The Best Smart Motion and Presence Sensors of 2026

Buy a PIR motion sensor for hallways, lighting and alarms; choose an mmWave presence sensor when you need to detect someone sitting still, such as in a home office or bathroom. PIR sensors only react to movement and heat changes, run for a long time on a coin cell and cost little. mmWave radar picks up tiny movements such as breathing, so the lights don't switch off on you, but most need plug-in or USB power and can be fooled by fans or moving curtains.

Zigbee, Z-Wave and Thread sensors need a hub or bridge, while Wi-Fi sensors connect straight to your router. Hub-based sensors use far less power and respond faster. Common choices include brand hubs such as Philips Hue or SmartThings, Home Assistant, and Amazon Echo speakers with built-in Zigbee. Matter over Thread lets a single sensor work with Apple Home, Google Home and Alexa.

Usually, if your dog is under the sensor's rated weight limit and the sensor is mounted at the height the manufacturer specifies. Avoid aiming it at stairs, sofas or windowsills, since a cat climbing up looks like a person to the sensor. With a large dog, use the home or night mode most security systems offer, so only the door and window sensors stay armed downstairs.

Manufacturers usually quote one to two years for Zigbee or Thread sensors on a coin cell, and much less for Wi-Fi models. Busy hallways, cold garages and sensors that also report light levels every few minutes drain batteries faster. Check battery levels in your app and replace them at around 10% to 20%, so a sensor doesn't go quiet without warning.

Yes, a little: they keep lights from being left on in hallways, stairways and bathrooms, though the savings depend on your habits. For example, three 8 W LED bulbs left on an extra 4 hours a day use 96 Wh a day, about 35 kWh a year, or roughly $7 at an example rate of 20 cents per kWh (check the rate on your utility bill). Paired with smart radiator valves or smart space heaters, a presence sensor can also turn the heat down in empty rooms, which usually saves far more than lighting.