Customer Ratings & Reviews

Excellent! My Nest Protect expired and I was able to keep the base plate intact and just twist the First Alert on the base.

Good, works with my Nest Protect. Will buy more in the future.

Easy to setup. No issues. Syncs with all my othet nest products.

If this integrates to replace my 10-year-old Nest Protect, and controllable from the Nest app, then I'm happy!

Easy to use on the app and installation was smooth

Purchased September 2025 and had an issue three months later. Alarm started to sound and received multiple text that smoke was filling the house. Was out of town and had someone physically go by to ensure there wasn’t an actual fire. Not impressed with this product.

Easy to set up and sync up with my Google Home App.

Not as good nor as integratable as nest smoke detectors.

Many false alarms, triggered by other rooms and alarms

I was forced to purchase five of because I had NEST alarms that were expiring and this was the only compatible solution with my remaining NEST alarms that still have a few years of life. Not impressed. I’m getting notifications that there are issues with its connectivity to the Google Home app. Every time I open the Home app I’m told to finish setting up the First Alert smoke alarms, but then still get an error after doing so. This is for a second home and now I’m concerned they’re not going to alert me in a fire. They have major compatibility issues with this product.

Constantly disconnects from the app. Prone to false alarms. Significant downgrade from Nest alarms.

stinks. it doesn’t work with your Nest app and doesn’t have the night light feature. a $20 regular smoke detector does the same thing

Don’t buy! False alarms. Bought six months ago. Started false alarming repeatedly.

I wanted to get a new carbon monixide/smoke detector for my house. I have an older smart one that is going on 5 years or so from another company, but the app does not work anymore, and I cannot find a battery for it anymore either, but it still tests as working. That being said, I liked the piece of mind it di ld provide me by sending an alert to my phone if I was out of the house. This does connect to Google home and nest and is connected by wifi to your network. This comes with a quicksand guide and all you have to do is follow the guide. The app seems reasonable enough, account setup easy, and the keep the book handy following with the app because you need the qr code, and it set up in about 5 minutes. The mounting is easy also, I did use wall anchors provided and mounted it to a wall, but also can be done to a ceiling. This will send an alert to the phone which has a quick connect to authorities if needed (911). What I do like about this one vs last is it does not look like a proprietary battery, the look like 6 n size batteries I can change if it gets low. As for the sound, I tested this and by golly it will get your attention, they state it us loud and it gives you at countdown. I'd estimate around 105 to 110 dB at least. I can hear this from the back of my house very easily, and it's up in the front of the house. It is almost deafening under it when going off. So far, I have no reason not to give it 5 stars. It is way more expensive than your common smoke/co detector that is battery and non wifi, but if you want piece of mind to know about your house or ones back home (pets/family) if you are gone, this presents a a good option.

It has started. The smoke alarms that came with my house are starting to need to be replaced and I had to decide on going with a simple smoke alarm or upgrade. After checking the laws for my state for smoke alarms, I decided to give the First Alert - Smoke and Carbon Monoxide Battery Powered Detector a try. I mainly decided on First Alert by reputation and recommendation by the company that services the fire extinguisher at my job. Due to getting more paranoid as I get older, I liked the thought of having an app that will alert me to a problem when I'm away from home. I'm happy that it meets state code for all detectors in my house except for the one that needs to be sealed. The detector came well packaged and was easy to set up. I decided to set it up on the wall rather than the ceiling so I can reach it with a simple step stool rather than needing a stepladder. It went outside my bedroom which is off the kitchen where there is a gas stove. The mounting went up easily and the detector slid into place with a twist and click without issue, The app is easy to download and setup. I pulled the tab where the batteries are and it started working immediately. The green light on the detector acts as a bit of a nightlight. Testing was easy but be aware, it is loud. I also like that this is a detector that is portable so I may get one for travel if there is long battery life. Another feature I like is that these can interconnect so instead of individual devices I can make my own network. One warning is that the batteries can be expensive so hopefully they are long lasting.

I'm not sure how to write a thousand letter review on a smoke detector, but here it goes... This was super simple to set up. Quick app download, synced via Bluetooth, and connected to my Google Home and my wifi. Then came the physical installation. Two screws into the drywall held the mount platform, then a quick twist and click secured the smoke detector. A peek at the app and my Google Home both said the device was working as expected, so I am content. I will change my opinion if my house burns down without my notification. It's a large unit, roughly Mac Mini size and shape, but doesn't bring a lot of attention to itself with gaudy LED lights or anything. I think I'll get a few more for some of the other rooms in my house (although this one is placed in a central location). The app is super simple to set up and yet another account to create and log into. I just really wanted the peace of mind and security knowing that this will let us know of a carbon monoxide issue as well as the smoke, and can notify me or my wife when we aren't home. Definitely worth it.

Frequently gives false alarms. Would not recommend

This by far the most functional and reliable smoke and carbon monoxide detector I've used. First Alert is a leader in this space and this device incorporates all of their advanced features. You have the option of getting this in a hard-wired version, but this one gives you freedom to place in any location. Basic setup is straightforward and once you remove the battery protector tab, it is ready to go as basic detector. It does use a lot of expensive CR123 batteries, but these should last a long time. I don't have an issue with this because I had rather of plenty of power to make sure it is working effective. There is a QR code on the box and highly recommend downloading the software. This will allow you to connect it to your WiFi and get notifications directly to your phone. This will allow you to get notified of alerts no matter where you are at. There is also an option to connect this to other units have them all activate when one detects an issue. The battery light is a little hard to see, but the mobile app will allow you to easily see the device status at any time.

First Alert by Resideo Smart SC5 Smoke and CO Alarm It was time to replace my six year old fire alarm and I decided to try First Alert by Reisdeo Smart SC5 Smoke and CO Alarm. My previouis safety devices were separate, fire alarm plus a CO2 detector. The First Alert combines both devices into one. Included in the box is the First Alert SC5 Smoke and CO Alarm, CR123 installed batteries, wall mount, screws, and the instruction manual. The setup is very simple: pull the plastic tab attached to the batteries and then download the First Alert App from the AppStore or Google Play Store. This unit is compatible with Google Nest however, you must first download the First Alert App. If you previously owned Google Nest Protect Alarms, there is no need to change mounts as the SC5 Smoke and CO alarm will fit the base. First Alert recommends that you run a safety test weekly, which can be done using either the First Alert App or Google Nest App. During the test you will hear the voice command count down for 5 seconds then you will hear 3 very loud beeps for fire while the middle of the device is blinking red. For the Carbon Monixide test you will hear 4 short beeps with halo blinking. If you have multiple SC5 devices, each one will randomly test. Highly recommend.

Like many others I have used the Nest Protect on every floor of my home for years. Until Nest/Google decide they no longer want to support it. First Alert has been in the Smoke/Co game for a while and I don't see them going away anytime soon. Hopefully the support is there. At the core the SC5 Smart Smoke and CO Detector is a combination unit so I don't I need 2 different units which in it of itself is a plus. It's loud and obnoxious as any other Smoke/CO Detector and quick to pick up smoke in my testing (have not tested CO and I hope I never have to hear that alert). But like the Nest Protect the SC5 has Wi-Fi connectivity, which lets the detector link up to the First Alert app on your phone. Primary reason that is a benefit is that if an alarm goes off, you'll get a push notification on your phone, no matter where you are. The alarm can also be tested and silenced remotely as well as the battery status which is super convenient. This dectector can even tell you what kind of threat it's detecting—smoke or carbon monoxide—and unit (if you have multiple) in your house it's happening. The SC5 is powered by 6 123A Lithium batteries, which I have been familiar with for over a decade, but I'm sure there are many that have never heard of it. These batteries will cost more than the typical AA/AAAs but First Alert projects 3-5 years of use out of a set of 6. So 2 at most 3 battery changes throughout life of this detector. Speaking of batteries, because of the connection to the app, the SC5 will alert you via a notification when the batteries need to be replaced so you don't have to listen to that dreaded middle of the night low battery chirp. My biggest gripes; with not just this unit but all smart home devices, is that the SC5 is advertised to be able to integrate into the Nest ecosystem. I was unable to get it to connect. Although it's not a huge deal. I used to have the Nest Video Doorbell, Thermostat and Protect. One by one support ended for the older products forcing you to buy their newer products. I do not like that business model and have begun to move away from that ecosystem. First Alert is not without it's own issues. I have an older First Alert Onelink Smoke/CO Detector that has been discontinued and no longer supported. It would have been nice if they roped in some support for their own legacy devices, but we are in a new age of waste and disposable everything. Nothing is meant to last and everything is made to be upgraded every year. While I will continue to look for and use smart devices for my home, I will hesitate to outfit my entire home with these SC5 (especially at $150 per detector) and use it in conjunction with standard Smoke/CO detectors, unless I can see that First Alert will support their product for it's full life. This way (at the cost of ANOTHER smart home app added to my page of smart home devices) have some piece of mind to monitor an aspect of my home while I am away from it.