Kidde Firex I4618 Hardwired Ionization Smoke Detector
- Ionization sensor smoke alarm
- Hardwired with battery backup
- 85 decibel audible alarm
- Interconnects with up to 24 Kidde devices
- 10 year limited warranty
- Wiring harness and mounting hardware included
Last refreshed Sep 8, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A hardwired Kidde Firex smoke alarm that adds a battery backup. The interconnect limits in the listing disagree, and it does not list carbon monoxide sensing.
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ASIN: B008SE0LLIModel: I4618Category: Smoke Detectors & Fire Alarms
Overview
A hallway or bedroom ceiling with existing alarm wiring is the place for this hardwired Kidde Firex detector. It senses smoke with an ionization sensor and has a front-access battery door for the backup battery.
Hardwired power with a battery fallback and interconnect ability suit a home with a wired alarm circuit. The limitation is inconsistent listing detail on how many devices can connect, and a nonsensical weight entry.
Who it's for
A house with alarm wiring already run to the ceiling suits the hardwired design. Shoppers who need carbon monoxide sensing, a wireless unit or photoelectric detection should look at another model.
Pros and cons
- Hardwired with battery backup
- Front-access battery door
- Wiring harness included
- Manufacturer limited warranty
- Interconnect counts disagree
- No carbon monoxide sensing listed
- Weight entry looks wrong
Performance notes
The ionization sensor reacts to smoke particles in the air and the alarm sounds an audible tone. Mains power runs the unit normally, and the backup battery covers a power cut. The interconnect feature lets linked alarms sound together.
Specifications
| Brand | Kidde |
|---|---|
| Model | I4618 |
| Dimensions & fit | |
| Item Weight | 21.6 pounds |
| Capacity & performance | |
| Upper Temperature Rating | 100 °F |
| Power & efficiency | |
| Power Source | Corded Electric |
| Construction & materials | |
| Enclosure Material | Plastic |
| Color | White |
| Compatibility & installation | |
| Compatible Devices | Up to 24 Kidde devices |
| Included components | |
| Included components | Alarm, mounting hardware, user manual, wiring harness |
| Unit Count | 1 Count |
| Warranty & support | |
| Manufacturer Warranty Description | 10 year limited warranty |
| Other details | |
| Sensor Type | Ionization |
| Alarm | Audible |
| Item Type Name | Hardwired smoke detector with battery backup |
| BuiltIn Media | Alarm(36), Mounting hardware (36), User Manual (36), Wiring harness (36) |
| Mfr Part Number | 21007584 |
Closest rivals on specs
First Alert SC9120B Hardwired Smoke and CO Alarm 2 Pack- Item Weight 21.6 vs 1.3 pounds (+1562%)
X-Sense SC07 Smoke and Carbon Monoxide Detector Combo- Item Weight 21.6 vs 1 pounds (+2060%)
First Alert SMICO110 10-Year Smoke and CO Alarm- Item Weight 21.6 vs 0.7 pounds (+2986%)
Frequently asked questions
Is the Kidde Firex i4618 a carbon monoxide alarm too?
No. The listing describes an ionization smoke detector and does not list carbon monoxide sensing.
How many alarms can the Kidde Firex i4618 link together?
The listing is inconsistent: the specs say up to 24 Kidde devices and the description says up to 18 Firex devices. Confirm before planning a system.
What is included with the Kidde Firex i4618?
The listing names the alarm, mounting hardware, a user manual and a wiring harness.