What is the difference between a motion sensor and a presence sensor?

A motion sensor uses passive infrared and only triggers on movement. A presence sensor uses 60GHz mmWave radar to detect breathing and micro-movement, so it reports a room as occupied even when nobody moves.

Which presence sensor should I buy in 2026?

The Aqara FP400 for Matter, local control and occupancy counting with fall detection. The Aqara FP2 is the cheaper option with 30 configurable zones.

Are water leak sensors worth it?

Yes. A Govee H5054 costs about 20 dollars, sounds a 100dB local alarm and pushes a phone notification the moment it detects moisture.

Smart Home Sensors: The 2026 Directory

Smart home sensors are what turn a collection of connected gadgets into automation that actually works. The single biggest change in 2026 is mmWave radar presence sensing, which detects a still human being rather than a moving one, and finally solves the oldest complaint in the hobby: lights switching off while you sit reading. This directory covers presence, water leak and life safety sensors worth putting in a home.

What is a smart home sensor?

Sensors are the input side of home automation. Motion sensors use passive infrared and only fire when something warm moves, which is cheap and fast but blind to a person sitting still. mmWave presence sensors use 60GHz radar to detect breathing and micro-movement, so they know a room is occupied even when nobody moves, and the better ones map a room into zones and count people. Alongside presence, the sensors most worth owning are water leak detectors, which prevent the single most expensive category of home damage, and smart smoke and CO alarms. Sensors complement rather than replace smart security cameras, since a radar sensor sees occupancy without recording anyone.

Buying guide

Buy presence sensing for rooms where people sit still: offices, living rooms, bathrooms. The Aqara FP400 is the pick if you want Matter and Zigbee with local control, since it reports occupancy count, position and posture including fall detection with no camera involved. The FP2 is the earlier and cheaper model with up to 30 configurable zones and five-person tracking.

For water, a Govee H5054 under a dishwasher or water heater costs 20 dollars and will pay for itself the first time it fires, with a 100dB onboard alarm plus phone alerts. For life safety, the First Alert Onelink Safe and Sound is a UL-listed smoke and CO alarm that doubles as an Alexa speaker, which makes it easier to justify in a hallway. Note that local control matters more for sensors than for almost anything else, because a sensor that depends on the cloud adds latency to every automation it triggers — which is why the best smart home hub for Matter matters here, and why presence sensors pair so well with smart thermostats that can heat only occupied rooms.