This article was machine-translated from French and is being reviewed. Prices are in Algerian dinars excl. VAT.
Wireless smoke detector: the Ajax FireProtect Plus adds a temperature sensor and an CO sensor, and is used within the Ajax ecosystem (hub and app), at 23,500 DA HT (price on asloitech.com shop as of 06/11/2026, subject to availability), out of stock on that date. The Dahua HY‑SA21A‑W2 belongs to the Dahua wireless alarm range; it costs 14,000 DA HT and was in stock on that date. Both are suitable for a home or small premises. Neither replaces a fire‑safety system in a public‑access building (ERP) or a clinic.
In short
- Ajax FireProtect Plus: 23,500 DA HT, out of stock as of 06/11/2026. It is controlled via the Ajax app.
- Dahua HY‑SA21A‑W2: 14,000 DA HT, in stock as of 06/11/2026, i.e. 9,500 DA HT less than the Ajax (23,500 − 14,000).
- For a dwelling or small premises, a wireless detector is useful protection. For an ERP or clinic, it does not replace the control panel, zones, or evacuation alarm.
Wireless smoke detector: the two models in the store
| Ajax FireProtect Plus | Dahua HY‑SA21A‑W2 | |
|---|---|---|
| Store designation | Wireless Fire Detector with Temperature and Carbon Oxide Sensors | Wireless Smoke Alarm |
| Price excl. VAT (06/11/2026) | 23,500 DA excl. VAT | 14,000 DA excl. VAT |
| Availability (06/11/2026) | out of stock | in stock |
| Sensors (manufacturers) | smoke (optical), temperature, carbon monoxide | smoke (photoelectric) |
| Built‑in siren (manufacturers) | 85 dB | 85 to 90 dB(A) at 3 m |
| Power (manufacturers) | batteries, up to 4 years claimed | CR123A battery, 3 years claimed |
| Ecosystem | hub and Ajax app | Dahua wireless alarm range |
The specifications of this table come from the manufacturers’ pages, not the shop sheet. The FireProtect Plus datasheet and the HY‑SA21A‑W2 datasheet give the shop details. The Ajax CO sensor monitors a different risk than smoke; the shop listing mentions it.
Ecosystem: hub, app and sirens
Each detector has its own siren: it sounds on site when smoke is detected. The hub, the small control panel that receives radio signals, adds notifications to the phone and links with other devices. Therefore choose the ecosystem before the detector: motion, door‑opening or flood detectors from the same brand connect to the same hub.
Ajax. Ajax indicates that the FireProtect Plus works with its hubs. The store offers the Hub 2 Plus for 78,000 DA HT, in stock as of 06/11/2026. It also offers the Ajax StreetSiren (outdoor siren) for 32,000 DA HT, in stock as of 06/11/2026.
Dahua. The store offers two alarm kits with hub and outdoor siren (ART-ARC3000H-03-GW2 for 55,000 DA HT and DH-ART-ARC3800H-03-FW2+ARA13-W2 for 75,000 DA HT), as well as wireless sirens ARA12-W2 (indoor, 11,000 DA HT) and ARA13-W2 (outdoor, 18,000 DA HT), all in stock as of 06/11/2026. The HY-SA21A-W2 is available from Dahua in 433 MHz and 868 MHz versions; the store sheet does not specify which is sold. We have not confirmed that this detector connects to either kit: ask before ordering, specifying the hub’s frequency band.
To gauge price levels, two motion detectors of the same function: Ajax MotionProtect at 15,000 DA excl. VAT, Dahua ARD1233-W2 at 8,500 DA excl. VAT, both in stock on 06/11/2026. The difference is 15,000 − 8,500 = 6,500 DA excl. VAT per detector.
Suitable uses: home and small premises
A wireless smoke detector is suitable for an apartment, villa, small shop, office or workshop: no cable to run, quick install, phone notification. It runs on battery, making it less dependent on power cuts. Dahua states that an HY-SA21A-W2 covers 20–40 m² under a ceiling less than 8 m, for indoor use.
Limitations: not a fire safety system for an ERP.
Its technical limits first:
- The radio range depends on walls and floors. Manufacturers advertise up to 1,300 m (Ajax) and 1,000 m (Dahua), but in free field.
- The hub and internet connection must remain available to send notifications.
- The battery is monitored and replaced; heat drains it faster.
- A detector monitors only the room it is in: multiple rooms require multiple detectors.
The main limit lies in the product’s nature. A wireless smoke detector is not a substitute for a fire safety system in an ERP or clinic. It is an autonomous alarm with built‑in siren: Dahua states that the HY-SA21A-W2 meets EN 14604, the standard for smoke alarms intended for residential use. It does not replace the control panel, zone segmentation, manual triggers, evacuation alarm, or testing and maintenance of a complete system. The requirements for your facility are confirmed with the Civil Protection and the inspection office. For these buildings, read our guide on fire detection in clinics or ERPs and the one on conventional or addressable detection.
Frequently asked questions
Is a hub needed with a wireless detector?
For it to sound on site, no: each detector has its own siren. For phone notifications and linking with other devices, yes: the hub receives signals from detectors and relays them to the app. Verify detector compatibility with the hub before buying.
How many detectors are needed for a dwelling?
It depends on the plan and the manufacturer’s instructions. For calculation, at the listed price as of 06/11/2026: 3 Ajax FireProtect Plus detectors cost 3 × 23,500 = 70,500 DA HT (product out of stock at that date), 3 Dahua HY‑SA21A‑W2 detectors cost 3 × 14,000 = 42,000 DA HT. The hub and any siren are added, e.g., the Ajax Hub 2 Plus at 78,000 DA HT.
What happens in a power outage?
Battery‑powered detectors continue to monitor and sound on site. Phone notifications generally require a powered hub and an internet connection. An additional wireless siren alerts in another part of the building.
To equip a dwelling or small premises, or to study a complete system for an ERP, discover our alarm, intrusion and fire solution or the Alarm and Fire category in the online shop.