1) Fast deterrence. A loud siren (≈90–120 dB) startles an intruder and draws attention.
2) Early warning. You hear the alert the moment the window opens or vibrates.
3) Works even if Wi-Fi is down. Local sound gives you backup when the internet or app fails.
4) Layered security. Pairs well with door sensors, motion sensors, and cameras.
5) Kid and pet safety. Alerts you if a child opens a window or a pet pushes a latch.
6) Simple install. Most use peel-and-stick tape; no drilling for standard frames.
7) Low upkeep. Long battery life and a low-battery beep in many models.
8) Tamper notice. Some siren units chirp if someone tries to remove them.
9) Flexible modes. Chime mode for daytime, full siren at night, delay options for airing out rooms.
10) Budget friendly. Adds coverage to many windows for a small cost per sensor.
Dual sensing: contact + vibration to catch both opening and forced entry.
Volume control: set chime for kids, max siren for break-in.
App alerts: push/SMS if the model supports hubs or Matter/Thread.
Zones/labels: name each window for faster response.
Mount the magnet and sensor level and close (1–2 mm gap).
Test with the window barely cracked and fully open.
Avoid metal frames or place a thin spacer if signal drops.
Replace batteries in pairs and note the date inside the cover.
Contact sensor + siren: best for standard sliding or casement windows.
Glass-break sensor: add near large panes or fixed glass that does not open.
Vibration sensor: use on older frames where alignment is tricky.
Door/window contact + optional vibration
Siren loudness (≥100 dB for main floors)
Modes: chime / instant / delayed
Battery type and expected life
Integration: works with your hub (Alexa, Google Home, HomeKit, Matter)
Tamper switch and low-battery alert
Mounting with a wide gap, causing missed triggers.
Relying on app alerts only; keep local sound enabled at night.
Ignoring false alarms from slamming windows—use vibration sensitivity or chime mode to tune.
Bottom line: A window sensor with a built-in alarm gives fast, local alerts, scares off intruders, and adds a low-cost safety layer for families and renters.