A home alarm system is one of the few security investments with a dual return: it deters burglars and can reduce your home insurance premium. According to the Office for National Statistics, homes without security measures are roughly five times more likely to be burgled than those with visible deterrents. But the market ranges from a £50 wireless DIY kit to a £3,000 professionally installed, centrally monitored system — and choosing the wrong type can mean spending money on protection that either does not work or is not recognised by your insurer.
The Four Main Types
Bells-Only (Audible Only)
The most common type in UK homes. When triggered, it activates a siren (typically 85–103 dB) on the exterior bell box. No signal is sent anywhere — the noise is the deterrent. Depends entirely on neighbours or passersby responding. Effective as a deterrent; less effective at night when neighbours may not hear or react.
Monitored (Professionally Monitored)
When triggered, the alarm dials out to an Alarm Receiving Centre (ARC) staffed 24/7. The ARC contacts your keyholders and, if they cannot be reached or confirm an intruder, alerts the police. To receive a police response, the installation must meet the requirements of BS EN 50131 and be installed by an NSI Gold or SSAIB-approved company. Police use a URN (Unique Reference Number) grading system; a Grade 2 system installed to the correct standard gets a police response; lower grades may not.
Smart / App-Based
Systems such as Ring Alarm, Ajax, or Yale SmarHome connect to your home Wi-Fi and push notifications to your smartphone when triggered. Many offer optional professional monitoring as an add-on (£5–£15/month). Convenient and increasingly capable, but dependent on mains power and internet connectivity. Not all smart alarm systems are NSI/SSAIB-approved and may not qualify for insurance discounts.
DIY Wireless
Budget kits (£50–£300) from brands sold at Screwfix, B&Q and online retailers. Magnetic contacts, PIRs and a hub. Suitable for low-risk properties or as a supplementary deterrent. Almost never qualify for insurer discounts and do not receive a police response. Useful for peace of mind; not equivalent to a professional installation.
Cost Breakdown (2026)
| System Type | Supply & Install | Ongoing Cost |
|---|---|---|
| Bells-only (4–6 zones) | £300–£700 | Maintenance contract: £80–£150/yr (optional) |
| Monitored (NSI/SSAIB Grade 2) | £600–£1,500 | Monitoring: £15–£40/month; maintenance: £120–£200/yr |
| Smart alarm (DIY, mid-range) | £150–£400 (DIY) | Optional monitoring: £5–£15/month |
| Smart alarm (professional install) | £400–£900 | Monitoring: £10–£25/month |
| CCTV + alarm combined package | £1,200–£3,000 | Monitoring (if any): £20–£50/month |
Higher prices reflect larger homes (5+ bedrooms), additional detection zones, access control integration or rural locations requiring specialist installers.
Key Components
A standard system includes:
- Control panel — the brain, usually housed in a metal enclosure in a cupboard
- Keypad(s) — for arming/disarming; LED or LCD; typically one at front door and one at back
- PIR detectors — passive infrared motion detectors; one per room typically; wall-mounted at 2.0–2.4 m height
- Door/window contacts — magnetic sensors that trigger if an opening is forced
- Bell box — external siren with flashing strobe; must be tamper-proof and self-powering (battery backup) for BS EN 50131 compliance
- Communicator — for monitored systems; dials the ARC via telephone or mobile SIM
Optional extras: CCTV integration, smart locks, glass-break detectors, panic buttons, CO/flood sensors.
NSI and SSAIB: Why Certification Matters
For insurance purposes and police response, the installation must be carried out by a company certified by either the National Security Inspectorate (NSI) or the Security Systems and Alarms Inspection Board (SSAIB). These bodies carry out annual inspections of member companies’ work and ensure compliance with the relevant British and European standards.
Most major insurers (Aviva, LV=, Direct Line, Admiral) offer discounts of 5–15% on home insurance premiums for NSI or SSAIB-approved systems. Verify with your insurer before paying for an installation — some require the system to meet a specific grade.
You can find NSI Gold and SSAIB members via their respective websites, or via the police-run initiative Secured by Design, which maintains a directory of approved security products and installers.
False Alarms
False alarms are a significant practical issue. Nationwide statistics show that around 95% of alarm activations are false — triggered by insects, pets, draughts, steam or user error. Repeated false alarms can result in your police URN being withdrawn, meaning the ARC can no longer request a police response. Most monitored systems build in a sequential verification step (two detectors must trigger within a defined period, or CCTV verification) to reduce false call-outs.
Practical steps to reduce false alarms:
- Install pet-immune PIR detectors (rated ≤ 20 kg) if you have animals
- Set the entry/exit delay correctly — allow enough time to disarm without rushing
- Service the system annually; faulty detectors are the most common cause of random triggers
What to Ask Before Buying
- Is the installer NSI Gold or SSAIB certified?
- Does the system meet Grade 2 of BS EN 50131?
- What is the total cost including installation, commissioning and first year’s monitoring/maintenance?
- What happens if the broadband or phone line goes down — does the system have mobile SIM backup?
- Who owns the equipment — can I switch monitoring companies without buying new hardware?
Avoid any installer who cannot answer these questions clearly. A reputable security company will provide a written specification and a commissioning certificate on completion.
