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Water Leak Sensors · Head to head

Kidde WiFi Water Leak & Freeze Detector vs Shelly Flood Gen4

Full Smart Water Leak Sensors comparison in 2026

Updated October 2026
Data from Amazon and official Kidde and Shelly sites.
2026 verdict
If one sensor has to fit several ecosystems, the Shelly Flood Gen4 is the stronger buy over the Kidde WiFi Water Leak & Freeze Detector.
Shelly Flood Gen4
Winner
Shelly Flood Gen4
$39.99
Buy on Amazon USA
It speaks Wi-Fi, Bluetooth, Zigbee and Matter at once, charting into HomeKit, SmartThings, Google Home and Home Assistant, and it adds a 2 m sensor cable, an IP44 housing and a three-year warranty. The Kidde WiFi Water Leak & Freeze Detector stays cheaper and simpler, joining Wi-Fi with no hub, but it is locked to Google Home and Home Assistant and its battery life is undocumented. Pick the Shelly for protocol flexibility and the probe cable, and the Kidde for the lowest price.
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FeatureKidde WiFi Water Leak & Freeze DetectorShelly Flood Gen4Winner
Price$23.92$39.99Kidde WiFi Water Leak & Freeze Detector
Rating4.04.2Shelly Flood Gen4
Warranty1 year3 yearsShelly Flood Gen4
Weather ResistanceNOIP44Shelly Flood Gen4
Connectivity2.4 GHz WiFi2.4 GHz WiFi, Bluetooth, ZigbeeShelly Flood Gen4
IntegrationsGoogle Home, Home AssistantGoogle Home, Apple HomeKit, Samsung SmartThings, Home Assistant, MatterShelly Flood Gen4
SensorsWater Leak, TemperatureWater Leak, TemperatureTie
AlertsWater Leak Alerts, Temperature Alerts, Freeze Temperature Alerts, Low Battery AlertsWater Leak Alerts, Temperature Alerts, Freeze Temperature Alerts, Low Battery AlertsTie
On Device Alert SoundYESYESTie

What the differences mean

Protocols

The Shelly Flood Gen4 supports 2.4 GHz Wi-Fi, Bluetooth, Zigbee and Matter in one device, so it can join several kinds of network. The Kidde speaks 2.4 GHz Wi-Fi only.

Ecosystems

The Shelly reaches Google Home, Apple HomeKit and SmartThings (the last two through Matter) plus Home Assistant. The Kidde works with Google Home and Home Assistant, with no HomeKit, SmartThings or Matter.

Warranty

The Shelly carries a three-year warranty, the longest of the pair. The Kidde comes with one year.

Probe cable

The Shelly ships a 2 m extendable sensor cable, so the body can sit somewhere accessible while the cable reaches under a cabinet or into a crawlspace. The Kidde has no cable and detects only where it sits.

Battery

The Shelly runs about two years on four AA cells. The Kidde uses two AA cells but does not document a runtime.

Price

The Kidde is the cheaper of the pair, which suits a house that wants several simple sensors. The Shelly costs more but carries the multi-protocol radio, the cable and the longer warranty.

Which one to buy if

  • one sensor has to work across several ecosystems
    Shelly Flood Gen4

    The Shelly Flood Gen4 supports Wi-Fi, Bluetooth, Zigbee and Matter, reaching HomeKit and SmartThings through Matter.

  • you need a probe under a cabinet or in a crawlspace
    Shelly Flood Gen4

    The Shelly ships a 2 m extendable sensor cable; the Kidde has none.

  • you want the cheapest simple leak and freeze puck
    Kidde WiFi Water Leak & Freeze Detector

    The Kidde costs less, joins Wi-Fi with no hub and still covers water, temperature and freezing pipes.

  • you want the longest warranty
    Shelly Flood Gen4

    The Shelly Flood Gen4 is backed for three years against the Kidde's one.

  • you want Apple Home or Matter
    Shelly Flood Gen4

    The Shelly reaches Apple HomeKit and SmartThings over Matter, which the Kidde does not support.

What owners say

Owners of both sensors describe an alert that arrived in time, and both groups value being able to leave the device in place. Shelly Flood Gen4 owners, mostly on Home Assistant and Zigbee2MQTT, praise a cable sensitive enough to trip on a single drop, a built-in buzzer and LED that warn without the app, local automations that can cut power to a pump and a three-year warranty; their friction is slow Wi-Fi onboarding and a Matter or HomeKit status that sometimes needs a manual button press. Kidde WiFi Water Leak & Freeze Detector owners value the hub-free Wi-Fi setup and freeze alerts, and their recurring complaints are Wi-Fi pairing, a hard-to-open battery compartment and a temperature reading that refreshes only every twelve hours.

Price history compared

Every price change of both, in the same store, so the gap between the two lines is what one costs more than the other.

  • Kidde WiFi Water Leak & Freeze Detector
  • Shelly Flood Gen4

Loading price history...

Frequently Asked Questions

Which is better overall: Kidde WiFi Water Leak & Freeze Detector or Shelly Flood Gen4?

The Shelly Flood Gen4 for a mixed smart home. It covers Wi-Fi, Bluetooth, Zigbee and Matter, ships a 2 m sensor cable and carries a three-year warranty. The Kidde WiFi Water Leak & Freeze Detector is the better buy on price for a simple hub-free Wi-Fi sensor that covers leaks, temperature and freezing.

What is the biggest difference between the Kidde WiFi Water Leak & Freeze Detector and the Shelly Flood Gen4?

Connectivity. The Shelly Flood Gen4 speaks Wi-Fi, Bluetooth, Zigbee and Matter and reaches HomeKit and SmartThings through Matter, while the Kidde WiFi Water Leak & Freeze Detector is Wi-Fi only and limited to Google Home and Home Assistant.

Does the Shelly Flood Gen4 need a hub?

No. It can connect directly over 2.4 GHz Wi-Fi, and it also supports Zigbee and Matter for homes that already run those hubs.

Does the Kidde WiFi Water Leak & Freeze Detector work with Matter?

No. It supports Google Home and Home Assistant over 2.4 GHz Wi-Fi, with no Matter, Apple HomeKit or SmartThings support.

Do both detect freezing pipes?

Yes. Both sense water and temperature and raise freeze alerts, and both support low-battery alerts.

Who should buy the Kidde WiFi Water Leak & Freeze Detector?

Anyone who wants a low-cost, hub-free Wi-Fi sensor that covers leaks, temperature and freezing and works with Google Home or Home Assistant.

Who should buy the Shelly Flood Gen4?

A DIY smart home that wants one sensor to fit Wi-Fi, Zigbee or Matter, a probe cable for hard-to-reach spots, and a three-year warranty.

Full comparison table

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