Kidde 21007584 I4618 Firex Hardwire Ionization Smoke Detector with Battery Backupwhite
- Smoke Detectors & Fire Alarm
- Corded electric
- Ionization
- 1
A sensible replacement pick for a home already wired for interconnected Kidde alarms, given the 24-device interconnect capacity and battery backup.
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How it ranks among the 10 smoke detectors & fire alarms we track
4.3★ across 398 Amazon ratings, Bayesian-smoothed toward the category average.
398 Amazon ratings, weighted on a log scale so huge counts don't drown everything.
1,000+ bought on Amazon last month.
Brand identity, imagery, description and spec coverage.
The ProductDome score is separate from the Amazon rating shown above: it combines the Bayesian-smoothed Amazon rating with evidence volume, tracked demand, and data quality across the 10 smoke detectors & fire alarms we track - how the scorecard works · full smoke detectors & fire alarms data report. Confidence: high - strong rating volume and complete data.Updated 7 days ago. Data-computed, not a hands-on test. Compiled by the ProductDome Research Team.
Overview
The Kidde I4618 (model 21007584) is a hardwired ionization smoke detector with battery backup, built to interconnect with up to 24 compatible smoke, CO and heat alarms across a home.
This is a hardwire, AC/DC direct-wire unit meant to interconnect with other Kidde alarms rather than stand alone, which makes it fit best as a like-for-like replacement in a house already wired for an interconnected system, not as a simple battery-only add-on.
- Hardwired AC/DC power with battery backup
- Interconnects with up to 24 devices (18 initiating)
- Alarm memory LED flags the triggering unit
- Front battery pull tab for access without unmounting
Who it's for
Homeowners replacing a hardwired smoke detector in a house already wired for interconnected alarms. Not a fit for someone who wants a simple standalone battery-only detector with no household wiring involved.
Strengths and trade-offs
Drawn from this product's published specifications.
- Battery backup keeps it working during a power outage
- Interconnects with up to 24 devices for whole-home coverage
- Alarm memory LED flags the unit that triggered first
- Front battery pull tab allows access without unmounting the unit
- No review data available to confirm long-term reliability
- Ionization-only sensing suits fast flaming fires better than smoldering ones
- Hardwiring makes installation less simple than a battery-only unit
Performance notes
Because it wires into AC power with a battery backup, the alarm keeps working through a power outage, and the interconnect wiring triggers every linked smoke, CO or heat alarm at once. An alarm memory LED flashes on whichever unit first detected the alarm condition, which helps identify the source room in a multi-unit system.
Specifications
| Brand | Kidde |
|---|---|
| Model | 21007584 |
| 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 | |
| Unit Count | 1 |
| Warranty & support | |
| Manufacturer Warranty Description | 10 years |
| Other details | |
| Sensor Type | Ionization |
| Number of Items | 1 |
| BuiltIn Media | Alarm(36), Mounting hardware (36), User Manual (36), Wiring harness (36) |
| Mfr Part Number | 21007584 |
| Product Style | Hardwired Smoke Detector |
| Alarm | Audible |
| Item Type Name | Kidde i4618 Firex Hardwire Ionization Smoke Detector with Battery Backup |
Other Kidde smoke detectors & fire alarms
How it compares
This product against the closest alternatives we track in smoke detectors & fire alarms.
| Product | Amazon rating | Ratings | ProductDome score |
|---|---|---|---|
| Kidde 21007584 I4618 Firex Hardwire Ionization Smoke Detector with Battery BackupwhiteThis product | 4.3 / 5 | 398 | 4.2 / 5 |
| First Alert Battery Smoke AlarmFirst Alert | 4.6 / 5 | 5,600 | 4.7 / 5 |
| X-Sense Smoke Detector Carbon Monoxide Detector ComboX-Sense | 4.5 / 5 | 4,200 | 4.5 / 5 |
| First Alert SC-9120B Hardwired Smoke and Carbon Monoxide Alarm with Battery Backup 2 PackFirst Alert | 4.6 / 5 | 574 | 4.5 / 5 |
| First Alert Hardwire Smoke AlarmFirst Alert | 4.5 / 5 | 2,600 | 4.4 / 5 |
Similar smoke detectors & fire alarms from other brands
Questions about the Kidde 21007584
Common buyer questions answered straight from the product spec data - no fluff, no "it depends".
How many devices can the Kidde I4618 interconnect with?
Up to 24 devices total, of which 18 can be initiating alarms, including smoke, CO and heat alarms.
What happens to the Kidde 21007584 during a power outage?
Its battery backup keeps it operating so it isn't disabled when household power drops.
Can I change the battery without removing the Kidde I4618 from its mount?
Yes, a front battery pull tab allows battery activation and access without taking the unit off its mounting bracket.