Shelly Presence Gen4 Review: $84.99 Price, Features and Limits

A smart light that switches off while someone is still reading in bed is not much of a smart light. Shelly’s Presence Gen4, now available in the United States for $84.99, is designed to address that familiar problem by detecting people who remain still, rather than waiting for movement. It also divides a room into configurable detection zones, allowing different areas to trigger different automations. The hardware is promising, but its advertised capabilities need a closer look: Shelly’s product page promotes tracking up to 10 people, while its detailed technical specifications list detection of up to six.

Why Shelly’s Presence Gen4 is different from a motion sensor

Traditional motion sensors generally react when someone moves through their detection area. That works well for hallways and entrances, but it can be unreliable in a bedroom, home office or living room where someone may sit quietly for an extended period. Shelly Presence Gen4 uses millimeter-wave (mmWave) radar, which detects small movements and can identify a person who is sitting still within its stated detection range. The practical difference is that an automation can keep a room occupied while someone reads, works at a desk or watches television without repeatedly waving an arm to reactivate the lights.

This does not mean the sensor can identify a person's identity or understand what they are doing. Its job is to detect presence and position within the monitored space, then make that information available to compatible automation systems. That distinction matters when comparing it with a camera: the Presence Gen4 can support occupancy-based actions without capturing video, but it is not a replacement for visual identification or a conventional security camera.

Ten detection zones could make room-by-room automation more precise

The Presence Gen4 supports up to 10 configurable detection zones, letting users divide a larger area into sections rather than treating the entire room as one occupied-or-empty signal. For example, a home office could have separate zones for a desk and a reading chair, while an open-plan living area could distinguish a seating corner from a walkway. Each zone can then become a separate input for automation, subject to the capabilities of the connected platform and the configuration required there. This approach is more useful than a basic motion sensor when the goal is to control lighting or other devices according to where someone is, not merely whether anyone is somewhere in the room.

Zone detection does require setup, however. Users need to position the sensor, configure the monitored areas and test how it behaves in the actual room. Furniture, mounting angle and the distance between the sensor and a seated person can affect the result, so a manufacturer’s maximum coverage figure should not be treated as a guarantee that every corner will detect still presence equally well. The most useful setup is one tested around the places people actually sit, work or sleep.

The advertised people count needs a closer look

Shelly’s US product listing says the sensor can track up to 10 people simultaneously, and its headline feature description repeats that figure. Yet the detailed technical specification on the same product page lists radar object detection for up to six people. Those are different published limits, and the available documentation does not clearly reconcile them. Buyers should therefore avoid assuming that the device will reliably distinguish 10 occupants in every room or configuration until Shelly clarifies the discrepancy.

The distinction may not matter much in a small household using the sensor to automate a single office or bedroom. It matters more in shared rooms, busy workspaces or commercial environments where several people may occupy different zones at once. In those cases, the actual number of simultaneously tracked people is more consequential than the headline figure because it can affect how confidently an automation interprets occupancy. The sensor’s multi-zone design is a useful feature, but the people-tracking claim deserves verification before it becomes a purchasing requirement.

What the $84.99 price buys, and what it does not

Shelly lists the Presence Gen4 at $84.99 in the United States, positioning it above simpler motion sensors that only report movement or a general occupancy state. The extra cost buys radar-based still-presence detection, configurable zones, a built-in ambient-light sensor and several connectivity options. It also supports direct device configuration through an embedded web interface, which may appeal to people who prefer to manage smart-home equipment without relying entirely on a mobile app. These capabilities are most valuable when a household will actually use zone-level automation rather than simply switch a light on whenever someone enters.

The sensor needs continuous power through USB-C, so it is not a battery-powered device that can be placed anywhere without planning for a cable. An independent product review reports that the package includes a USB cable but not a power adapter, meaning buyers may need to provide a suitable adapter separately. Shelly recommends a dedicated, stable 5-volt power supply and warns against chargers whose output fluctuates when other devices are connected or disconnected. That is a small additional setup consideration, but it can affect where the sensor can be installed and how tidy a wall-mounted installation looks.

Connectivity is flexible, but compatibility still matters

The Presence Gen4 supports Wi-Fi, Bluetooth and Zigbee, along with Matter-over-Wi-Fi compatibility. Matter is a smart-home interoperability standard intended to help devices from different manufacturers work together through compatible controllers. The sensor also integrates with Shelly’s own ecosystem and Home Assistant, while Shelly documents occupancy-related integrations for Google Home, Amazon Alexa and Samsung SmartThings. That range gives buyers several ways to incorporate the device, but it does not mean every platform exposes every radar feature in the same way.

Zone support is particularly worth checking before purchase. Shelly documents up to 10 configurable zones, but the way those zones appear in a smart-home interface depends on the integration. Its knowledge base explains that Matter-compatible systems may show one room zone by default, with additional zones needing to be added separately. A buyer planning detailed room-level automations should confirm that their chosen controller exposes the information they need, rather than assuming that Matter certification automatically delivers identical controls across every app.

Camera-free sensing improves privacy, not every kind of security

Because the Presence Gen4 uses radar rather than a camera, it can monitor occupancy without recording images of people in the room. That is a practical advantage for bedrooms, bathrooms, offices and other spaces where a camera would feel intrusive. Shelly also provides local device configuration and offers a cloud-free local-control option, which can appeal to users who want their automations to operate without depending on a cloud service. Still, camera-free does not mean risk-free: the sensor communicates over a network, and its privacy characteristics depend partly on how it is configured and which connected services receive its data.

It is also important not to treat presence detection as proof that a property is secure. A sensor that reports an occupied zone can help trigger lighting or an alert, but it does not provide visual evidence, identify a specific person or guarantee that every occupant will be detected. For security-sensitive use, it should be one part of a broader setup rather than a standalone substitute for appropriate door sensors, alarms or cameras where those are justified.

Detection range is not the same as reliable still-presence range

Shelly specifies a 140-degree horizontal field of view for wall mounting and describes coverage for rooms up to approximately 8 by 8 metres, depending on placement. However, its technical documentation gives a still-detection distance of up to three metres. Those figures describe different aspects of operation: a sensor may monitor a broad area for movement without reliably maintaining a still-presence reading at the far edge. An independent review also highlights the shorter still-presence range as a limitation, making placement near a desk, bed or sofa more sensible than relying on the maximum room dimensions alone.

Mounting height and angle affect the area the radar can observe. Shelly recommends an installation height of about two metres and an approximate 15-degree tilt, while also documenting different mounting configurations. Before fixing the unit permanently, test the detection where people are likely to remain still and check whether nearby movement, pets or a robot vacuum produces unwanted triggers. Adjustable sensitivity and filtering options can help, but they do not remove the need to tune the sensor for the room.

Who should consider the Shelly Presence Gen4?

The Presence Gen4 is a stronger fit for smart-home owners who want lights, climate controls or other devices to respond to actual occupancy, including when people sit still. Its configurable zones are particularly appealing for open-plan spaces, home offices and rooms where one sensor needs to support several distinct automations. Buyers who already use Home Assistant or another compatible controller may find the flexible connectivity more valuable than someone who only wants a simple hallway light trigger. The $84.99 price is easier to justify when still-presence detection and zone-specific actions solve a problem that a cheaper motion sensor cannot.

It is a less obvious choice if the only requirement is to detect someone walking into a room, if a power cable would be difficult to hide, or if dependable still-presence detection is needed at distances beyond the documented three-metre range. The conflicting published people-count figures are another reason to verify requirements before deploying several units in a busy environment. For a single room, the sensible next step is to map the intended zones, confirm compatibility with the chosen smart-home platform and test the sensor's placement before building automations around it.