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Availability:
In Stock.
Arrives
Sep 20 – Sep 25
Style: Hardwired
Features
- 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
- Voice alerts with Heads-Up warning tells you the type and location of danger in your home
- Equipped with Precision Detection Technology to help reduce nuisance alarms and provide an early warning
- Quick Connect Plug allows for easy installation and replacements with no need to rewire
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.
Brand: First Alert
Style: Hardwired
Power Source: Corded Electric
Color: White
Product Dimensions: 5.75"D x 1.6"W x 5.75"H
Alarm: Audible
Unit Count: 1 Count
Number of Items: 1
Item Highlight: SMCO600NV-AC
Manufacturer: First Alert
Brand: First Alert
Model Number: SMCO600NV-AC
Unit Count: 1 Count
Number of Items: 1
Item Highlight: SMCO600NV-AC
Manufacturer: First Alert
UPC: 194160013717
Built-In Media: 3V Lithium Battery Pack
Item Type Name: Combination Alarm
Mfr Part Number: SMCO600NV-AC
Power Source: Corded Electric
Alarm: Audible
Product Style: Hardwired
Color: White
Item Dimensions D x W x H: 5.75"D x 1.6"W x 5.75"H
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Sep 20 – Sep 25
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Similar Products
Top Amazon Reviews
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.
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Reviewed in the United States on March 19, 2026 by S. Simon
Style: Hardwired
Works great as a replacement for discontinued Nest model. My original purchase must hace been defective because smoke alarm kept going off so I called customer service and they sent me out a new one asap and it’s working great now.
Reviewed in the United States on August 8, 2026 by Jose A
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!!!!
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Reviewed in the United States on December 19, 2025 by Colby Plante
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.
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Reviewed in the United States on June 14, 2026 by Texas Y'all
Style: Hardwired
Was surprisingly easy to set up, connect, and install as a replacement for my expired Google nest smoke detector. Was made to replace Google nest smoke detector and works with Google home app.
Reviewed in the United States on August 30, 2026 by DP
Style: Hardwired
We have held off on posting publicly for a long time, but we've reached our limit. Today is just the latest example. Our alarms went off repeatedly throughout the night, and we got almost no sleep. This has been happening for far too long. We've done everything we've been told to do. We've replaced units, cleaned them regularly with compressed air, dusted off, and even cleaned the ceilings surrounding them with a broom every 15 days. Despite all of that, they continue to trigger false alarms. These alarms are not inexpensive, and the cost to us has gone far beyond the purchase price. They have cost us sleep, time, money, stress, and even physical injury. In one incident a few months ago, I broke my arm while trying to reach to silence one of these alarms after it went off unexpectedly in the middle of the night. We can't even feel comfortable going on vacation because we've had multiple instances where the alarms have gone off while we were away, forcing us to contact friends for help. To make matters worse, there have been times when the alarms claimed they could not be silenced, and neither the physical button nor the app would stop them. Many of those times we have had guests! Embarrassing!!! At this point, we are simply exhausted and frustrated. We expected a reliable safety product. Instead, we've spent far too long dealing with false alarms, interrupted sleep, anxiety, and ongoing maintenance that has done nothing to solve the problem. Something is clearly wrong, and defective and we hope the company takes these complaints seriously, but we no longer want to be the beta testers for these things.
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Reviewed in the United States on June 3, 2026 by superinvi
Style: Hardwired
Terrible product - I purchased 4 of these (3 wired, 1 battery) for my house because I had to replace Nest Protect. The product is cheaply made and difficult to mount to its base properly. The main problem is that it is prone to false alarms in the middle of the night. My master bedroom unit did this twice. Then I replaced it. Then the basement unit did this. Then the bedroom unit replacement unit (this purchase) did it. All in the space of several months. The alarms sometimes cannot even be silenced - the app responds "too much smoke cannot silence" even though there is no sign whatsoever of any smoke. The only way to stop it is to wait. Eventually it will let you silence it. Then it usually starts up a few times after that but eventually stops. If you look at reviews for this product this seems to happen to many people who get them. It is clearly a defective product. A good idea, but poorly implemented. Even if it worked properly, it is a big step down from Nest protect. Ugly, flimsy and no night light, no self test or any other amenities Nest protect had. Also, it claims to be compatible with Google Home, but you have to connect it to Google Home through its own app (and not a great app at that) - so one more account, one more app crowding your phone, additional complexity. If I could give this zero points I would. STAY AWAY!!!!
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Reviewed in the United States on April 7, 2026 by Ethan W.
Style: Hardwired
NOTE ***********Update 8/2/2026 Received my 6 replacement SC5 smoke detectors from First Alert. They tell me the problems have been fixed. Hopeful! Carefully installed the first one to test the unit. It has been installed almost a week now, no false alarms. Keeping my fingers crossed. Will provide another update in a few weeks. NOTE ***********( Update 24 July 2026 I contacted First Alert and shared with them my experience. Since they are within their one year warranty First Alert agreed to replace them at no cost. First Alert believes they have a fix the problem. Will provide an update after receive the new units. As previously stated in other reviews this is a defective product!!! Do not buy. I bought 6 of these to replace expiring nest protects. Used the nest protects for 10 years no false alarms. I have these in a rental property. Despite cleaning these following first alert instructions they contumely false alarm. Factory resetting does not help. . I can not rent the property due to these false alarms. Furious!!!! First alert has been non responsive despite attempts to contact.
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Reviewed in the United States on July 23, 2026 by Jack S