Customer Reviews for First Alert SC5 Hardwire Smart Smoke and Carbon Monoxide Alarm

I used First Alert SC5 device to replace my expired nest smoke detector they no longer produce smoke detectors and this is the recommended replacement. It was super easy to swap out as it comes with an adapter cable for the power and fit the old next celling mount. The application was easy to setup and pair with the First Alert application and link the application to my google app I have a mixture of old and new devices and no issue to report with that. I will be purchasing more to replace the rest. It has meet all of my expectations except on the nest you had the option to detect someone at night and it put out a dim night light I miss that feature. The home depot ordering and deliver was very simple and product arrived when expected.

Easy install and setup. Came with adapters and wiring harness. Was able to interconnect it with another wired alarm. App was easy to use. The only reasons not 5 stars is that 1 of the alarms has been dropping and rejoining WIFI with strong signal. Also was confusing in install instructions about having to get Google Nest and Google Home app which are not needed.

Ours gives false alarms. No smoke, no dust, no nothing. Very expensive device to do that and disappointed.

Easy to install - replaced nest protect that had expired - easy setup on app- lacks light that nest protect had

I needed to replace all 4 of my Nest smoke/CO2 detectors as they had all come up on their 10 year anniversary. I wanted a new product that would install easily using the same base plate. This product was perfect. We have 10 feet ceilings which can be challenging, the wires included in the box adapt to the wires from our old Nest units and it took less than a minute to get each installed.

We have tall ceilings and it would be difficult to turn off our smoke alarms without going to the garage with a ladder. With a smart smoke detector and the other detectors being hard wired, I am hoping I could turn off false alarms through the app. The one thing that is concerning for me is that the smoke detector occasionally would randomly disconnect from the WiFi. I'm hoping its a signal issue and not a hardware issue.

The installation was quick and easy. The conversion pieces to swap for the Nest Protect made things even faster. Connectivity within the app has been a bit spotty, but overall it seems okay so far. I definitely miss the pathlight feature from the legacy Nest product that this is intended to replace.

This was a replacement for my Nest Protect that aged out. Pros: Easy to install and swap out with the Nest Protect wiring in place. Easy to setup with the First Alert app. Works with Google Home and links with my current Nest thermostats. Cons: This does not have the motion sensor nightlight that the Nest Protect had. The little green light on the alarm is bright and can be annoying at night Overall this is a good smoke/CO detector that is from a reputable brand and links very well with my Google Home products.

Would not purchase. We have now had our fourth false alarm, this time at 4:00 a.m., terrifying my family. When one detector alarms, all of the interconnected detectors sound, making the situation even worse. My biggest concern is how difficult the alarm is to silence. The instructions state that if the detector believes the smoke level is too high, the alarm cannot be muted. During a false alarm, that becomes an incredibly frustrating and, in my opinion, poorly designed feature. We were left with extremely loud alarms sounding throughout the house while trying to figure out how to stop them. I contacted First Alert customer service and had one of the most unprofessional and bizarre customer-service experiences I have ever encountered. They ultimately agreed to replace the detectors, but after four false alarms and this experience, I have completely lost confidence in the product. I am returning the entire system. I would not purchase these again.

This crap is not worth it is a horrible product they alert with no reason

I purchased these smoke and carbon monoxide alarms to replace my previously existing and expired (after 10 years) Nest detectors. Now Google Nest no longer makes these detectors but suggests these detectors as the replacements as they are compatible with Google Home ecosystem. The First Alert detectors lack the night light feature Nest Protects had, the quality speaker and voice characteristics, and overall build quality of the units they replace. With 10 years to improve a product, sad to say they did not.

This unit is a great and easy replacement for someone currently using the google Nest system. Installation was seamless due to all possible options included, and clear directions.

I bought one to replace my Nest detector. Setup was easy. This device is terrible because of false alarms. I have two other Nest detectors expiring soon and will not purchase this to replace them.

Worst experience. False alarms almost daily, usually in the middle of the night. They have been taken down and cleaned and tested weekly like suggested but still the false alarms continue. We purchased these to replace our Nest Protects, we should have listened to other reviews. Stay far away from these and don’t waste your money.

Changed all my detectors out in my house with these. Good for about two months. Now we get false alarms at least once a week. Terrible. Don’t buy. These are all going in the trash and I’m going with a different brand.

These alarms are going to cost someone their life! They continually give false alarms. First Alert sent replacements, but within weeks they did the exact same thing. My family is so used to them, they don't even respond anymore. Very dangerous! I hope First Alert recalls these before someone dies!

Coming from our previous home with Nest Protect units, these First Alert detectors are horrible. The Nest units never had false alarms, the app worked well, loved the pathway light, the button on the unit was easy to push, the voice through the speaker was clear and if an alarm went off it was easy to silence. I also don’t remember any of the units ever losing wireless signal. The SC5 is none of these things. False alarms, daily WiFi disconnects and the overall experience with the app and hardware is very poor. The crazy thing is, if you contact the manufacturer with any issue they ask if you are cleaning the unit monthly. That is apparently the requirement. That must be in fine print somewhere but it’s just not realistic for a home with many detectors. Especially if they are hard to reach. We never cleaned our Neat units. Stay away from these, huge headache and waste of money.

If i could rate the even lower, I would! I much like many others had to replace my Nest smoke/co alarms due to them expiring. These First Alert units were advertised as drop in replacements as Google no longer produced the Nest Alarms. I have about 8 of these in my home and they are ruining my mental health. They false alarm in the middle of the night for no reason at all. I have replaced units through warranty and they seem fine for months and then BAM they go off and scare the living daylights out of my wife and kids in the middle of the night. they are so bad I am removing all of them from my home. I have gone in circles with First Alert customer service and they have stopped responding to my emails. They first told me that a refund would be possible if i provided proof of purchase directly from them. I did so and they back peddled and said a refund was not possible. They offered to replace the false alarm units as they fail one by one. well, I have replaced like 6 of the 8 and they continue to false alarm one by one. They often seem fine for months and then they start to fail again. This is a flawed product and a flawed company. A life safety device should work, period full stop. No if ands or buts they should work. It is preposterous that the solution is to live in fear of the next disruption in the dead of night and then get that unit replaced only to have it fail again in a month or two. There is no fix other than the trash can. No apology from corporate, no refund, simply suck if up buttercup. I will never buy from them again, this has wasted time, finances and energy and I am beyond over it. so long, you have destroyed your customer base by refusing to make good on a failed product. This is your legacy First Alert, bravo. "And the ghost will follow you home" lost me, lost everyone i can talk to, lost a whole commercial sector because will fight tooth and nail to not use your products in my professional life. You really screwed the pooch with this one. Did I mention that these are a poor product?

I replaced my nest system due to end of life on the CO portion with the SC5 quantity 9 units, it has been a total failure first day have a false alarm I replaced unit two days later false alarm again, called tech support they’re asking me about placement. Is there a window open and I told him I’ve had a system here for 10 years with no issues at all they did not have an answer eventually had to replace the entire system with conventional combo smoke CO.

Does not work with nest really misleading

I’ve had at least three false alarms - even middle of night… no cooking, no candle, just false alarms - unacceptable. Definite downgrade from Nest. Avoid.

I purchased 9 First Alert SC5 hardwire smoke and carbon monoxide detectors from an online retailer in March 2026. I am posting this review here because Home Depot sells this product line, and after removing this system I purchased my replacement smoke and carbon monoxide alarms from Home Depot. I installed all 9 detectors as one interconnected smoke and carbon monoxide alarm system throughout my home. During installation, 1 detector was defective out of the box and had to be replaced. About 3 months later, 1 detector went into alarm 3 times within roughly 15 minutes during the middle of the night. Because the detectors were interconnected, when 1 alarm went off, all 9 alarms went off. Earlier that day I had done some painting downstairs using low-VOC latex paint, while the alarm event occurred upstairs in the master bedroom about 5 hours later. I do not personally believe the painting caused the alarm event, but I mention it as a side note because it happened earlier that same day. While trying to silence and remove the detector during the alarm event, I had trouble with the battery release mechanism. Because the alarm was blaring and I needed to shut it down, I eventually gave up on being gentle with the battery release mechanism and used more force than I otherwise would have to disconnect it. After that, the battery wire would no longer stay connected. I also had to shut off the circuit and use a flathead screwdriver to press the release notch on the AC connector while pulling the connector out. In my opinion, the AC connector design was awkward because it required using a tool to press the notch while pulling the connector out at the same time. I contacted First Alert, and they promptly replaced that detector under warranty. Under different circumstances, I might have been willing to give the system another chance. However, because these detectors were installed and used as one interconnected whole-home life safety system and I have a pet at home, I was not comfortable continuing to rely on the system after that experience. If another alarm event occurred while I was away, I would not have been comfortable leaving my pet in the house with the alarms sounding until I could get home. For that reason, I removed the system and replaced it.

Bought six of these last summer (date of manufacture June 2025) to replace whole home “non smart” set of detectors. Worked great until it didn’t. Within a year I’ve had countless false alarms and unable to silence/dismiss from the app - whole reason I bought them! Even had to call my local fire dept. once to help. They commented they’d never seen anyone use these before and given the faulty nature they wouldn’t recommend. I’m angry at myself for spending almost $800 on electronic garbage!

We have 2 units that regularly go off with false alarms. So frequently that we assume it’s always another false alarm - and that makes them worse than useless.

I worked for this company don’t purchase it it is garbage

I bought 8 alarms late last year and I have had three separate incidents of false alarms on three seperate units. The first time I was out of the house and called the fire department. There’s no point in having smoke detectors with false alarms because you automatically assume there isn’t a fire when it goes off. Shame on First Alert for selling this garbage.

Great smoke/CO replacement for Kidde, but make sure you also buy the afapters

Middle of the night false alarms are not fun. 10 years with the Googe Nest and I never had a issue. After they expired I had to switch to the First Alert SC5 (Google Nest discontinued). They have been install for about 30 days and last night around midnight one of the units started to false alarming. And it wouldn't stop...I would silence the alarm and then about 1 minute later another false alarm. Then again...I had to remove the unit. The SC5 have terrible reviews all over the web but wanted the easy replacment of the very reliable Google Nest. Also one of the best features of the Google Nest was the pathway lighting which the SC5 does not have. I will be ripping all of these out and going with something. False alarms on a smoke detector is the worst possible thing, if you cant trust them then whats the point.

This thing is broken. Customer support is a waste of time. It works as a smoke detector, but it constantly bounces online/offline/online/offline. All customer support will do is tell you to factor reset it and watch it fail again. Highly disappointed this is the only smart detector that will integrate with the (Nest Protect) system I have in place.