One of the most common questions we get asked is "how much does it cost to have an alarm installed?" It's a fair question — and one that deserves a transparent answer. Too many security companies hide their pricing behind "request a quote" buttons, making it impossible to budget in advance.
As experienced intruder alarm installers in London, we believe in upfront pricing. Here's what you can realistically expect to pay in 2025.
Quick Summary
- →Wireless alarm systems: £500–£800 installed for a typical 3-bed home
- →Wired systems: £800–£1,500 installed — best for new-builds
- →Hybrid systems: £700–£1,200 — the best of both worlds
- →Self-monitoring is free; professional monitoring costs £15–£30/month
- →Always ask about hidden fees: monitoring contracts, call-out charges, app subscriptions
Average Alarm Installation Costs in London
Prices vary depending on the type of system, number of sensors, and property size. Here's a realistic breakdown:
Wireless Alarm
£500–£800- 4 PIR motion sensors
- 1 door contact
- Siren + control panel
- Smartphone app included
- Professional installation
Wired Alarm
£800–£1,500- Superior reliability
- No battery changes
- Tamper-resistant cabling
- Ideal for new-builds
- Professional installation
Hybrid System
£700–£1,200- Wired control panel
- Wireless sensors
- Best of both worlds
- Flexible positioning
- Professional installation
Our most popular option
What Affects the Price?
Number of Sensors
Each additional sensor (PIR, door contact, or window sensor) usually adds £30–£80, depending on sensor type and whether the system is wired or wireless.
- Typical flat: 3–4 sensors
- Typical detached house: 8–12 sensors
Property Size and Layout
Larger properties need broader coverage, which increases both equipment and labour time.
- Multi-storey homes may need extra keypads
- Outbuildings, garages, and annexes require additional zones
- Complex layouts can require signal repeaters for wireless systems
Monitoring Options
Your ongoing monthly cost depends on how you monitor the system.
- Self-monitoring: £0/month (app alerts only)
- Professional monitoring: typically £15–£30/month
- Police response (URN): often adds ~£40–£60/year
Smart Home Integration
Integration with smart home platforms, voice assistants, or linked systems like CCTV can increase upfront cost, but many homeowners value controlling everything from one app.
Want a fixed price for your property?
We provide free, itemised quotes with zero hidden extras. No obligation.
Hidden Costs to Watch For
Before you sign anything
Common hidden charges
- Monthly monitoring fees — and minimum contract length
- Maintenance charges — some companies charge for annual servicing
- Call-out fees — charges for false alarm resets or technical issues
- Battery replacement costs — wireless sensors need changes every 2–3 years
- Software subscription fees — some brands charge for app access or cloud storage
At Eagle All Security, we don't tie you into contracts. You own your system outright, and our app access is included free. We believe in earning your loyalty through quality, not locking you in through clauses.
Is a Cheap Alarm Worth It?
DIY alarm kits available online for £100–£200 can provide basic deterrence, but they typically lack the reliability, sensor quality, and professional positioning that makes a system genuinely effective.
A poorly positioned sensor creates false alarms (which you'll eventually ignore) or misses genuine intrusions. Professional installation ensures every sensor is optimally placed based on your property's specific vulnerabilities.
Key Takeaway
How to Save Money Without Compromising Security
Smart ways to reduce cost
- Start with essentials: Cover entry points and high-risk areas first, then expand later
- Choose self-monitoring: Smartphone alerts are free and instantly notify you
- Bundle services: Combining alarm and CCTV installation often reduces the overall cost
- Check our specials: Our current offers page always has value-for-money packages
Get a Fixed Price Quote
We provide free, no-obligation site surveys across all our service areas in London and the Home Counties. After assessing your property, you'll receive a clear, itemised quote with no hidden extras. Contact us today or call 02036 330809.
Eagle All Security
Family-run security specialists protecting homes and businesses across London & the Home Counties since 2014. All advice is based on hands-on installation experience.
