You don’t need to spend a fortune to protect what matters most. Here are the top smart alarm systems that keep your home safe without emptying your wallet.
Introduction
Professional security systems can cost hundreds upfront and lock you into monthly contracts. But what if you could get smart protection for less than a takeaway delivery?
Here’s what I’ve learned: you don’t need to spend a fortune to feel safe. Premium systems from SimpliSafe or ADT come with contracts, installation fees, and ongoing costs. For many UK households – renters, students, or anyone on a tight budget – a simpler approach works perfectly.
Smart alarms system under £100 now offer DIY installation (no drilling, no electrician, no landlord permission), no monthly fees, smartphone control, expandable sensors, and Alexa or Google compatibility.
In this guide, I’ve scoured Amazon UK to find the best smart alarms that keep your home secure and your bank account happy – all for under £100.
Quick Reference Comparison Table
| System | Hub | Included Sensors | Siren | Voice Control | Expandable | Best For |
|---|---|---|---|---|---|---|
| LWOHSI GSM/WiFi Alarm | Main controller | PIR motion + door sensor | 120dB | Alexa | ✅ Yes | Cellular backup, unreliable broadband |
| HESTIA Smart System | Cube hub | 2x contact, 1x vibration, 2x fobs | Not specified | Alexa, Google | ✅ Up to 96 sensors | Renters, small flats, award-winning design |
| Eufy 5-Piece Kit | HomeBase | 2x door, 1x motion, keypad | 100dB | Alexa, Google | ✅ 50+ devices | Premium experience, future expansion |
| Ring 5-Piece Kit | Base station | Contact + motion + keypad + extender | Built-in | Alexa only | ✅ Yes | Alexa households, ecosystem building |
See also: 4G Backed Smart alarms | Best Compact Smart Alarms UK
The Contenders – Smart Alarms Systems Under £100
LWOHSI WiFi + GSM Home Security Alarm System – The Cellular Backup Champion
The LWOHSI alarm system stands out in the budget category by offering both WiFi and GSM cellular connectivity – a rare feature at this price point. If your broadband goes down or someone cuts your internet line, this alarm keeps working.
Check Availability
LWOHSI WiFi + GSM Home Security Alarm System.
What Makes It Special
Dual Connectivity
Most budget alarms rely solely on WiFi. If your internet goes down, they’re useless. The LWOHSI system adds GSM cellular backup, meaning it keeps working even without broadband . This is professional-grade resilience at a budget price.
120dB Siren
At 120dB, this is one of the loudest alarms in its class – enough to wake the neighbourhood and send intruders running .
App Control with Instant Alerts
The Smart Life app sends push notifications the moment a sensor is triggered, keeping you informed wherever you are.
Who Should Buy It
Ideal for: Homes in areas with unreliable broadband, anyone wanting professional-style resilience on a budget, and those who want the peace of mind that comes with cellular backup.
Not ideal for: Those wanting a well-known brand name or integrated camera system.
HESTIA Smart Home Security System – The Award-Winning Compact Choice
The HESTIA system proves that good things come in small packages. Its innovative “Cube” hub integrates a wireless gateway, siren, and fob reader into a sleek unit that won’t look out of place on your shelf.
See also: Complete Smart Alarm Starter Packs | Contract-Free Professional Smart Alarms
What Makes It Special
Award-Winning Design
The HESTIA system has been recognised for innovation, picking up nominations for Product Innovation of the Year 2023 and Security Solution of the Year 2024 . That’s impressive credibility at this price point.
Vibration Sensor
Unlike many budget kits that only include contact sensors, HESTIA adds a vibration sensor – perfect for detecting attempted forced entry through windows .
Massive Expandability
Despite its compact size, the system can grow with you. Need more protection? Add up to 96 sensors, including motion detectors and water leak sensors .
Perfect for Renters
The system requires no permanent installation and can be taken with you when you move .
Who Should Buy It
Ideal for: Renters, small flats, award-conscious shoppers, and those wanting maximum expandability in a compact package.
Not ideal for: Homes needing GSM/cellular backup or outdoor sirens.
Eufy Security 5-Piece Home Alarm Kit – The Premium Value Pick (Slightly Over Budget, But Worth It)
The Eufy kit technically exceeds our £100 limit. But it’s worth including because it represents the next step up in quality – and because Eufy frequently offers discounts that bring it closer to budget territory.
See also: Best Compact Smart Alarm UK | 4G Backup Smart Alarms
What Makes It Special
Ecosystem Integration
Eufy isn’t just an alarm – it’s a gateway to a full smart security ecosystem. Add cameras, video doorbells, and outdoor sensors as your budget allows .
No Subscription Fees
Unlike SimpliSafe or Ring, Eufy doesn’t require a monthly fee for full functionality. All features work out of the box .
Excellent App Experience
The Independent’s reviewer praised the Eufy Security app for its clear instructions and intuitive interface . You’re not just buying hardware; you’re buying a polished user experience.
Geofencing
The system can automatically arm when you leave and disarm when you return, based on your phone’s location .
Who Should Buy It
Ideal for: Those willing to stretch their budget for a premium experience, homeowners planning to expand their system over time, and anyone wanting a proven brand with excellent app support.
Not ideal for: Strict budget shoppers who can’t exceed £100.
Ring Alarm 5-Piece Kit – The Ecosystem King (Also Over Budget)
Ring’s 5-Piece Kit is another system that hovers above our budget line but deserves mention as the gold standard for Alexa integration.
See also: Pet-friendly smart alarms | Best Slim contact sensors for windows and doors
What Makes It Special
Alexa Integration
As an Amazon company, Ring works seamlessly with Alexa. View camera feeds on Echo Show, arm/disarm with voice, and receive doorbell announcements .
Assisted Monitoring
Ring doesn’t call the police – instead, it calls your chosen emergency contacts when the alarm triggers. This unique approach gives you control while still providing backup .
Massive Ecosystem
From doorbells to cameras to floodlights, Ring offers everything you need to build a comprehensive security system.
Who Should Buy It
Ideal for: Alexa households, those wanting the largest accessory ecosystem, and shoppers who prioritise brand recognition.
Not ideal for: Strict budget buyers, Google/Apple households, or those wanting no monthly fees.
Amazon UK Availability: ✅ Available
Understanding Your Options – What to Look for in a Budget Alarm
Connectivity Matters
| Type | Pros | Cons |
|---|---|---|
| WiFi-only | Simple, affordable, works with app | Dies if internet goes down |
| WiFi + GSM | Cellular backup keeps working | Higher cost, requires SIM card |
The LWOHSI system’s GSM backup is a standout feature at this price .
Services: Security Installation | CCTV Installation | UK camera installers
Sensor Types
| Sensor | What It Detects | Included In |
|---|---|---|
| Contact sensor | Doors/windows opening | All systems |
| Motion sensor | Movement in rooms | LWOHSI, Eufy, Ring |
| Vibration sensor | Forced entry attempts | HESTIA only |
Siren Volume
| Decibels | How Loud | Systems |
|---|---|---|
| 100dB | Very loud – similar to smoke alarm | Eufy |
| 120dB | Extremely loud – professional grade | LWOHSI |
Subscription vs. No Subscription
The Verdict – Which Budget Alarm Should You Buy?
If you’re looking for the best balance of features, price, and resilience, the LWOHSI WiFi + GSM Alarm is my top pick for most people. The GSM cellular backup means you’re protected even if your internet goes down – a feature usually found on systems costing three times as much. The 120dB siren is genuinely attention‑grabbing, and app control keeps you connected wherever you are.
For renters and small flats, the HESTIA Smart System at just under £60 is a steal. It’s compact, easy to install, and won’t upset your landlord. The included vibration sensor adds an extra layer of protection for windows, and the ability to expand to 96 sensors means it can grow with you.
If you’re willing to stretch your budget, the Eufy 5‑Piece Kit is worth every penny. The app experience is excellent, the hardware feels premium, and the ability to add cameras and doorbells later makes it a long‑term investment.
For Alexa households, Ring is the obvious choice. The Alexa integration is seamless, and the range of compatible devices is unmatched. Just be prepared for subscription costs if you want advanced features.
Whichever you choose, you’re getting proper smart home security for under £100 – something that was almost unthinkable just a few years ago.
Frequently Asked Questions
Q1: Can I really get a decent alarm system for under £100?
A: Absolutely. The LWOHSI and HESTIA systems prove that you don’t need to spend hundreds for reliable protection. While they lack the professional monitoring of premium systems, they provide loud sirens, instant app alerts, and effective deterrence – often enough to send intruders packing .
Q2: Do I need professional monitoring?
A: It depends on your priorities. Professional monitoring (like SimpliSafe offers from £27.90/month) means someone else calls the police if your alarm triggers . Self-monitored systems alert you, and you decide what to do. For many people, a loud siren and phone notification are sufficient deterrents.
Q3: What happens if my internet goes down?
A: With most budget WiFi alarms, you lose connectivity. However, the LWOHSI system includes GSM cellular backup, keeping your system operational even without broadband . This is a significant advantage for those in areas with unreliable internet.
Q4: Are these systems suitable for renters?
A: Yes! All the systems featured use adhesive pads or screws that won’t permanently damage walls. The HESTIA system is particularly well-suited for rentals, with its compact design and no-installation-required approach .
Q5: Can I expand these systems later?
A: Most budget systems are expandable. The HESTIA system supports up to 96 sensors . The LWOHSI system also allows adding more sensors. This means you can start small and build your system over time.
Q6: Do I need a subscription for these alarms?
A: For the LWOHSI, HESTIA, and Eufy systems, no – all features work out of the box with no ongoing costs . Ring requires a subscription for advanced features like video recording and assisted monitoring .
Q7: Will these work with Alexa or Google Assistant?
A: Yes – all featured systems offer voice assistant integration. The LWOHSI system works with Alexa , HESTIA works with both Alexa and Google , Eufy supports both , and Ring naturally integrates deeply with Alexa .
Q8: How loud are the sirens?
A: The LWOHSI system boasts a 120dB siren – extremely loud . Eufy’s built-in siren reaches 100dB . Both are sufficient to alert neighbours and scare off intruders.
Q9: What’s the difference between a contact sensor and a motion sensor?
A: Contact sensors attach to doors and windows, detecting when they open. Motion sensors detect movement within a room. For comprehensive protection, you want both. The Eufy kit includes one motion sensor and two contact sensors , while HESTIA includes two contact sensors and a unique vibration sensor for windows .
Q10: Can I take these systems with me if I move?
A: Absolutely. All these systems are designed for DIY installation and can be easily removed and reinstalled in a new home. The HESTIA system is specifically marketed as perfect for renters .
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- [Off the Grid: 4G Backup smart alarm systems]
