In general the choice of burglar alarms come down to two main types:
- Audio alarms: Which make a very loud and continuous noise when activated
- Monitored systems: When activated, these systems automatically call an alarm centre. The staff will then notify a pre-assigned person that the alarm has been triggered. Sometimes, the police can also be automatically be informed. There will be a monthly or annual fee for this service.
Audio alarms still have a strong deterrent effect on any burglar, who is less likely to break into a house with an alarm, rather than one without. However, with the rise in false alarms which can tend to be ignored, this is less of a deterrent than it used to be. Remotely-monitored alarms offer that extra level of security because any burglar breaking in will know that their activity will have been noticed and that someone will be arriving to investigate very shortly.
Burglar alarms are usually controlled by a key-system or keypad. Most good alarm systems offer zoned cover, so that when the occupants of a property go to bed, the ground floor remains protected, but the upper floors are excluded, enabling the occupants to move around freely upstairs. Many alarms also have a panic button, allowing a householder to call for immediate assistance even if the alarm system is switched off.