How a no-fee alarm system works

A DIY alarm consists of a central hub, door/window sensors, a siren and a mobile app. When a sensor is triggered, the hub activates the siren and sends a push notification to your phone. Everything works over your home WiFi โ€” no monitoring company, no monthly contract.

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No-fee vs monitored alarms

A monitored alarm (with CRA โ€” security company) costs โ‚ฌ20โ€“50/month but ensures a trained operator responds even if you're unavailable. A DIY alarm sends alerts only to your phone. For most homes, a DIY system is perfectly adequate.

System options by budget

Basic

Starter kit

โ‚ฌ80โ€“150

  • Hub + 2 door sensors
  • Internal siren
  • App alerts
  • Battery backup
  • Easy self-installation
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Full home kit

โ‚ฌ200โ€“350

  • Hub + 4โ€“6 sensors
  • External siren (110 dB)
  • Motion detector
  • Camera integration
  • Optional professional monitoring
Advanced

Smart home alarm

โ‚ฌ300โ€“600

  • Full sensor coverage
  • Smart lock integration
  • Video doorbell
  • Amazon Alexa / Google Home
  • Remote arm/disarm

Recommended systems

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Ajax StarterKit

Premium wireless alarm. Encrypted radio protocol (can't be jammed). Expandable. Optional professional monitoring. From โ‚ฌ200.

See price โ†’
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Reolink Alarm Kit

Good value kit with hub, sensors and siren. Integrates with Reolink cameras. App alerts, no monthly fee. From โ‚ฌ100.

See price โ†’
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Ring Alarm

Well-known brand, excellent app, easy installation. Professional monitoring optional (โ‚ฌ8/month). Works standalone for free. From โ‚ฌ150.

See price โ†’
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Somfy Protect

French brand, premium build quality. Indoor and outdoor siren. Optional professional monitoring (โ‚ฌ5/month). From โ‚ฌ180.

See price โ†’

Frequently asked questions

The local siren will still activate. App notifications require internet. Premium systems (Ajax) use GSM backup โ€” they can send SMS alerts even without WiFi. Basic systems only rely on WiFi.
Internal sirens: 85โ€“95 dB. External sirens: 105โ€“115 dB. For reference, 110 dB is louder than a chainsaw. An external siren mounted visibly on the facade is also a significant deterrent โ€” most burglars avoid alarmed properties.