Here is the short answer: for most UK homes the hub matters less than people fear — every current Ajax hub runs the app, the sensors and the sirens properly. Hub 2 Plus earns its step up on larger properties and anything commercial: more devices, more users, faster communication paths. So buy the kit whose sensors match your property, and let that choose your hub — which is exactly how Ajax sells them.
Ajax is the alarm range people ask for by name at the counter now, and the question is always the same: which kit? Behind it sits the hub question — Hub 2 or Hub 2 Plus — and a fear of buying the wrong backbone. Having sold and demonstrated these from Villa Road for years, here is the honest sorting.
1. What the hub actually does
The hub is the brain: every detector, siren and fob enrols to it, it runs the radio, and it carries the alarm out to the world — to your phones, and to professional monitoring if you take it. When the hub is right for the property, you never think about it again. That is the standard to buy to.
2. Hub 2 vs Hub 2 Plus, the differences that matter
Both are proper two-way wireless hubs with photo-verification support. Where the Plus earns its name is headroom: it supports more devices and more users, and adds faster and additional communication paths — the things you notice on a big house, an HMO, or a commercial unit, and generally do not on a three-bed semi. If you are between them at the same money, take the Plus for the headroom; if the Hub 2 kit's sensors fit your property better today, it will not be the thing that lets you down.
3. The kits, compared by property
The KIT2 S on Hub 2 is the classic house package: hub, two MotionProtect S detectors, a DoorProtect S contact, indoor and street sirens, two fobs. For a typical semi or terrace, that is the whole core system in one box.
The same sensor package rides on the bigger brain in the KIT2 S on Hub 2 Plus — and with both kits at the same money in our store as we write, the Plus version is the straightforward pick when you expect the system to grow: outdoor detection, more zones, more users, a commercial future.
The KIT18 S is the step up in sensors rather than just hub: Hub 2 Plus with the Superior range of detectors and a keypad — the specification we point larger homes and small commercial premises at, and the one to choose when a keypad by the door matters to how the household actually arms the thing.
4. Growing the system later
The quiet strength of buying into Ajax is that the kit is a starting eleven, not a sealed box. The devices people actually add, in the order they add them:
- MotionCam Outdoor HighMount — outdoor detection with photos in the alert; the upgrade that changes 3am.
- Curtain Outdoor — the tripwire across the side gate; the full logic is in our perimeter alarms guide.
- FireProtect 2 SB — smoke and heat on the same system and the same app, with a sealed ten-year battery.
Trade tip: enrol every device at the hub's location before final mounting. Ten minutes of bench-enrolling saves the ladder-and-app dance, and you confirm signal from each final position with the device in hand.
Ajax Kits, Summarised
| Property | Kit | Hub inside |
|---|---|---|
| Flat, terrace, typical semi | KIT2 S (Hub 2) | Hub 2 |
| Same home, but you expect to grow it | KIT2 S (Hub 2 Plus) | Hub 2 Plus |
| Larger home, small commercial, keypad wanted | KIT18 S Superior | Hub 2 Plus |
Expert Help in the West Midlands
Villa Road, Birmingham, since 1975. Tell us the property and how you live in it — who arms it, whether there are pets, what the garden is like — and we will pick the kit and the add-ons in one conversation. We keep Ajax working on the counter, so you can hold the devices and see the app before spending anything.
Browse Ajax alarm systems. Get in touch for a spec.
Related reading: are Ajax alarms any good, how to install an Ajax alarm, Ajax door and window sensors, and self-monitoring vs professional monitoring.
Frequently Asked Questions
What is the difference between Ajax Hub 2 and Hub 2 Plus?
Headroom: the Plus supports more devices and users and adds faster and additional communication paths. Both run the app, photo verification and the full device range properly — on a typical home you would struggle to tell them apart in daily use.
Which Ajax kit is best for a normal house?
KIT2 S — hub, two motion detectors, door contact, both sirens and two fobs covers the core of a typical UK home. Take the Hub 2 Plus version if you expect to add outdoor detection or more zones later.
Can I add Ajax devices to the kit later?
Yes — that is the design. Outdoor detectors, fire detection, keypads and more enrol to the same hub and appear in the same app. The one rule: Ajax devices pair with Ajax hubs — wireless alarm protocols never mix between manufacturers.