The water leak sensor is the one most homes skip and most regret skipping. It costs very little, needs no wiring, and catches the failure that does the most expensive damage — a slow leak under a sink or behind a washing machine, discovered days later.
Water leak sensor
A small unit placed on the floor at the lowest point near a water source. It alerts the moment its contacts get wet.
Place them under sinks, behind the washing machine, near the water heater, and by any pipe junction in a cupboard. These are precisely the places nobody looks.
Paired with a smart valve, a leak can trigger an automatic shutoff. Even without that, an alert hours after a leak starts rather than days later changes the outcome entirely.
Motion sensor
Two distinct jobs, often confused:
- Convenience — lights on entry in stairwells, corridors, storerooms and bathrooms. Set a generous timeout; a light that dies while you are still in the room is worse than no automation.
- Security — alerts when nobody should be home. Useful, but expect occasional false triggers from pets and moving curtains.
Mount them so the detection field covers the entrance, not the middle of the room. People trigger a sensor best when moving across its field rather than towards it.
Door and window sensor
Two magnetic halves reporting open or closed. Simple, and more useful than it sounds.
- Alerts when a door opens while the house is empty.
- Air conditioning automation — stop the unit when a balcony door is left open.
- Reminders — a fridge or a front door left ajar.
Temperature and humidity sensor
Best used as a trigger rather than a readout.
Practical uses in Egyptian homes: switch a fan or air conditioner when a room passes a threshold, monitor a server or equipment cupboard that overheats in summer, and track humidity in rooms prone to damp.
Smoke and gas detectors
Different category, and the priority order is straightforward. A working smoke alarm matters far more than any convenience automation. Smart versions add remote alerts, which is genuinely valuable when nobody is home — but the alarm sounding locally is the part that saves lives.
Gas detectors matter where bottled gas is used. Place them according to whether the gas is heavier or lighter than air, not simply on the ceiling by default.
Batteries and maintenance
Most sensors run on batteries for a year or more. The failure mode to plan for is silent: a dead sensor reports nothing, which looks identical to nothing happening.
Check battery levels in the app monthly, and replace on a schedule rather than waiting. A leak sensor with a flat battery is decoration.
A sensible starting set
- Water leak sensors under every sink and behind the washing machine.
- A motion sensor in the stairwell or main corridor.
- Door sensors on external doors.
- Temperature sensors where you have a specific automation in mind.
See smart sensors and smart cameras.
Frequently asked questions
Do sensors work without internet?
Local automations through a hub continue; remote alerts need internet.
How long do batteries last?
Typically a year or more, depending on how often the sensor triggers.
Will pets set off motion sensors?
Sometimes. Mount higher and angle away from floor level to reduce it.