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First Alert

First Alert SC5 Hardwire Smart Smoke & Carbon Monoxide Alarm

Based on 767 reviews
Condition: New
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$128.88
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Arrives Monday, Nov 16
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At a glance

Condition
New
Style
Hardwired
Model
SMCO600NV-AC
Dimensions
5.75"D x 1.6"W x 5.75"H
Weight
16 oz
Color
White
Power Source
Corded Electric

Features 8

  • Compatible with Google's Nest Protect Alarm
  • Sends alerts to your phone if smoke and CO are detected through the First Alert app
  • Interconnect so when one alarm sounds, all compatible alarms in the home sound
  • Battery backup provides continuous protection during power outages

Description

The fire safety you trust is now connected and compatible. Add smart fire safety alerts to your home with the First Alert SC5 Hardwire Smart Smoke and Carbon Monoxide (CO) Alarm. This 2-in-1 device elevates your home’s fire and CO safety whether home or away.

Specs 18

Brand First Alert
Style Hardwired
Power Source Corded Electric
Color White
Product Dimensions 5.75"D x 1.6"W x 5.75"H
Item Weight 16 ounces
Alarm Audible
Unit Count 1 Count

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Top Amazon Reviews

Regret Purchase: False Alarms, Smart Feature Issues, and Design Concerns
Style: Hardwired
I replaced 9 Nest smoke/CO detectors that were reaching end-of-life with these newer UL 9th edition units. While the underlying detection standards may be improved, the overall experience has been disappointing. MAJOR ISSUES: 1) Defective unit out of the box: One detector repeatedly failed interconnect testing. It initially reported success, then began announcing errors every minute. Factory resets did not resolve the issue. 2) Unreliable app reporting: After installing the remaining units, interconnect testing via the app consistently failed. The system reported that one or more detectors didn’t respond, but the “missing” unit changed each time. The alarms themselves appeared to work, but the cloud reporting is unreliable, which undermines a key purpose of these devices. 3) Poor removal design: Disconnecting the unit requires a flathead screwdriver while also holding the detector and pulling the connector. This is unnecessarily awkward compared to Nest’s simple release mechanism. DESIGN DRAWBACKS VS. NEST: A) No tactile feedback on the main button B) No Pathlight feature C) Voice alerts are less clear D) No apparent microphone for automated self-testing I have not personally experienced false alarms, but given the defective unit, inconsistent app reporting, and similar complaints from other users, I have concerns about long-term reliability. If you want smartphone alerts for hardwired detectors, options are limited. This model avoids a subscription, which is a plus, but reliability should come first, and right now that remains questionable. Updated Note: March 25, 2026 The defective unit’s battery was extremely difficult to remove. It could not be disconnected without first removing the battery, which was wedged in so tightly that I had to use a tool, tearing the battery plastic wrap in the process. Between the battery connection and the AC connector design, this feels like a clear usability failure. It’s hard to understand how this passed basic design review. Updated Note: April 3, 2026 On April 2, one detector dropped off the network and remained offline for the entire day. It repeatedly attempted to reconnect and failed. Per the manufacturer’s app, the unit will still sound locally in a smoke or CO emergency even when it is offline. However, when a device shows no internet connection, there is no way to verify system status remotely, which defeats a primary reason for buying a connected safety device. I tried Bluetooth reconnection, multiple manufacturer resets, full power cycling (AC and battery), and rebooting the mesh. None of it worked. My concern was based on prior experience. Another unit had repeatedly announced a device error every minute. With this detector offline, I had no confidence it would remain stable and not begin the same behavior overnight. What made this worse is that once I removed the device and performed a factory reset, I could not add it back into the app without restoring internet connectivity. That leaves you stuck: you cannot stabilize the device in the app because it is offline, and you cannot bring it back online without additional troubleshooting. What finally resolved the issue was isolating the mesh nodes and rebooting the modem. That is an unreasonable level of troubleshooting for a single device failure. During this entire time, every other detector and smart device in my home remained fully connected and stable. This took two hours to resolve. At this point, this is a one-star product. Had I known I would encounter these issues, I would have installed standard hardwired smoke/CO detectors with voice alerts and possibly added a separate listener device. I regret buying these. Updated Note: June 13, 2026 Since posting my earlier updates, I have now experienced 3 alarm activations from the detector installed in my master bedroom. Based on what I observed at the time, I could not identify an obvious cause for the activations. [Note added on July 16, 2026: 5 hours before the detector went into alarm mode, I did some painting downstairs with low VOC latex paint. The master bedroom is upstairs. I do not believe the painting caused the detector to go into alarm mode, but I am mentioning it because it happened earlier the same day.] The alarm activated 2 nights ago at 11:55 PM, again at 12:04 AM, and again at 12:07 AM. According to the app history, all 3 events originated from the same detector. There was no smoke, cooking activity, steam, or any other obvious condition present that I observed that would explain why the alarm activated. I completely deactivated the detector, battery and AC. These detectors are only about 3 months old. Fortunately I was home when this happened. What concerns me most is that I have a pet at home. A prolonged alarm event would be extremely stressful for a pet left alone in the home. I removed all the First Alert smoke alarms and replaced them with a different brand that integrates with Ring for app notifications. I plan to contact First Alert regarding the master bedroom smoke alarm, which appears to be defective, and request a replacement unit under warranty. Because the original alarms cannot be returned, I will save them as backup units and may be reconsidered for future use if the replacement smoke alarms present problems. Updated Note: June 15, 2026 I contacted Resideo regarding the false alarm issue, and to their credit they promptly agreed to send a replacement unit under their 10-year warranty. Customer support answered immediately without any hold time, which was a pleasant surprise. I was expecting a long wait, but within minutes a replacement unit was being shipped. Because of that level of customer service, I am increasing my rating from 1 star to 2 stars. If I did not have a pet at home, I would likely give these alarms another chance. However, after experiencing multiple false alarm events from a single smoke detector and removing all 9 units from service, I am not comfortable reinstalling them at this time. My concern is the possibility of another false alarm occurring while I am away from home for an extended period. For now, I have replaced them with a different brand and will see how those perform. Updated Note: July 31, 2026 Upon further reflection, I am lowering my rating from 2 stars back to 1 star because I would not buy these detectors again, nor would I recommend them to anyone. Although Resideo provided excellent warranty service and promptly replaced the defective unit, customer service cannot compensate for my lack of confidence in the product. I have since replaced all nine detectors with another brand. Because they cannot be returned, I am out over $1,000, and they are now sitting in my garage. I do not trust them enough to reinstall them, but I am reluctant to discard them in case a future firmware update or other action by the manufacturer addresses the issues I experienced. Based on my experience, I recommend considering other options. ... show more
Reviewed in the United States on March 19, 2026 by S. Simon
Nice Replacement for Nest
Style: Hardwired
Review Image by G. Gibson
I also had a Google Nest that ran out of time. In spite of the negative reviews I bought this alarm as it was easy to install using my existing Nest mount. I have had even less issues with it going off during cooking than even my old Nest. I do only have one installed so there isn’t the pairing issue folks had. I can recommend this to anyone whose Nest is out of time. I do miss the night light. ... show more
Reviewed in the United States on September 15, 2026 by G. Gibson
Downgrade from Nest Protects, DO NOT BUY!!!
Style: Hardwired
My Nest Protects have started to reach their 10 year lifespan and needed to be replaced. Google recommended this as a replacement so decided to get some. Currently have 3 of these. Initial set up is simple and straight forward as these are compatible with the mounting hardware of my Nest Protects. Then the trouble began. My wife and daughter had a cold so we set up a humidifier to help them breath while they slept. 2am the smoke detector went off. No smoke rising warning like I have set up in the setting just straight to full alert. Course since they are all connected every smoke detector goes off. After it turned itself off I started getting messages that the smoke detector had a fault. No trouble shooting tips or anything from the app. The support number in the app to call for help doesn't go to the right department so they have to give you the number to call. FirstAlert said they didn't know what the issue was and offered to replace the unit. A couple months goes by and as my family is getting ready in the morning the smoke detector goes off again in our Master Bedroom. No humidifier, no smoke, no steam, nothing. It blared for about 30 seconds and turned itself off like nothing ever happened. Will have to reach out to support again to see if they can figure out what happened or if I will need yet another replacement. Normally a false alarm or two in any other device wouldn't be a big deal; but this device's sole purpose is to tell me if there is a potential fire or not. Luckily we were home and able to determine that each time was a false alarm but if we were not home what would we do? Have to call the fire department to check things out for us? It just rubs me the wrong way that these devices have failed twice and not something I can recommended purchasing at this time. Especially for the price. Update 5/18/26: If I could give 0 starts I would. My replacement went off again twice yesterday. Once in the evening while we were sitting in the room watching tv and obviously no smoke around and then again at 5am while my whole family was dead asleep. Finally went up to the ceiling and ripped the thing off and yanked the battery out to finally make it stop. It is completely unacceptable to have this many false alarms within a 6 month period. Shame on First Alert for putting out such a horrible product and shame on Google for recommending this product as a replacement for the Nest Protects. Had protects for 10 years and never had a false alarm. In less than a year I have already had 4 false alarms. DO NOT BUY!!!! ... show more
Reviewed in the United States on December 19, 2025 by Colby Plante
The alarms that cried wolf...
Style: Hardwired
Fortunately, the company is taking back all 16 alarms we ordered and installed, so that's good. But these have been a NIGHTMARE. In eleven different instances over the six months since installation, often in the middle of the night, the alarms went off. No fire or smoke, but treated as a fire: "FIRE DETECTED! EVACUATE IMMEDIATELY! CALL 911 !" After a few minutes of sheer terror as we race around looking for the fire, the alarms suddenly stop screaming at us...sometimes. And sometimes they start screaming again. But eventually they go back to sleep. The offending device varied over the six months. The 11 false alarms were triggered by five different devices. When triggered, all 16 alarms scream at the same deafening level. Important info: We chose these because of the app. But the app is not useful. (1) We were unable to turn off the alarms using the app since the units thought there was an actual fire, and therefore the "disarm" button in the app is automatically disabled, with no way to override it except to remove the device from the ceiling and drown it in the swimming pool. Imagine waking to 16 alarms blaring throughout the house, frantically searching for the source and being unable to do anything even if the offending device is identified. Getting a ladder and physically turning off the offending alarm only works for about 3-5 seconds. Then it starts screaming again, along with its 15 colleagues. They'll stop when they feel like stopping. And not a second before. And (2) the app only *sometimes* shows which device thinks there’s fire. Usually you have to search for the offending device by looking for the one with a red light flashing. Ultimately these feel unsafe to us. They've trained us to assume there's no fire even when they're screaming otherwise. We've even stopped checking for fire/smoke. The smoke alarms that cried wolf... Again, the company is standing behind their product and honoring the warranty by taking all 16 alarms back. And it only took one single short phone call. I like the company, but not the product. Summary: Eleven false alarms in six months triggered by five different devices and a useless app. I strongly advise against buying this product. ... show more
Reviewed in the United States on August 20, 2026 by Kenneth F. Kroner
Trauma in a box
Style: Hardwired
I purchased the SC5 in October 2025 as a replacement for our basic smoke detectors after a small fire we had in the house. We were hoping to purchase the Nest Protect, but it had been discontinued earlier that year. The SC5 was touted as the logical replacement for the Nest Protect. I want to be clear that the SC5 is nothing like the Nest Protect. Not in looks, functionality, or reliability. Installation is very easy if you know how to use a screwdriver and wire nuts. The app is easy to install and setup as well, although Google Home has fought me with the linking of the devices. The product worked as advertised for about 4 months and then we started getting false alerts at very early hours of the morning. The alert does what it’s intended to do , it raises the dead from a deep sleep. The app does send a notification that identifies the offending device, however it doesn’t mute the device. I have had better luck with pressing the button on the device to silence the alarm, but this method is not fool proof. Ultimately the device decides when the terror is over. After the second false alarm which happened about 40 minutes later, I dove into the finer print of the device. The manufacturer recommends cleaning the device sensor every 30 days. I have never done this with any smoke detector I have owned in the past. But given the rough awakening we had recently experienced I chose to add this to my monthly maintenance list. I have 8 of these, so this is not a quick chore. It requires a can of compressed air, a microfiber cloth, and a ladder. However, even with the maintenance, we routinely experience a false alarm every 45 days almost always between the hours of 1am-4am. My family is traumatized. My daughters have recently confided in me that this is now a common fear before they go to bed that they will be awakened by the false alarm. So I will be removing these devices today with something that I hope is more reliable and hope my family can begin to sleep better knowing that we no longer have this horrible device traumatizing our lives. I highly recommend that you look for something other than this device. It has done more damage than good in the 10 months we have had them in the house. ... show more
Reviewed in the United States on September 7, 2026 by BH
Works Great with Protects
Style: Hardwired
I have a house full of Nest Protects (8 in total), the first half of which started to age out, as they only last 10 years. Since the Protect was discontinued, I had to look elsewhere. Deciding on a replacement was difficult, as frankly, every available option has its detractors/horror stories in the reviews. Ultimately, however, I threw caution to the wind and ordered 4x of the hardwired SC5s. Thankfully, the changeover proved easy: the Protects had been finicky in certain parts of the house - especially early on before presumably firmware updates fixed things - whereas the SC5 app worked flawlessly and integrated the units into my Google Home network with the remaining Protects without issue. By the time I got to the fourth unit, I was able to do the installation in about 2 minutes. About the only drawback with the SC5 is the lack of a nightlight when motion is detected; the Protects I replaced were all bedroom units, so that's not a big loss, but I'm not looking forward to replacing the hallway units in a few years, as the illumination there was a nice touch. Still, all in all, I'm covered nicely for another 10 years! ... show more
Reviewed in the United States on February 28, 2026 by T. Doyle
Bad design decisions and faulty sensors
Style: Hardwired
I replaced a house full of Nest Protect detectors with these and it has been one of the worst home technology purchases I've ever made. The only positive is that they fit the existing Nest mounting hardware. Everything else has been a downgrade. After just four months, we started getting false alarms. Not occasional chirps or low-battery warnings. Full-volume, house-wide, middle-of-the-night fire alarms. Our Nest Protect detectors ran for nearly ten years without a single false alarm. These couldn't make it half a year. What makes the experience truly unacceptable is First Alert's handling of false alarms. If the detector decides smoke levels are "too high," it refuses to let you silence the alarm. It does not matter that you're standing directly underneath it. It does not matter that there is no smoke, no fire, and no emergency. The app won't stop it. The device button won't stop it. The system simply keeps screaming. The only solution is to locate the offending detector, find a ladder, remove it from the ceiling, disconnect AC power, open the battery compartment, release the locking battery connector, and physically disconnect the battery. Then you wait for the rest of the interconnected alarms to realize there isn't actually a fire. Ask yourself whether you want to be doing that at 1:00 in the morning while your entire house is being blasted by alarms and your children are freaking out. A smoke detector has one job: reliably alert you when there is danger. False alarms are bad enough. A system that repeatedly generates false alarms and then prevents homeowners from silencing them is far worse. I wanted these to be a worthy replacement for Nest Protect. Based on my experience, they are not even close. I would not buy them again, and I would strongly discourage anyone replacing Nest Protect detectors from assuming these are a comparable alternative. ... show more
Reviewed in the United States on June 14, 2026 by Texas Y'all
Easy install, works well, but 120VAC green LED can't be turned off - a bedroom nuisance.
Style: Hardwired
Replaced 5 Nest wired smoke and CO alarms with this. Reviews were terrible but took the chance since this was the easiest path. I figured if it would be a bad experience for me, I'd return them. So far, it's been pretty easy. I setup all 5 of these alarms on my kitchen counter. Downloaded the App, scanned the QR code on each unit, named it for its intended installation location, and connected it to my WiFi. Easy peezy. The old Nest bracket would have fit this alarm but I replaced it anyway. Plastic gets brittle over time and 10 years is a lot of time. The adapter to connect between the Nest connector and the unit made it very easy. I didn't have to turn off the AC power to do this. The ceiling bracket allows you to rotate the new alarm to any position. When you connect the alarm to 120VAC, it turns on a green LED that stays on. The advantage is that you know it's not running on the backup battery. The bad is my reason for 4 stars and not 5. This feature is a creates a p-i-t-a. While there is no night light, as with the Nest, this is your de-facto night light whether your like it or not. It can't be turned off in the App. So if this alarm is in a bedroom, anyplace near a bed, you will have this LED in your eyes or illuminating the room elsewhere. I now have to find some opaque white tape to cover it. As for how smart this system is, it just gets a passing grade. The alarms don't announce the room where the issue is, only a blinking red light in that room (which you wouldn't want to, or may be need to, go into to look at it if that room was full of smoke or CO). The App would show you which room though wherever you are, and you can silence it remotely (which are still major). Overall, it is a keeper for now. Time will tell for sure. I am really not displeased. It the least hassle, closest replacement to the Nest. I don't need to think about it anymore. For this I like it just fine. ... show more
Reviewed in the United States on August 13, 2026 by Forge Ahead
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