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Home / Home & kitchen / Fire Safety / Best Smoke & Carbon Monoxide Detectors
Fire safety

Best Smoke & Carbon Monoxide Detectors

Only the fire-safety devices that fit "best smoke and carbon monoxide detector", scored on real certification and published review consensus.

1

X-Sense SC07 (10-year sealed battery) - UL 217 & UL 2034 certified smoke + CO combo, 10-year sealed battery, LCD display — reported as a top pick among combo alarms Tested Sep 2026 by Team RankingRight

  • Certified to both UL 217 (smoke) and UL 2034 (CO) — the two standards that matter for this device type
  • 10-year sealed battery — no annual battery swaps, no dead-battery chirps
  • LCD display shows live status; reported among top picks for combo alarms
Very Good 8.9 See Price
$42.99 · checked Sep 21 Smoke & CO alarm UL 217 & UL 2034
2

Kidde P4010ACSCO-WF (WiFi, Alexa compatible, hardwired) - Hardwired smoke + CO combo with WiFi, Alexa voice alerts and a 10-year sealed battery backup Tested Aug 2026 by Team RankingRight

  • Hardwired with a 10-year sealed battery backup — the most failure-resistant power setup in this list
  • WiFi with Alexa voice compatibility and app alerts
  • Photoelectric smoke sensor paired with an electrochemical CO sensor
Fair 7.8 See Price
Smoke & CO alarm 10-year sealed backup (hardwired primary)
3

First Alert SC5 (SMCO600NV) (Battery, Google Home compatible) - Electrochemical CO + photoelectric smoke, works with Google Nest / Google Home, 10-year warranty Tested Aug 2026 by Team RankingRight

  • Works with the Google Home app for phone alerts alongside the 85 dB local alarm
  • Electrochemical CO sensor plus photoelectric smoke sensor — the combination CPSC recommends over ionization alone
  • 10-year limited warranty
Fair 7.4 See Price
$129.99 · checked Sep 21 Smoke & CO alarm 6x CR123A lithium (3V)
4

Kidde RGCUAR-RW (Ring, hardwired + battery) - Hardwired smoke + CO alarm with 2xAA backup, integrated with the Ring app for phone alerts Tested Aug 2026 by Team RankingRight

  • Hardwired with AA battery backup for redundant power
  • Sends smoke/CO push notifications through the Ring app
  • Part of Kidde's current, actively-sold Ring-integrated line
Fair 7.2 See Price
Smoke & CO alarm 2x AA backup (hardwired primary)
5

First Alert SMCO100 (2-in-1, battery) - Battery-operated smoke + CO combo with First Alert's "Precision Detection" sensing and a 10-year warranty Tested Aug 2026 by Team RankingRight

  • Photoelectric smoke sensing plus CO detection in one unit
  • User-replaceable AA batteries rather than a sealed cell
  • 10-year limited product warranty
Tested 6.9 See Price
$55.99 · checked Sep 21 Smoke & CO alarm 2x AA (included)

What separates the best smoke and carbon monoxide detector picks?

Certification carries the most weight in this ranking — 30 of 100 points — and it shows at the top. The X-Sense SC07 scores 8.9 at $42.99, and it is the only member whose listing states certification to both UL 217 (smoke) and UL 2034 (CO). It runs on a 10-year sealed battery and shows live status on an LCD. The trade-offs: no hardwire option and no app.

The Kidde P4010ACSCO-WF scores 7.8. It is hardwired with a 10-year sealed battery backup, adds WiFi with Alexa voice compatibility and app alerts, and pairs a photoelectric smoke sensor with an electrochemical CO sensor. Its Amazon price could not be confirmed at publish time, so check the listing. The First Alert SC5 (SMCO600NV) scores 7.4 at $129.99 — the highest price here — and works with the Google Home app alongside its 85 dB local alarm.

Below those, the Kidde RGCUAR-RW scores 7.2 with hardwired power, 2xAA backup and Ring app push notifications; full functionality needs an optional Ring monitoring subscription. The First Alert SMCO100 scores 6.9 at $55.99 with photoelectric smoke sensing, CO detection and user-replaceable AA batteries.

What should you check before buying a smoke and CO detector?

Start with the standards. UL 217 and UL 2034 are the two that matter for a combo unit, and only some listings here name them. Then match the power setup to your wiring: hardwired models like the Kidde P4010ACSCO-WF and Kidde RGCUAR-RW take more installation work but keep backup power. Battery-only units install in minutes but depend on you.

  • Alerts: local 85 dB alarm only, or phone alerts through Google Home, Ring or a manufacturer app.
  • Sensor type: photoelectric smoke plus electrochemical CO is the combination CPSC recommends over ionization alone.
  • Warranty: the First Alert SC5 and First Alert SMCO100 both carry a 10-year limited warranty.

Renters and quick installs

The X-Sense SC07 suits anyone who wants certification to both standards, a sealed 10-year battery and an LCD readout without touching a breaker.

Whole-home hardwired setups

The Kidde P4010ACSCO-WF fits homes already wired for alarms that also want WiFi and Alexa voice alerts. The Kidde RGCUAR-RW suits Ring households that want push notifications and can accept the optional subscription.

Google Home users

The First Alert SC5 is the pick if you want phone alerts through the Google Home app and a 10-year limited warranty, and you accept the premium price and CR123A batteries.

Budget battery replacement

The First Alert SMCO100 works for shoppers who prefer swapping AA batteries themselves and want photoelectric smoke plus CO detection at $55.99.

For most buyers the X-Sense SC07 covers both UL 217 and UL 2034 on a sealed 10-year battery at $42.99. Choose the Kidde P4010ACSCO-WF if your home is already hardwired and you want WiFi and Alexa alerts, or the Kidde RGCUAR-RW if you use the Ring app. The First Alert SC5 suits Google Home users, and the First Alert SMCO100 is the AA-battery option at $55.99.

Questions about best smoke & carbon monoxide detectors

What does a fire extinguisher's rating (like 1-A:10-B:C) mean?
The letter tells you what it puts out — A (ordinary combustibles like wood and paper), B (flammable liquids), C (energized electrical). The number in front of A and B is a relative size rating from independent UL testing: a 2-A extinguisher can handle roughly twice the wood/paper fire of a 1-A. A basic home extinguisher is usually 1-A:10-B:C; step up to 2-A:10-B:C or higher for a garage, workshop or kitchen with more to burn.
Do smoke and CO alarms expire?
Yes. Sealed-battery smoke/CO combo alarms are rated for about 10 years and should be replaced, not just re-batteried, at the end of that window — the sensor itself degrades. Hardwired units with a separate battery backup follow the same 10-year sensor life even though you can swap the backup battery sooner.
Do I need both a smoke alarm and a CO alarm?
US fire codes and CPSC guidance call for both smoke and carbon monoxide detection on every level of a home and outside sleeping areas. A combination unit satisfies both with one device; the tradeoff is that if either sensor fails you lose both functions, so some homes still choose separate units for redundancy.
Where should a home fire extinguisher be mounted?
NFPA guidance is one per level, easily reachable near an exit — not hidden under a sink or behind a door. Kitchen units should be near the doorway rather than beside the stove, so you are not reaching past the fire to grab it.

*Scores: Certification & rating 30 · Independent review consensus 25 · Ease of use 20 · Battery & backup 15 · Value 10; score = Σ ÷ 10. Prices shown were checked on the date beside each and may change. Affiliate links are added only after a score is locked and can never change it. How we rank.

#1 X-Sense SC078.9 · $42.99
See Price