How Unmonitored (Bells-Only) Alarms Work
An unmonitored alarm sounds a loud external siren when triggered. The theory is that this noise deters the intruder and alerts neighbours who will call the police. In practice, studies show that bell-only alarms are widely ignored in urban areas — London residents are so accustomed to alarm sounds that most do not call police. Average police response to a self-reported alarm in London can be 30–60 minutes. By that time, a burglar has typically been and gone.
How Monitored Alarms Work
When a monitored alarm activates, the signal reaches a staffed ARC within seconds. Trained operators verify the alarm (using audio or video verification where available), contact your nominated keyholders and, if warranted, request a police response under your alarm's URN. Police response to a confirmed activation is typically under 10 minutes.
Insurance Requirements in London
The majority of London home insurance policies now specify monitored alarms (installed by NSI or SSAIB-approved companies) as a policy condition for higher value homes. Failing to maintain a monitored system can invalidate your policy at the point of claim — a catastrophic outcome after a burglary.
Cost Difference
Adding professional monitoring typically adds £15–£25/month to the cost of an alarm system. For the substantial improvement in protection — particularly for properties left empty during the working day, holidays or overnight — this represents excellent value.
Enquire About Monitored Alarms
24/7 monitoring from our NSI-approved ARC. London coverage.