Category guide
Best local leak, contact, and environmental sensors
Comparison tables are useful, but most buyers still want a plainspoken shortlist. The matching guide gives that recommendation layer.
Read the buying guide →Compare category
Environmental and contact sensors comparisons
Leak, contact, and environmental sensors worth installing in a local-first home.
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Browse environmental and contact sensors
Want the full set of product notes with images, outbound product links, and buyer caveats? Jump back to the catalog for this category.
Browse product notes →Strongest overall pick
AirGradient One
AirGradient · HA: excellent · local: excellent
true NDIR CO2 sensor alongside PM2.5, temperature, and humidity, not just VOC estimation
View product notes →Best local-control posture
AirGradient One
AirGradient · works offline: yes
Open-source hardware running ESPHome firmware. Fully local, no cloud account required. Can be flashed with custom firmware for complete control.
Why it stands out →Easiest starting point
AirGradient One
AirGradient · setup: easy
Home Assistant users who want accurate, local indoor air quality data with CO2 readings
See buyer notes →| Criteria | AirGradient One | AirGradient Open Air | Apollo AIR-1 Air Quality Sensor | Apollo PLT-1 Plant Sensor | Aqara Climate Sensor W100 | Aqara Door and Window Sensor P2 | Aqara Motion and Light Sensor P2 | Aqara TVOC Air Quality Monitor | Eve Door & Window | Eve Motion | Eve Room | Eve Weather | Heiman Smart Carbon Monoxide Alarm | Heiman Water Leak Sensor | HomeWizard P1 Meter | Shelly BLU Door/Window | Shelly BLU Motion | Shelly H&T Gen3 | Shelly Plus PM Mini Gen3 | SONOFF SNZB-02D | SONOFF SNZB-03P | SONOFF SNZB-04P | SONOFF SNZB-06P Zigbee Occupancy Sensor | SwitchBot Contact Sensor | SwitchBot Leak Detector | SwitchBot Meter Pro CO2 | Third Reality Water Leak Sensor | ThirdReality Door Sensor | ThirdReality Garage Door Tilt Sensor | ThirdReality Motion Sensor (Matter) | ThirdReality Motion Sensor R1 | ThirdReality Smart Soil Moisture Sensor | ThirdReality Temperature and Humidity Sensor | ThirdReality Temperature Sensor Lite | ThirdReality Vibration Sensor | ThirdReality Zigbee Water Leak Sensor | Zooz ZSE11 Q Sensor | Zooz ZSE18 Motion Sensor | Zooz ZSE42 Water Leak XS Sensor | Zooz ZSE43 Tilt/Shock XS Sensor | Zooz ZSE44 Temp/Humidity XS Sensor |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Local control | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | good | good | excellent | excellent | excellent | excellent | excellent | excellent | good | good | good | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent | excellent |
| Cloud dependency | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none | medium | medium | medium | none | none | none | none | none | none | none | none | none | none | none | none | none | none | none |
| Home Assistant fit | excellent | excellent | excellent | excellent | good | good | good | good | good | good | good | good | good | good | excellent | good | good | excellent | excellent | excellent | excellent | excellent | good | good | good | good | good | good | good | good | good | good | good | good | good | good | excellent | excellent | excellent | excellent | excellent |
| Works offline | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| Setup difficulty | easy | moderate | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | moderate | easy | easy | easy | moderate | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy | easy |
| Needs extra hub / controller | no | no | no | no | no | yes | no | yes | no | no | yes | no | no | no | no | yes | yes | no | no | yes | yes | yes | yes | no | no | no | yes | yes | yes | no | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes | yes |
| Power / form factor | usb | usb | usb | usb | battery | battery | battery | USB-powered | battery | battery | battery | battery | battery | battery | usb | battery | battery | battery | hardwired | battery | battery | battery | USB-powered | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery | battery |
| Protocols | wifi | wifi | wifi, esp-home | wifi, esp-home | matter, thread | zigbee | matter, thread | zigbee | matter, thread | matter, thread | thread, matter, bluetooth | matter, thread | matter, thread | matter, thread | wifi | bluetooth | bluetooth | wifi, mqtt, bluetooth | wifi, mqtt, bluetooth | zigbee | zigbee | zigbee | zigbee | bluetooth, matter | bluetooth, matter | bluetooth, matter | zigbee | zigbee | zigbee | matter, wifi | zigbee | zigbee | zigbee | zigbee | zigbee | zigbee | z-wave | z-wave | z-wave | z-wave | z-wave |
| Best for | Home Assistant users who want accurate, local indoor air quality data with CO2 readings | Home Assistant users in areas affected by wildfire smoke or urban air pollution | Home Assistant users who want comprehensive indoor air quality data for health-conscious automations | Home Assistant users who want to automate plant watering based on actual soil moisture data | Home Assistant users who want cheap, local climate sensors for every room | Zigbee-based Home Assistant setups needing reliable door/window sensors | Thread-based Home Assistant setups that want simple, reliable motion triggers | monitoring indoor air quality trends alongside temperature and humidity | privacy-conscious buyers who want a no-cloud contact sensor | privacy-conscious buyers who want a no-cloud motion sensor for indoor or sheltered outdoor use | privacy-conscious users who want indoor air quality monitoring with zero cloud involvement | Home Assistant users who want local outdoor climate data for automations | users who want a cross-platform smart CO alarm with local-only operation | budget-conscious users who want Matter leak sensors deployed in multiple locations | Dutch and Belgian homeowners who want real-time energy data in Home Assistant | Home Assistant users with a Shelly BLU gateway who want cheap, reliable door and window sensors | Home Assistant users building motion-activated lighting or presence-based automations on a budget | Home Assistant users who want a standalone temperature and humidity sensor with a readable display | Home Assistant users who want per-circuit energy monitoring without adding switching capability | Home Assistant users wanting cheap, reliable temp/humidity monitoring | Home Assistant users building motion-activated lighting automations on a budget | Home Assistant users who want to monitor every door and window cheaply | budget presence detection for lights-on-when-occupied automations | SwitchBot ecosystem users who want affordable door and window sensors | placing under sinks, near water heaters, and in basements for early leak detection | indoor air quality monitoring with Home Assistant automations | budget water leak monitoring under sinks, water heaters, and washing machines | blanketing your home with door and window sensors on a budget | knowing whether your garage door is open or closed from within Home Assistant | Home Assistant users who want Matter-native motion sensing without a Zigbee coordinator | budget motion-activated lighting automations | automating garden watering based on actual soil conditions | room-by-room climate monitoring in a Zigbee Home Assistant setup | deploying cheap temperature sensors in every room for whole-home climate tracking | detecting when the washer or dryer finishes running | scattering cheap leak detectors under sinks, water heaters, and washing machines | rooms where you want motion-activated lighting plus environmental monitoring in one device | hallway or closet light automation where you just need motion detection | under sinks, water heaters, washing machines, and anywhere pipes can leak | garage door open/close monitoring without wired sensors | monitoring temperature and humidity in wine cellars, server rooms, crawl spaces, or greenhouses |
mid price band
AirGradient One
AirGradient · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Open-source indoor air quality monitor with true NDIR CO2 sensing and ESPHome compatibility.
premium price band
AirGradient Open Air
AirGradient · local control: excellent · cloud: none
- Setup: moderate
- Needs extra hub: no / self-contained
- Standout: Open-source outdoor air quality monitor with PM particulate tracking and ESPHome integration.
mid price band
Apollo AIR-1 Air Quality Sensor
Apollo Automation · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: All-in-one air quality sensor covering PM2.5, VOC, CO2, temperature, and humidity, fully local via ESPHome.
budget price band
Apollo PLT-1 Plant Sensor
Apollo Automation · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Budget ESPHome plant sensor measuring soil moisture, soil temperature, and ambient light, fully local.
budget price band
Aqara Climate Sensor W100
Aqara · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Budget Thread-native temperature and humidity sensor with full local control.
budget price band
Aqara Door and Window Sensor P2
Aqara · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Long-battery contact sensing with optional Matter integration paths for broader ecosystem flexibility.
mid price band
Aqara Motion and Light Sensor P2
Aqara · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Thread-native motion and light sensor with no hub requirement and full local control.
mid price band
Aqara TVOC Air Quality Monitor
Aqara · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Three-in-one TVOC, temperature, and humidity sensor with an always-on e-ink display.
mid price band
Eve Door & Window
Eve · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Privacy-first Thread contact sensor with zero cloud dependency.
mid price band
Eve Motion
Eve · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Privacy-first Thread motion sensor with IPX3 weather resistance for indoor and sheltered outdoor use.
premium price band
Eve Room
Eve · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: A fully local indoor air quality monitor with an e-ink display, no cloud account, and zero data collection by the vendor.
mid price band
Eve Weather
Eve · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Outdoor-rated Thread weather sensor with temperature, humidity, and barometric pressure, all fully local.
mid price band
Heiman Smart Carbon Monoxide Alarm
Heiman · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Among the first Matter over Thread carbon monoxide alarms available, with cross-platform smart home support.
budget price band
Heiman Water Leak Sensor
Heiman · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Affordable Matter over Thread water leak sensor with cross-platform compatibility.
mid price band
HomeWizard P1 Meter
HomeWizard · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Reads real-time energy data from Dutch/Belgian P1 smart meters with a fully local API.
budget price band
Shelly BLU Door/Window
Shelly · local control: good · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Ultra-cheap Bluetooth door/window sensor that works fully local through a Shelly BLU gateway or BLE proxy.
budget price band
Shelly BLU Motion
Shelly · local control: good · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Budget Bluetooth motion sensor with lux sensing — pair with a BLU gateway for fully local motion-activated automations.
budget price band
Shelly H&T Gen3
Shelly · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Battery-powered WiFi sensor with an e-ink display that shows temperature and humidity without needing an app.
budget price band
Shelly Plus PM Mini Gen3
Shelly · local control: excellent · cloud: none
- Setup: moderate
- Needs extra hub: no / self-contained
- Standout: Pure power monitoring in a tiny inline package — tracks watts, voltage, and energy consumption without switching.
budget price band
SONOFF SNZB-02D
SONOFF · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Integrated LCD with local Zigbee telemetry for both visible and automated climate monitoring.
budget price band
SONOFF SNZB-03P
SONOFF · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: One of the cheapest Zigbee motion sensors available, making whole-house motion detection affordable.
budget price band
SONOFF SNZB-04P
SONOFF · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: One of the cheapest Zigbee contact sensors on the market, making it practical to cover every door and window.
budget price band
SONOFF SNZB-06P Zigbee Occupancy Sensor
SONOFF · local control: excellent · cloud: none
- Setup: moderate
- Needs extra hub: yes
- Standout: Budget mmWave presence detection over Zigbee — detects people sitting still, not just walking by.
budget price band
SwitchBot Contact Sensor
SwitchBot · local control: good · cloud: medium
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Budget contact sensor with bonus motion detection and a path to Matter via Hub.
budget price band
SwitchBot Leak Detector
SwitchBot · local control: good · cloud: medium
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Affordable water leak detection with a local Bluetooth connection and Matter upgrade path.
mid price band
SwitchBot Meter Pro CO2
SwitchBot · local control: good · cloud: medium
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Combined temperature, humidity, and CO2 monitor with e-ink display and Matter support.
budget price band
Third Reality Water Leak Sensor
Third Reality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Cheap and reliable Zigbee water leak detection — scatter several around your home for peace of mind.
budget price band
ThirdReality Door Sensor
ThirdReality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Low-cost Zigbee contact sensing that scales well across many doors and windows.
budget price band
ThirdReality Garage Door Tilt Sensor
ThirdReality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Cheap Zigbee tilt sensor purpose-built for garage door open/close monitoring.
budget price band
ThirdReality Motion Sensor (Matter)
ThirdReality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: no / self-contained
- Standout: Matter-over-WiFi motion sensor. No Zigbee coordinator needed.
budget price band
ThirdReality Motion Sensor R1
ThirdReality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Budget Zigbee PIR sensor with dependable trigger speed for lighting automations.
budget price band
ThirdReality Smart Soil Moisture Sensor
ThirdReality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Zigbee soil moisture and temperature sensing for smart garden automations.
budget price band
ThirdReality Temperature and Humidity Sensor
ThirdReality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Affordable Zigbee temp and humidity sensor with a handy LCD display.
budget price band
ThirdReality Temperature Sensor Lite
ThirdReality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: The cheapest way to get Zigbee temperature and humidity data into Home Assistant.
budget price band
ThirdReality Vibration Sensor
ThirdReality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Cheap vibration and tilt detection for creative home automations.
budget price band
ThirdReality Zigbee Water Leak Sensor
Third Reality · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Ultra-affordable Zigbee water leak detection — cheap enough to put one everywhere water could be a problem.
mid price band
Zooz ZSE11 Q Sensor
Zooz · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Four-in-one Z-Wave sensor: motion, temperature, humidity, and light level in a single compact device.
budget price band
Zooz ZSE18 Motion Sensor
Zooz · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Compact, affordable Z-Wave PIR motion sensor with magnetic mount and USB-C power option.
budget price band
Zooz ZSE42 Water Leak XS Sensor
Zooz · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Tiny water leak sensor that fits anywhere pipes run. Pair with a Z-Wave valve actuator for automated shutoff.
budget price band
Zooz ZSE43 Tilt/Shock XS Sensor
Zooz · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Stick-on tilt and shock sensor for garage doors, cabinets, and gates. No wiring needed.
budget price band
Zooz ZSE44 Temp/Humidity XS Sensor
Zooz · local control: excellent · cloud: none
- Setup: easy
- Needs extra hub: yes
- Standout: Tiny Z-Wave temperature and humidity sensor. Stick it anywhere for local environmental monitoring.