Smoke Detectors
First Alert SC5 Alternatives
The SC5 does four things at once: smoke, CO, voice and phone alerts. Decide which of those you actually need and the price falls by two thirds.
By Ryder M.Last reviewed
If what you want from the SC5 is smoke and CO in one sealed unit with a readable display, buy the X-Sense SC07 - it does that for roughly a third of the price, and it is also the budget pick here. If what you want is alarms that all sound together across a house with no alarm wiring, the X-Sense SC07-W adds a wireless interconnect between units and still costs a fraction of one SC5. And if you specifically need a smart alarm a controller can see, the First Alert SMCO410 is Z-Wave Plus certified, which is what lets a Ring base station or a Z-Wave JS setup adopt it. What none of these replaces is the SC5's one unique property: Google promotes it as the Nest Protect replacement, it mounts on the same bracket, and it interconnects with compatible Nest Protect units - so a staged changeover is a reason to pay the premium.
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Decide which SC5 feature you are actually buying
The SC5 bundles four things, and almost nobody needs all four. Certified detection of smoke and carbon monoxide is the cheapest of them and is available for a third of the price. Wireless interconnection - alarms that all sound together - is the one with the strongest safety argument, and it is available separately for a fraction of the cost. Voice annunciation that names the hazard is genuinely useful on a combination alarm, and available on cheaper units elsewhere on this site. Phone alerts through an app are the only feature with no cheap equivalent here, and they matter most for a house that is empty.
So the honest way to shop against the SC5 is to rank those four. If you are protecting an occupied family home with no alarm wiring, interconnection beats the app and the X-Sense SC07-W is the better buy at a fraction of the price. If you are covering a second home or a rental you are not in, the app is the point and the premium is defensible.
There is one job only the SC5 does, and it is worth stating plainly because it is the reason the product exists: Google promotes it as the Nest Protect replacement, it mounts on the same bracket, and it interconnects with compatible Nest Protect units. That means a household with five Nest Protects can change them one at a time instead of all at once, keeping a working interconnected system throughout. No alternative on this page can do that, and if it is your situation the SC5 is the right purchase.
The last consideration is batteries. The SC5 runs on six replaceable CR123A lithium cells; every alternative here except the SMCO410's sibling range uses a sealed ten-year cell. Over a decade that is a real difference in both cost and the chance of an alarm being left flat.
Quick picks
Scored against covers the sc5's core job, price, ten-year upkeep, smart features and install simplicity. Tap a row for the full write-up. The price in each buy button is the live Amazon price at the last check, stamped with the date it was taken.
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 |  X-Sense SC07 Smoke & Carbon Monoxide Alarm Smoke and CO certified, sealed for ten years, with the CO concentration on a display. The SC5's detection without the app, at roughly a third of the price. | The budget pick - the SC5's core job, minus the smart layer | 8.9/ 10 | |
| 2 |  X-Sense SC07-W Wireless Interconnected Smoke & CO Alarm The same certified smoke and CO alarm with a wireless link between units, so one alarm sounds and the whole set sounds. The SC5's most valuable feature, far cheaper. | A whole house with no alarm wiring - interconnect without the SC5 price | 9.0/ 10 | |
| 3 |  First Alert SMCO410 Z-Wave Plus Smart Smoke & CO Alarm Z-Wave Plus certified smoke and CO alarm with a sealed ten-year cell. The route to a monitored alarm without the SC5's price or its app ecosystem. | A smart home - the alternative a controller can actually see | 8.7/ 10 | $64.98 · View on Amazon #ad how we are funded · price as of November 11, 2026 |
The picks
1. The budget pick - the SC5's core job, minus the smart layer
X-Sense SC07 Smoke & Carbon Monoxide Alarm
Smoke and CO certified, sealed for ten years, with the CO concentration on a display. The SC5's detection without the app, at roughly a third of the price.
- Listed to
- UL 217 and UL 2034
- Sensing / agent
- Photoelectric smoke sensing plus an electrochemical CO cell
- Power / service life
- 10-year sealed lithium battery, not hardwired
What the SC5 is known for, fairly stated. It is the alarm Google points Nest Protect owners toward: photoelectric smoke sensing plus an electrochemical CO cell, voice alerts with a Heads-Up warning that names the hazard and location, phone alerts through the Resideo Connect app, wireless interconnect including with compatible Nest Protect units, and 85 dB at 10 ft. It mounts on the Nest Protect bracket, which is a genuinely thoughtful detail.
Which of those you are paying for. Detection is the cheapest part. Three of the four headline features - voice, app, interconnect - are convenience and coverage, and two of the three are available separately for far less. This pick strips all of them and keeps the certified detection plus a display.
Where that is the right trade. A single alarm in an occupied home, where somebody is there to hear it. Away-from-home notification matters for a second home, a rental or a long absence; in a house with people in it, the horn is the notification.
What it does well
- **Certified to UL 217 and UL 2034** - the same two hazards the SC5 covers, from one ceiling position
- **Photoelectric smoke sensing named on the listing**, which the SC5's own page does not state as plainly
- **LCD shows the measured CO concentration**, so you get a number without opening an app
- **Sealed 10-year lithium cell** with no battery ritual - the SC5 uses six replaceable CR123A cells
- **Roughly a third of the SC5's price** at the time of writing, which is the whole argument
- No account, no app, no cloud dependency - it works when the internet does not
The downside
- **No phone alerts.** If the house empties out for weeks, nothing tells you the alarm sounded. That is the SC5 feature you are giving up
- **No voice annunciation**, so it sounds a horn rather than naming the hazard
- **No interconnect at all**, and no Nest Protect compatibility
- **ETL to UL 217 rather than UL-listed** - same standard, different mark
- Small unlit display
Do not buy this if: a household replacing Nest Protect units in stages, or anyone who bought the SC5 specifically for away-from-home notifications. For the Nest changeover see [Nest Protect discontinued: what to buy](/smoke-detectors/nest-protect-discontinued-what-to-buy).
- LCD reads the measured CO concentration rather than only alarming
- Standalone unit — no wireless interconnect, no Wi-Fi, no base station
- Sealed battery, so there is no annual battery ritual and no low-battery chirp until end of life
- Test and silence on one control
2. A whole house with no alarm wiring - interconnect without the SC5 price
X-Sense SC07-W Wireless Interconnected Smoke & CO Alarm
The same certified smoke and CO alarm with a wireless link between units, so one alarm sounds and the whole set sounds. The SC5's most valuable feature, far cheaper.
- Listed to
- UL 217 and UL 2034
- Sensing / agent
- Photoelectric smoke sensing plus an electrochemical CO cell
- Power / service life
- 10-year sealed lithium battery, not hardwired
Interconnection is the SC5 feature worth replicating. Of everything the SC5 does, the one with a real safety argument behind it is that its alarms sound together: that is the mechanism that gets a sleeping person out of a back bedroom with the door shut. Phone alerts are useful when you are out; interconnection is what matters when you are in.
Why wireless rather than wired. Pulling alarm cable through finished ceilings is an electrician's invoice that dwarfs the alarms. Radio gets the same functional outcome for the price of the units, which is the entire reason this product class exists.
Buy the set in one order and pair before mounting. Discovering a range problem after the holes are drilled is the one avoidable mistake with these.
What it does well
- **Wireless interconnect for up to 24 units** - one alarm triggers the whole set, which in a house with bedrooms upstairs is worth more than every app feature combined
- **Smoke and CO certified** to UL 217 and UL 2034, with the photoelectric sensor named on the listing
- **Radio between the alarms, not Wi-Fi.** No router, no account, no cloud - if the internet is down they still sound together
- **Sealed 10-year lithium cell** in every unit, no wiring and no hub
- **LCD CO reading on each unit**
- X-Sense recommends it specifically for large or multi-story homes
The downside
- **The real entry price is at least double**, because one interconnect alarm on its own is just a more expensive SC07
- **Range is decided by your house.** Masonry, foil-backed insulation and steel cut the link, so pair the set and test it in the real positions before drilling
- **No phone alerts and no voice**
- **It will not join a hardwired loop** or interconnect with Nest Protect
- ETL to UL 217 rather than UL-listed, like the rest of the X-Sense range
Do not buy this if: a studio or single-floor flat, where there is nothing to interconnect and the plain SC07 does the job for less. [Interconnected smoke alarms](/smoke-detectors/interconnected-smoke-alarms) covers the wired alternative.
- Wireless interconnect for up to 24 units — one alarm triggers the whole set
- No wiring, which is the point: it retrofits interconnection into a house that never had it
- LCD CO reading on each unit
- X-Sense recommends it for large or multi-story homes
3. A smart home - the alternative a controller can actually see
First Alert SMCO410 Z-Wave Plus Smart Smoke & CO Alarm
Z-Wave Plus certified smoke and CO alarm with a sealed ten-year cell. The route to a monitored alarm without the SC5's price or its app ecosystem.
- Listed to
- First Alert states the alarm's Precision Detection sensing complies with the latest industry standards; it does not name a UL edition on the listing
- Sensing / agent
- Photoelectric smoke sensing plus an electrochemical CO cell
- Power / service life
- Sealed 10-year lithium battery
Two different ideas of smart. The SC5 is cloud-first: a vendor app, a vendor account, notifications through Resideo Connect. This alarm is protocol-first: Z-Wave Plus, adopted by whatever controller you run, with the automation logic on your own hardware. Neither is better in the abstract; they suit different households, and the second one survives a vendor losing interest.
Read the Ring requirement carefully. First Alert states that away-from-home notification needs a Ring Alarm or Ring Alarm Pro base station plus a Ring Alarm Smoke and CO Listener. If you are buying this expecting phone alerts out of the box, that is the sentence to plan around.
It is still a certified alarm first. Whatever the hub does, this unit has to detect smoke and carbon monoxide on its own, and it is built to do that - which is the right order of priorities for a device on a ceiling.
What it does well
- **Z-Wave Plus certified**, which is what lets a non-Ring controller such as Home Assistant's Z-Wave JS adopt it as a native device
- **Works with a Ring Alarm or Ring Alarm Pro base station** - First Alert states the base station plus a Ring Alarm Smoke and CO Listener are required for away-from-home notifications
- **Smoke and CO in one unit**, with First Alert's Precision Detection sensing stated to reduce cooking nuisance alarms
- **Sealed 10-year lithium cell**: no battery changes and no low-battery chirps, where the SC5 uses six replaceable CR123A cells
- **Local control via Z-Wave** rather than a vendor cloud, which is the opposite trade from the SC5's app
- Test and silence button with an end-of-life warning
The downside
- **Needs a Z-Wave controller or a Ring base station to be smart at all.** On its own it is a good sealed combination alarm with no notifications
- **Away-from-home alerts require specific additional Ring hardware** per First Alert's own statement, which is an extra purchase and an extra point of failure
- **No voice annunciation** and no display
- **First Alert does not name the sensor type** - "Precision Detection" is the published wording
- More expensive than the X-Sense units for a feature set that only pays off inside a smart-home stack
Do not buy this if: a household with no hub and no intention of getting one, where the money is better spent on more certified alarms. [Smart versus regular smoke detectors](/smoke-detectors/smart-vs-regular-smoke-detectors) works through where that line sits.
- Z-Wave Plus certified, which is what lets a non-Ring controller such as Home Assistant's Z-Wave JS adopt it
- Works with a Ring Alarm or Ring Alarm Pro base station — First Alert states the base station plus a Ring Alarm Smoke and CO Listener are required for away-from-home notifications
- Precision Detection sensing, which First Alert states reduces cooking nuisance alarms
- Test and silence button, plus an end-of-life warning when it is time to replace the unit
- Sealed ten-year cell: no battery changes and no low-battery chirps
First Alert product documentation
#ad how we are funded · price as of November 11, 2026
The SC5 against the alternatives
Published specifications only, checked on 2026-11-10. The live price and the date it was taken sit in each buy button - the SC5's own price appears on its review page.
| Alarm | Smoke + CO | Interconnect | Phone alerts | Power | Nest Protect compatible |
|---|---|---|---|---|---|
| First Alert SC5 (the original) | Yes | Wireless, incl. Nest Protect | Yes, Resideo Connect | Six CR123A cells | Yes |
| X-Sense SC07 | Yes | None | No | Sealed 10-year | No |
| X-Sense SC07-W | Yes | Wireless, up to 24 units | No | Sealed 10-year | No |
| First Alert SMCO410 | Yes | Via Z-Wave controller | Only with specific Ring hardware | Sealed 10-year | No |
The last column is the SC5's moat. If you are replacing Nest Protect units in stages, nothing else here keeps the existing set interconnected while you do it.
Questions people actually ask
What is a cheaper alternative to the First Alert SC5?
Is the First Alert SC5 worth the money?
What alarm can replace a Nest Protect?
Do I need a smart smoke alarm at all?
Does the First Alert SMCO410 work without Ring?
How these picks were chosen. On published specifications, safety listings and manufacturer documentation — plus the findings of organizations that do run tests. We have no laboratory and we do not burn anything. Read the full methodology.
Sources
- UL Solutions — UL 217 — smoke alarms
- UL Solutions — UL 2034 — single and multiple station carbon monoxide alarms
- X-Sense — SC07 10-year battery combination smoke and carbon monoxide alarm with LCD
- First Alert — Nest Protect replacement — First Alert SC5 compatibility
- NFPA — NFPA 72, National Fire Alarm and Signaling Code (2025 edition)
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