Sirens with high-decibel alarms (100dB or more) are most effective for alerting occupants and scaring off intruders. Many modern alarms also feature:

• Integrated strobes for a visual deterrent
• Smart notifications to instantly alert property owners via mobile apps
• Customisable sound levels for different areas (e.g., louder for external breaches, softer for internal motion detection)

For businesses, silent alarms linked to security monitoring services can be beneficial, notifying authorities without alerting intruders.