The house is empty. Someone is still paying attention - Guardian watches any building that stands empty.
Silence is an alarm.
A small wireless kit for any building that spends time empty - which is most of them, most of the time. It senses frost, leaks, power loss and open doors, and anything sudden reaches you within seconds, over its own cellular link. Built in Denmark.
- HUB-01 · MAIN UNITMAINS OK · LTE −97 dBm
- NODE-01 · LIVING6.0 °C · RH 57 % · BAT 91 %
- NODE-02 · KITCHEN4.8 °C · FREEZE WATCH
- NODE-03 · BEDROOM5.1 °C · RH 58 % · BAT 94 %
- PEB-01 · TECH ROOMDRY · HEARTBEAT OK
- PEB-02 · BATHDRY
- LATCH-E · EAST DOORCLOSED · 41 d
Whatever stands empty,
watched.
Water finds the floor in January. Frost finds the pipes. Power fails quietly. A house, a workshop, an office over a long weekend - the risks do not care which. Guardian sits in the building year-round and reports over its own cellular connection, and when anything goes wrong, you hear about it in seconds.
- Frost & temperatureFreeze warnings before pipes burst - down to floor level.
- Water leaksPebbles at every wet spot - alarm on contact.
- Power failureReported in seconds, keeps running on battery.
- Humidity & moldSlow-trend alerts, room by room.
- Doors & windows“Did I leave the back door open?” - answered, instantly.
- Unexpected presenceMovement when nobody should be there.
Silence is an alarm.
If your building stops reporting - cut power, dead battery, stolen box - the Guardian cloud alerts you. Every device carries a heartbeat, and the watchdog that listens for them runs on infrastructure independent of everything it watches. It cannot fail quietly.
The storm takes the grid at 02:41:03.
You know at 02:41:12.
- 21:00:12Scheduled report - house 6.2 °C · RH 61 % · mains ok · all devices reporting.
- 02:41:03Mains power lost. A winter storm takes the grid along the coast. The hub detects the drop and publishes the event before switching to its backup battery.
- 02:41:09Alert raised - 6 seconds after the grid dropped. Well inside the design target of ten.
- 02:41:12SMS and e-mail delivered. App push sent. No app required - text and mail are first-class paths.
- 03:41:07Battery heartbeat - Hub at 96 %, house 6.1 °C. Guardian keeps reporting hourly for more than a day on backup.
- 09:27:44Mains restored. All-clear sent - outage 6 h 46 min, backup recharging.
- 09:30:00System nominal. The house never knew you weren't watching.
The actual alert copy. Calm on purpose.
Five quiet machines.
Turn them over.
One Hub carries the property’s single cellular connection. A Node, a Pebble and a Latch ship with it, reaching it over long-range radio that covers the whole building and its outbuildings. More of any of them can join the same link, and a plug-in Relay stretches it to the far shed. Magnetic and half-turn closures, tape mounts - zero screws.
Hub 120 × 80 × 25.5 mm
Mains-powered with battery backup, cellular built in. The property’s one connection to the world.
Node 72 × 54 × 17 mm
Any room - temperature, humidity, light and presence on a two-year battery.
Pebble Ø45 × 23 mm
Lives at the wet spots - senses water on either face, frost at the floor, and being moved.
Latch 72 × 30 × 17 mm
One in every kit, with a slim magnet bar and shims for old frames. Opens are sent instantly.
Relay 50 × 50 × 14 mm
A socket halfway to the barn, and the barn joins the house. Always listening, one clean hop.
How it goes in.
Place it
Tape the units to the wall, drop Pebbles at the wet spots. Five minutes, no tools - the tape is magnetic.
It links up
Rooms talk to the Hub over long-range radio that covers the whole building and its outbuildings.
You hear first
One built-in cellular connection reports to the cloud - alerts by app, SMS and e-mail.
Built for the empty building,
not the smart home.
| Guardian | Typical smart-home gear | |
|---|---|---|
| Connection | Own cellular link, one SIM per property | Your Wi-Fi router - which needs mains power |
| Power cut | Alert in under 10 s, then > 24 h on battery | Goes dark with the building |
| When hardware dies | The silence itself raises an alert | Silent failure; you find out in April |
| Sensor battery | Years on lithium primaries, rated to −40 °C / −40 °F | Months, indoor-rated |
| Cameras & microphones | None. Not disabled - absent | Camera-first, footage in someone's cloud |
| Alerts without the app | SMS and e-mail are first-class paths | Push notification or nothing |
“Typical” describes mainstream Wi-Fi security and camera products; specifics vary by vendor.
No camera. No microphone.
Ever.
Not a toggle in the settings. Not a firmware promise. There is no lens and no mic on the bill of materials - so there is nothing to hack, nothing to leak, nothing to subpoena.
What Guardian knows
- The east door opened at 02:41
- The bedroom is 4.1 °C and falling
- There is water on the floor by the heater
- The mains power is out
- Something moved while the building stood empty
What it can never know
- What any room looks like
- What any voice sounds like
- Who anyone is
- What you left on the kitchen table
- Anything a camera would know
Your building stays yours. Guardian reads instruments, not rooms.
Twenty-five buildings. One winter. Every alert accounted for.
Guardian is in development, heading into a pilot in Denmark and the US this winter. If you own, manage, sell or insure a building that stands empty - we’d like one of the twenty-five to be yours.
What pilot sites get
A full Guardian kit and its cellular connection, free for the pilot winter - six months.What we ask
A building that stands empty, mains power at one socket - and your honest verdict on every alert we send.What happens when you apply
A person reads it and replies. If it fits, your building is one of the twenty-five.The kit comes with the subscription and stays ours to replace when something fails.
No list, no drip, no salesperson. Or just write hello@kresvik.com