Why sensor choice matters in commercial restrooms
In high-traffic restrooms, touchless faucets improve hygiene, cut water waste, and make user flow smoother. But not all “touchless” systems work the same way. BathSelect and other manufacturers rely mainly on two sensing approaches: infrared (IR) reflectance and radio-frequency radar (microwave or mmWave). Each method detects hands differently and responds uniquely to steam, lighting, and reflective sink surfaces. The choice affects reliability, cost, and user satisfaction (BathSelect product catalog).
How the sensors work
Infrared (IR) reflectance
IR faucets emit short bursts of infrared light and measure reflections from nearby hands. When the reflected signal passes a threshold, the faucet activates. This method is affordable and widely used, but it relies on clear optics and consistent reflection patterns. Research from Silicon Labs and Vishay shows how geometry, distance, and reflectivity determine accuracy.
Performance can suffer when dirt, water droplets, or condensation cover the sensor window, scattering or blocking light (Optical Detectors Guide).
Radar (microwave / mmWave)
Radar faucets emit radio waves (commonly 24 or 60 GHz) and analyze the returned signal. Unlike IR, radar does not depend on light conditions or a visible line of sight. It works in darkness, through thin covers, and in steamy environments. Modern mmWave platforms from Texas Instruments and Infineon describe how radar measures range, motion, and even angle, giving designers more flexibility.
Radar sensors can be hidden behind non-metallic fascias, allowing sleek or vandal-resistant faucet designs (Dornbracht TOUCHFREE).
Comparing reliability in the field
IR sensors are sensitive to reflective surfaces, chrome finishes, and sink geometry. A highly polished basin can cause false triggers or missed detections. Many IR faucets now include auto-calibration to adjust the detection zone depending on sink depth and color (BathSelect features).
Radar sensors, on the other hand, are largely unaffected by glare, steam, or water droplets. Their main challenge is “over-reach,” where the sensor detects movement outside the basin if the field isn’t properly tuned. Configurable radar modules, such as Infineon’s 24 GHz sensors, allow installers to narrow the range and reduce false activations.
Hygiene outcomes
One of the biggest selling points of both IR and radar faucets is touchless hygiene. Users avoid re-contaminating their hands after washing. Some early healthcare studies raised concerns about bacterial buildup in certain electronic faucet internals, but follow-up reviews from the Association for Professionals in Infection Control (APIC) emphasized that results were brand-specific and largely preventable with proper maintenance. When installed and maintained correctly, both IR and radar systems enhance hygiene in public restrooms.
Water savings in practice
Touchless faucets are often marketed as water-saving, but studies show mixed results. The Alliance for Water Efficiency found that outcomes depend heavily on settings like run-on time and aerator choice. Poorly tuned faucets may actually increase consumption, while properly configured systems can cut usage substantially. Both IR and radar systems help eliminate “walk-away” waste, where water keeps running after the user leaves.
Installation and maintenance
IR systems
IR faucets require clear optical paths. Direct sunlight, dirt, or water spots on the sensor window can cause misfires. Regular cleaning and proper sensitivity calibration during installation help maintain reliability (Vishay design guide).
Radar systems
Radar sensors need careful range adjustment to avoid detecting movement outside the sink. Installers can take advantage of through-surface mounting, which hides the sensor behind protective panels and reduces vandalism risk (Infineon radar technology).
Cost and lifecycle considerations
Infrared remains the most affordable option, with a broad supplier base and minimal power needs (Silicon Labs IR guide). Radar is more expensive, but modern single-chip mmWave platforms have reduced cost and energy consumption, making them viable even for battery-powered faucets (Texas Instruments 60-GHz radar).
Some advanced systems combine sensors with hydro-turbine generators in the valve box, harvesting energy from water flow to extend battery life (Sloan hybrid energy faucets).
Which technology fits best?
- Infrared: Best for well-lit restrooms with standard sinks, where cost control is key and cleaning staff can easily wipe the sensor window. BathSelect’s IR range, which auto-adjusts detection zones, is suitable for most commercial deployments.
- Radar: Ideal for steam-heavy or dimly lit areas, or design-driven spaces that need hidden sensors. Premium lines like Dornbracht TOUCHFREE already demonstrate how radar unlocks new form factors and improves reliability.
Looking ahead
Emerging mmWave radar technologies are enabling finer detection zones and even gesture-based controls, potentially distinguishing between hands in the bowl and nearby movement (TI radar whitepaper). At the same time, Bluetooth-enabled commissioning apps are simplifying the setup of both IR and radar faucets, making it easier to tune range and run-on times across an entire facility (American Standard Pro app).
Conclusion
Both infrared and radar faucets offer significant hygiene and water management benefits, but they excel in different conditions. For most commercial restrooms, IR remains a cost-effective and reliable standard—especially with auto-calibration and regular cleaning. Radar, while more expensive, shines in environments where IR struggles, such as steamy or dimly lit washrooms, and opens the door to sleek, vandal-resistant designs.
Choosing the right BathSelect technology comes down to environment, design priorities, and maintenance resources. With proper commissioning and upkeep, either system can deliver the “just works” touchless experience that facilities, staff, and users all expect.
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