What actually drives the cost
Capital cost is dominated by detection technology — number of zones, sensor type, perimeter length and CCTV count. The next biggest driver is the monitoring model: keyholder vs ARC, event-only vs continuous, video verification vs unverified alarm.
Install cost depends heavily on the building. Retrofit into occupied or finished space costs more than first-fix new build. Network, lighting and containment are often hidden costs that aren't in the headline number.
- Sensor count and technology
- Perimeter length and lighting
- Monitoring model (ARC, keyholder, verified)
- Install environment (retrofit vs new build)
- Network, containment and power
- Grade requirement (insurer-driven)
What commercial sites actually pay
Ranges below are commercial price bands — not domestic. They assume monitored systems to recognised grading and exclude major civils, lighting upgrades and structured cabling.
Ongoing monitoring & maintenance
Monitored alarm signalling typically runs £15-£60 per month per site for unverified, more for video-verified. Monitored CCTV (event-driven) typically runs £8-£30 per camera per month plus bandwidth.
Annual maintenance and inspection should be budgeted at 8-12% of capital for credible service levels.
How to compare quotations
Comparable quotes specify: number and grade of sensors, signalling path (single/dual), monitoring model, response pathway, lifecycle replacement schedule and exclusions. If any of those are missing, the quote is incomparable.
Indicative commercial intruder detection system cost
Capital plus first-year monitoring — UK ranges, commercial grade, excluding major civils.
| Feature | Small site | Mid-sized site | Large / complex site |
|---|---|---|---|
| Intruder alarm (zones) | 8-16 | 20-60 | 60-200+ |
| Internal CCTV cameras | 4-8 | 12-32 | 40-150+ |
| Perimeter CCTV / PIDS | — | Optional | Typical |
| Capital install | £3.5k-£8k | £15k-£45k | £60k-£200k+ |
| Monitoring (year 1) | £300-£900 | £1.5k-£5k | £8k-£30k+ |
| Annual maintenance | £300-£700 | £1.2k-£3.5k | £6k-£20k+ |
In summary
- Cost is dominated by detection layer count and monitoring model.
- Retrofit installs are materially more expensive than first-fix.
- Maintenance + monitoring typically equal 25-40% of capital across a decade.
- Insist on like-for-like quote structure to make comparison meaningful.
Frequently asked questions
Is there a cheaper way to monitor than an ARC?
Self-monitoring (app alerts to nominated staff) is cheaper but rarely meets insurer or response requirements for commercial premises. ARC monitoring is the commercial default.
Can I reduce cost by using existing cameras?
Often yes — analytics platforms can ingest existing IP streams. Older analogue or first-generation IP cameras may not meet detection requirements.
How much of the ten-year cost is monitoring rather than kit?
On a typical mid-sized commercial installation, monitoring and maintenance together account for around fifty to sixty percent of the total ten-year cost. Capital kit dominates year one; recurring ARC fees, keyholder retainers and preventative maintenance visits accumulate to overtake the install cost within about seven years on most sites.
What's typically excluded from a headline quotation?
Common exclusions are structured cabling, containment, supplementary perimeter lighting, network switches, keyholder retainers, out-of-hours engineer call-outs and lifecycle replacement provisions. A quote at the low end of the range usually excludes several of these. Ask for an itemised exclusions list before comparing two suppliers on price alone.
Do wireless systems cost less than wired?
Wireless installations are typically twenty to thirty percent cheaper to install because there is no cable containment work, and disruption to occupied space is minimal. Total ten-year cost is broadly comparable once battery replacement, additional maintenance visits and the shorter equipment lifecycle of wireless sensors are factored in properly.
How does insurer grade requirement affect the cost?
Moving from Grade 2 to Grade 3 typically adds fifteen to thirty percent to capital cost, driven by higher-specification sensors, tamper protection, dual-path signalling and stricter installer certification. Grade 4 systems are another step up and are usually reserved for high-value or specifically insurer-mandated commercial premises rather than the general market.
Should I capital-purchase or lease a commercial system?
Capital purchase is usually cheaper across a ten-year horizon because managed-service pricing embeds financing costs and margin. Leasing or managed service can make sense where cash flow matters, where a single supplier is accountable for uptime, or where technology refresh in five years is likely — a common pattern on retail estates.
How much should I budget for annual maintenance?
Eight to twelve percent of capital is a reasonable annual maintenance budget for credible service levels on a commercial system. This covers preventative visits, remote inspection, minor part replacement and software updates. Below eight percent, service quality typically slips; above twelve percent, the contract is usually over-specified for the actual site risk.
Talk through this with a specialist for your site
Tell us about your site and we'll connect you with a commercial security specialist who understands your detection, monitoring and response requirements.