Water damage is the most boring disaster there is. No drama, no warning — just a slow drip behind the washing machine that turns into a four-figure repair bill. So leak sensors were always going to be early additions to my setup. Right now there are two interesting candidates at very different price points: the Shelly Flood Gen4 (~€30) and IKEA’s new KLIPPBOK (~€7). I dug into both to decide what goes where in my house.
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Two very different philosophies
These aren’t really the same product at different prices — they’re two answers to different questions.
The KLIPPBOK is a classic spot sensor: a small pill-shaped puck (17 × 70 × 40 mm) with two metal probes on the underside. Water touches the probes, it screams — the built-in siren is genuinely loud up close — flashes orange, and reports the leak over Matter-over-Thread. At €6.99 it’s priced like an impulse buy at the checkout, which is exactly what IKEA wants it to be.
The Shelly Flood Gen4 thinks bigger. Instead of probes on the bottom, it uses a 2-metre leak sensor cable that detects water along its entire length — and you can chain additional cables up to a frankly absurd 150 metres. It also speaks more languages than most smart home devices: Wi-Fi, Bluetooth, Zigbee, and Matter, switchable via the button (Matter firmware is the default; five rapid presses flips it to Zigbee). Add three alarm-intensity modes, a rain-detection mode for outdoor automation, MQTT, webhooks, and a built-in web interface, and it’s less a sensor than a small platform.
Head to head
| Shelly Flood Gen4 | IKEA KLIPPBOK | |
|---|---|---|
| Price | ~€30 / $33 | ~€6.99 / $7.99 |
| Protocol | Wi-Fi, Bluetooth, Zigbee or Matter (switchable) | Matter-over-Thread only |
| Detection | 2 m sensor cable, extendable to 150 m | Two point probes on the underside |
| Local siren | Buzzer, 3 alarm modes (Intense/Normal/Economic) | Loud built-in siren, one behaviour |
| Batteries | 4× AA (included), ~2 years | 2× AAA (not included) |
| Extras | Rain mode, MQTT, webhooks, web UI, IP44 | LED indicator, firmware updates via Matter |
| Size | 97 × 76 × 25 mm | 17 × 70 × 40 mm |
| Works without any hub? | Yes (Wi-Fi + app/web UI) | Siren works standalone; smart features need a Thread border router |
How they fit a Home Assistant setup
The KLIPPBOK is tailor-made for the Thread network I just built around the ZBT-2 border router. Pop in two AAAs, scan the Matter QR code in the companion app, done — fully local, no IKEA DIRIGERA hub, no cloud account. (The usual Matter caveats apply: IPv6 enabled, phone on the same network as HA while pairing.)
The Shelly gives you options. In Matter mode it commissions like any Matter device; in Zigbee mode it joins ZHA or Zigbee2MQTT. But the sleeper feature for Home Assistant users is Wi-Fi mode with MQTT and webhooks — the sensor can directly trigger a Shelly smart valve or relay to shut off the water main, even if your HA server happens to be down. For a failure-of-last-resort device, that independence is worth something.
The fine print nobody mentions
Two honest caveats from real-world testing rather than spec sheets.
First, the KLIPPBOK’s rubber feet hold its probes roughly 2 mm above the floor — so a thin film of water creeping across a slightly sloped floor may never reach them. It’s more a “flood detector” than a “leak detector”. For a drip-tray under a boiler it’s fine; for catching the first millimetre of water it’s not ideal. The Shelly’s cable lies flat on the floor and triggers anywhere along its length, which is simply a better detection mechanism.
Second, reliability. Early reports on IKEA’s Matter-over-Thread range include occasional pairing hiccups and devices briefly flapping between connected and disconnected. A strong Thread mesh (mains-powered Thread routers nearby) helps a lot. The Shelly checks its sensor every 5 seconds to save battery, so detection isn’t quite instant — and high humidity or a cable touching metal pipes can cause false alarms, fixable with the configurable state-hold time.
My verdict: it’s not either/or
At a 4:1 price ratio, this is a placement question, not a brand war.
KLIPPBOK for volume: under every sink, behind the toilet, next to the dishwasher. At €7 each you can blanket the house for the price of two Shellys, and every one of them strengthens the case for the Thread network you already run.
Shelly Flood Gen4 for the critical spots: the utility room, along the washing machine and boiler plumbing, anywhere a cable snaked along the pipes beats a puck on the floor — and anywhere you want the sensor to slam a water valve shut on its own, no questions asked.
That’s the plan for my house: one Shelly guarding the utility room, a handful of KLIPPBOKs everywhere else. Total cost: less than a single visit from a plumber.
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