Medium accuracy: Because there’s a camera behind the sensor, they do a good people job—how many people and what they’re doing in a space  

❌ Cons:

• Privacy concerns: Ultimately, these are cameras. Some models capture identifiable images, then anonymize them.
• Battery life limitations: For battery-powered versions, sensors need periodic battery replacement.

Best for:

Companies that want detailed occupancy tracking but are comfortable navigating potential privacy pushback from employees.

2. Thermal and thermopile sensors

How it works:

These sensors detect heat signatures to count people and track movement.

✅ Pros:

• Low-cost and compact: One of the most affordable sensing options.
• Easy to install: Can be battery-powered, allowing for flexible placement.

❌ Cons:

• Not always anonymous: While lower resolution, some versions can detect faces or shapes of heads.
• Battery-powered sensors can be unreliable: When they go offline, it can skew data.
• Sensitivity in extreme temperatures: Thermal sensors can have trouble doing their job in very hot or cold environments

Best for:

Organizations looking for affordable, non-intrusive people counting and are okay with some limitations in accuracy and anonymity.

3. WiFi and Bluetooth Low Energy (BLE) tracking

How it works:

Instead of physical sensors, WiFi and BLE track occupancy by detecting connected devices (smartphones, laptops, watches, etc.).

✅ Pros:

• No new hardware required: Many companies already have WiFi networks that can generate occupancy data.
• Real-time, floor-level occupancy tracking: Can provide a general sense of crowd density in large spaces.

❌ Cons:

• Accuracy issues: People often have multiple devices, leading to overcounts. Plus, WiFi struggles with positional accuracy, making it difficult to determine desk and meeting room use.
• Privacy risks: Devices can be identifiable by MAC (media access control) addresses, requiring anonymization.

Best for:

Companies that want to reuse existing infrastructure to measure general occupancy but are okay with imperfect data and some privacy risk.

4. Passive infrared (PIR) sensors

How it works:

PIR sensors detect infrared light changes in a space—essentially sensing motion and body heat.

✅ Pros:

• Very affordable: One of the cheapest and easiest to install.
• Privacy-safe: PIR sensors generally don’t capture personally identifiable information (PII) although some can 

❌ Cons:

• Limited detection range: PIR sensors only detect movement within their field of view—they can’t tell if someone is sitting still.
• False positives: Can be triggered by bugs, air conditioning or random heat fluctuations.

Best for:

Budget-conscious companies that only need simple motion tracking—not detailed occupancy analytics.

5. Badge swipe systems

How it works:

Employees swipe a badge or key card at entry points to track building access.

✅ Pros:

• Simple to implement: Many companies already have badge systems in place.
• General building occupancy data: Can help estimate how many people enter a facility.

❌ Cons:

• No exit tracking: Very few companies require employees to badge out of a building, making the data only a snapshot of entrances, not actual usage.
• No real-time or space-level tracking: Can’t measure which areas people are actually using.
• Not anonymous: Badges are tied to individuals, raising privacy concerns.

Best for:

Organizations that only need entry counts and are not going after space utilization insights.

6. Radar sensors

How it works:

Radar uses radio waves to detect objects, measuring their distance, speed and movement.

✅ Pros:

• Highly accurate: Used in aviation, autonomous vehicles and weather forecasting for precision tracking.
• Anonymous at source: Radar doesn’t capture PII—no faces, no devices, no personal data.

❌ Cons:

• Target resolution limitations: May struggle to count exact numbers of people in a high-volume entrance or exit—think the end of a Taylor Swift concert.
• Complexity: Because of its high precision, some radar systems require overhead installation which can be costly.

How to choose the occupancy sensor that’s right for you 

With so many options, the right choice depends on your priorities. Here’s a quick decision guide:

✅ Privacy is critical? → Radar or Passive Infrared (PIR) sensors—These don’t capture PII.
✅ Need the most accurate data? → Radar and Optical sensors offer high precision.
✅ Looking for the most affordable option? → WiFi/BLE tracking or PIR sensors are cost-effective.
✅ Want to leverage existing infrastructure? → WiFi/BLE tracking or Badge systems require no new hardware.

Final thoughts: Some data is better than no data

If you’re making real estate and workplace decisions, relying on assumptions is risky. Even if your company isn’t ready for high-tech occupancy tracking, starting with some data is better than none.

In many cases, the cost savings from better space utilization, energy efficiency, and operational improvements will quickly pay for itself.

When it comes to occupancy sensors, the question isn’t if you should use them—it’s which one fits your needs best.