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FIRST ALERT BRK SC9120FF Hardwired Smoke and Carbon Monoxide (CO) Detector with Battery Backup, 1 pack , White

4.7 4.7 out of 5 stars 25,457 ratings
Amazon's Choice highlights highly rated, well-priced products available to ship immediately.
Amazon's Choice in Smoke & Carbon Monoxide Alarms by FIRST ALERT
$39.40
1-Pack
Detector
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Purchase options and add-ons

Brand FIRST ALERT
Style Hardwired Alarm
Power Source Battery Powered,Hardwired
Color White
Product Dimensions 1.9"D x 5.6"W x 5.6"H
Item Weight 8 ounces
Alarm Audible
Sensor Type electrochemical,ionization

About this item

  • Keep your family safe with this hardwired smoke and carbon monoxide alarm; The battery backup means constant monitoring, even if there's a power failure
  • Features an electrochemical carbon monoxide sensing technology as well as an ionization sensor for smoke detection.
  • Indicator lights on the face of the unit display the presence of smoke or carbon monoxide, while an 85 decibel siren provides a clear, loud warning upon detection
  • Can connect to other compatible BRK or First Alert detectors, to ensure all alarms will sound when threat is detected
  • Simple to use, with a single test/silence button, and side load battery compartment; Tamper resistant locking brackets and universal mounting brackets make installation easy
  • Rigorously tested to meet UL standards
  • Faster turnarounds on job sites with the easy-to-install, most-trusted alarms in home safety
  • First Alert has been the most trusted brand in home safety since launching the first residential smoke alarm in 1958 (Based on a First Alert Brand Trust Survey in February 2018)
› See more product details

Customer ratings by feature

Safety Features
4.9 4.9
Easy to install
4.6 4.6
Motion detection
4.5 4.5
Battery life
4.3 4.3
See all reviews

Frequently bought together

FIRST ALERT BRK SC9120FF Hardwired Smoke and Carbon Monoxide (CO) Detector with Battery Backup, 1 pack , White
$39.40
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In Stock
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First Alert 9120BFF Smoke Detector, Hardwired Alarm with Battery Backup, White, 1-Pack
$14.12
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In Stock
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First Alert 9120B Smoke Detector, Hardwired Alarm with Battery Backup, 6-Pack
$59.99
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In Stock
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From the manufacturer

First Alert
What is carbon monoxide?

Common sources of Carbon Monoxide

Furniture

Dryer Vent

Chimney

What does the beep mean?

4 beeps and a pause

1 beep every minute

5 beeps every minute

Emergency: Carbon monoxide has been detected. Move to fresh air and call 911.

Low battery: It's time to replace the batteries in your carbon monoxide alarm.

End of life: It's time to replace your carbon monoxide alarm.

Recommended alarm placement

Product guides and documents

Installation Manual (PDF)
Instructions for Use (IFU) (PDF)
User Manual (PDF)

Product information

Technical Details

Additional Information

Warranty & Support

Amazon.com Return Policy:Amazon.com Voluntary 30-Day Return Guarantee: You can return many items you have purchased within 30 days following delivery of the item to you. Our Voluntary 30-Day Return Guarantee does not affect your legal right of withdrawal in any way. You can find out more about the exceptions and conditions here.
Product Warranty: For warranty information about this product, please Click here [PDF ]

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FIRST ALERT BRK SC9120FF Hardwired Smoke and Carbon Monoxide (CO) Detector with Battery Backup, 1 pack , White

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Product Description

The BRK SC9120B hardwire combination smoke and carbon monoxide alarm detects two hazards with one simple unit. Carbon monoxide (CO) is a colorless, odorless, deadly gas. It can be emitted by sources including gas or oil furnaces, gas clothes dryers, water heaters, fireplaces, wood stoves, charcoal grills, gas ranges, and space heaters. A clogged chimney, improper venting, and attached garages can also cause carbon monoxide accumulation. The BRK SC9120 hardwire combination smoke and CO alarm with battery backup includes these features: Quick plug in power connector for easy installation, 120 volt AC inter connectable (with maximum 18 compatible devices 12 other compatible smoke alarms + 6 compatible devices like bells, horns, repeaters and door closers. If one unit triggers an alarm, all smoke alarms in the series will sound. Single test/silence button which both silences a non-threatening alarm or low battery warning and allows you to test the unit's functionality. Automatically performs internal test of functionality. Latching alarm indicator which automatically identifies which unit initiated the alarm. Battery drawer lock and mounting bracket lock for tamper resistance. AC power indicator and alarm indicator light. Low battery warning "chirp" and missing battery tab. 9 volt battery backup for peace of mind during power outages. All BRK Electronics carbon monoxide alarms are listed to UL Safety Standard 2034 for residential carbon monoxide alarms. Includes 9 volt backup battery. 10 year limited warranty. Includes: One combination smoke and CO alarm, one 9 volt battery, and user’s manual.Hardwired combination CO smoke alarm features battery backup for constant monitoring.

Top Brand: FIRST ALERT

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FIRST ALERT BRK SC9120FF Hardwired Smoke and Carbon Monoxide (CO) Detector with Battery Backup, 1 pack , White
FIRST ALERT BRK SC9120FF Hardwired Smoke and Carbon Monoxide (CO) Detector with Battery Backup, 1 pack , White
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Price$39.40$64.99$36.64$42.99$449.94-9% $50.03
List: $54.99
Delivery
Get it as soon as Friday, May 3
Get it as soon as Friday, May 3
Get it as soon as Friday, May 3
Get it as soon as Friday, May 3
Get it as soon as Friday, May 3
Get it as soon as Friday, May 3
Customer Ratings
4.74.7 out of 5 stars25,457
4.64.6 out of 5 stars30
4.64.6 out of 5 stars1,292
4.44.4 out of 5 stars1,068
4.64.6 out of 5 stars1,996
4.54.5 out of 5 stars1,032
Easy to install
4.6
—
4.5
4.4
4.5
3.8
Battery life
4.3
—
4.4
4.4
3.8
3.9
Value for money
4.0
—
4.2
4.0
3.6
3.8
Sold By
Amazon.com
Amazon.com
Amazon.com
X-Sense US
Amazon.com
RES, LLC
power source
Battery Powered,Hardwired
Corded Electric
Battery Powered
AC
Battery Powered
Hardwired
sensor type
electrochemical,ionization
Ionization
Photoelectric, Electrochemical
Photoelectric, Electrochemical
Photoelectric, Electrochemical
Photoelectric, Electrochemical
lower temperature rate
—
—
40 degrees fahrenheit
—
40 degrees fahrenheit
40 degrees fahrenheit
upper temperature rate
—
—
100 degrees fahrenheit
—
100 degrees fahrenheit
100 degrees fahrenheit
style
Hardwired Alarm
Smoke, CO
AC Hardwired Model XP06
Hardwired Interconnected Model (with Voice Location)
Decibel
Updated Model
alarm
Audible
Smoke, CO
≥ 85 dB
—
Audible
Fire, Smoke, Carbon Monoxide
weight
0.5 pounds
0.56 pounds
—
—
0.8 pounds
0.45 pounds

Customer reviews

4.7 out of 5 stars
4.7 out of 5
25,457 global ratings

Customers say

Customers like the quality, value, fit and ease of replacement of the gas smoke fire alarm. For example, they mention it's a reliable brand, fits right into existing housing and that it'll save money. They appreciate the performance, and ease installation. That said, some complain about the noise.

AI-generated from the text of customer reviews

1,025 customers mention986 positive39 negative

Customers find the installation of the gas smoke fire alarm to be easy. They mention that it's simple to plug in existing wiring to get smoke/carbon detection, and that it goes up easily.

"Install was super easy. Tested fine. And looks nice. I took the picture in low light to show the green light. Reliable brand...." Read more

"...Overall, they work well and are easy to install." Read more

"...Installation was super easy for a non-handy person such as myself. Thank goodness I didn’t need the hardwire adapters...." Read more

"Easy set up and now I can sleep at ease." Read more

724 customers mention619 positive105 negative

Customers like the performance of the gas smoke fire alarm. They mention that it works well, and has been trouble free so far. Some say that the test functions work clearly and loudly.

"Install was super easy. Tested fine. And looks nice. I took the picture in low light to show the green light. Reliable brand...." Read more

"...Overall, they work well and are easy to install." Read more

"...The installation was a breeze and has been trouble free so far." Read more

"Functioned well for 7.5 years. Then it starting chirping as if it needed a new battery. No battery resolved the problem and had to be replaced...." Read more

721 customers mention519 positive202 negative

Customers like the quality of the gas smoke fire alarm. They say it's a reliable brand, well-made, and a must for every home. Some say that the alarms were manufactured fairly recently and have no false alarms during their first month.

"...I took the picture in low light to show the green light. Reliable brand. I'll be buying another one too replace my other old smoke detector." Read more

"These are basic smoke alarms. From experience they last about 7 yrs. Easy to install." Read more

"This Smoke and Carbon Monoxide Detector is sensitive, but it work." Read more

"...As mentioned, these are smaller in size and detect carbon monoxide...." Read more

351 customers mention317 positive34 negative

Customers are satisfied with the value of the gas smoke fire alarm. They mention that it is a good product at a reasonable price. Some say that it saves money and is able to last for another 8 years.

"Great price. Easy to install. Used to replace older units" Read more

"...detectors are so expensive but these turned out to be the most cost effective option, they were super easy to install, AND they came with a duracell..." Read more

"...The only good thing is that they are easy to replace, and much cheaper on Amazon than the local brick and mortar stores...." Read more

"Easy to install. Good value." Read more

219 customers mention205 positive14 negative

Customers find the replacement of the gas smoke fire alarm to be easy. They mention that it takes just a few minutes, and that they don't have to rewire. Some say that the old one went bad, and it was a super-quick swap out.

"...Perfect form/fit/function fit. No need to change baseplate. Took me longer to go find the step stool than it did to do the actual part change." Read more

"...This was the exact replacement from the original. Easy swap out. I hope it can last another 8 years." Read more

"...These new units have been a very easy replacement since they use the same mounting ring and wiring harness as my original units...." Read more

"...It did! So when the old one went bad, it was a super-quick swap out. And now we have CO2 protection too...." Read more

143 customers mention134 positive9 negative

Customers are satisfied with the fit of the gas smoke fire alarm. They mention that it fits right into their existing housing, without the need for the included wires or new wall plate. Some say that the mountings fit perfectly and did not require any touch-up. Overall, most are happy with the small profile and ease of installation.

"...Each detector came with a hardwire adapter, 9V battery, and mounting brackets. Installation was super easy for a non-handy person such as myself...." Read more

"...Perfect form/fit/function fit. No need to change baseplate. Took me longer to go find the step stool than it did to do the actual part change." Read more

"...As mentioned, these are smaller in size and detect carbon monoxide...." Read more

"...These devices fit perfectly in the existing wiring harness." Read more

245 customers mention113 positive132 negative

Customers are mixed about the battery life of the gas smoke fire alarm. Some mention that it comes with a 9-volt battery included and a backup battery. However, others say that the battery is difficult to replace and almost impossible to change out without breaking the device.

"...Then it starting chirping as if it needed a new battery. No battery resolved the problem and had to be replaced...." Read more

"...Each detector came with a hardwire adapter, 9V battery, and mounting brackets. Installation was super easy for a non-handy person such as myself...." Read more

"...Lifetime has been a little shorter than I would have expected. But, the replacement process has been quick and easy." Read more

"...Also, these units come with a back up battery and the old ones did not." Read more

185 customers mention42 positive143 negative

Customers are dissatisfied with the noise produced by the gas smoke fire alarm. They mention that it makes sleeping in the bedroom impossible, and the beeping is just loud enough that you can't sleep through it. Some customers also say that the alarm starts chirping late at night, making it impossible to sleep. They also say the alarm makes a full alarm sound rather than make the little chirps.

"...When the detectors go bad, they will begin to beep and will not stop even if you replace the battery...." Read more

"...I couldn't trace the source by myself and the chirp made sleeping in the bedroom impossible...." Read more

"Functioned well for 7.5 years. Then it starting chirping as if it needed a new battery. No battery resolved the problem and had to be replaced...." Read more

"...the batteries to the contacts and got through testing each unit, all grew silent and has remained so. I hope they work well for years." Read more

It’s a lifesaver - literally (see what I did there)
5 Stars
It’s a lifesaver - literally (see what I did there)
We built our house 10 years ago and these smoke detectors are wired all through the house. Looks like the life span is 9 plus years as I have begun replacing them one at a time. In all honesty I’ve only replaced 2 out of 15 so definitely not a quality issue. I am very satisfied and could upgrade, but decided to continue with the brand since I have never had any issues. When the detectors go bad, they will begin to beep and will not stop even if you replace the battery. That is a nice feature (annoying, but understandably so). Just unplug the unit to get it to stop until the new replacement arrives. Unplugging does not seem ideal, but the unit does not work so leaving it plugged in while it beeps every 2 mins doesn’t protect you if there is a fire. Your other smoke detectors in the home will cover while you wait on the replacement. In summary, I definitely recommend this product!
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Top reviews from the United States

Ladybug
5.0 out of 5 stars Great choice
Reviewed in the United States on March 4, 2024
Size: 1-PackPattern Name: DetectorVerified Purchase
Install was super easy. Tested fine. And looks nice. I took the picture in low light to show the green light. Reliable brand. I'll be buying another one too replace my other old smoke detector.
Customer image
Ladybug
5.0 out of 5 stars Great choice
Reviewed in the United States on March 4, 2024
Install was super easy. Tested fine. And looks nice. I took the picture in low light to show the green light. Reliable brand. I'll be buying another one too replace my other old smoke detector.
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Customer image
Customer image
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Nathan
5.0 out of 5 stars Works well
Reviewed in the United States on April 18, 2024
Size: 1-PackPattern Name: DetectorVerified Purchase
This is the second set I’ve purchased. The first one lasted about eight years before one began signaling it was no longer good. I decided just to replace all of them to avoid any late night interruptions from the other detectors. Overall, they work well and are easy to install.
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VA Doc
5.0 out of 5 stars Super Easy Installation
Reviewed in the United States on April 4, 2024
Size: 3-PackPattern Name: DetectorVerified Purchase
This review is for the First Alert BRK Hardwired Smoke and Carbon Monoxide Detector with Battery Backup, 3-pack. I bought this item to replace and upgrade the smoke detectors in my home. I wanted to have a CO detector on each floor. Each detector came with a hardwire adapter, 9V battery, and mounting brackets. Installation was super easy for a non-handy person such as myself. Thank goodness I didn’t need the hardwire adapters. I did need to replace one of the mounting brackets. There are a lot of how to videos online to guide you. Remember to turn the power off at the fuse box. Overall installation time was 30 minutes.
Customer image
VA Doc
5.0 out of 5 stars Super Easy Installation
Reviewed in the United States on April 4, 2024
This review is for the First Alert BRK Hardwired Smoke and Carbon Monoxide Detector with Battery Backup, 3-pack. I bought this item to replace and upgrade the smoke detectors in my home. I wanted to have a CO detector on each floor. Each detector came with a hardwire adapter, 9V battery, and mounting brackets. Installation was super easy for a non-handy person such as myself. Thank goodness I didn’t need the hardwire adapters. I did need to replace one of the mounting brackets. There are a lot of how to videos online to guide you. Remember to turn the power off at the fuse box. Overall installation time was 30 minutes.
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Customer image
Customer image
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MELLIE
5.0 out of 5 stars Great device!
Reviewed in the United States on April 20, 2024
Size: 1-PackPattern Name: DetectorVerified Purchase
Easy set up and now I can sleep at ease.
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JLS
4.0 out of 5 stars Basic, cost effective
Reviewed in the United States on November 18, 2023
Size: 3-PackPattern Name: DetectorVerified Purchase
These are basic smoke alarms. From experience they last about 7 yrs. Easy to install.
3 people found this helpful
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Mark F.
5.0 out of 5 stars Easy replacement for very old wired smoke detector
Reviewed in the United States on April 9, 2024
Size: 1-PackPattern Name: DetectorVerified Purchase
Direct replacement for my three wire hard wired ac detector. The Carbon Monoxide was required. I was tempted to get one of the models with the display, but opted for the First Alert name. The installation was a breeze and has been trouble free so far.
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JG
5.0 out of 5 stars Upgraded my current smoke alarm only to this smoke alarm + carbon monoxide. Perfect fit.
Reviewed in the United States on March 19, 2024
Size: 1-PackPattern Name: DetectorVerified Purchase
Wanted to add carbon monoxide monitoring to my space. Already had this brand of smoke detector in the room.
Bought this and then I just unscrewed the old one from the base plate and disconnected the power cable to remove it, then attached the power cable to this new one and screwed it onto the existing base plate. Perfect form/fit/function fit. No need to change baseplate. Took me longer to go find the step stool than it did to do the actual part change.
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Honeybee
5.0 out of 5 stars I like it
Reviewed in the United States on March 14, 2024
Size: 1-PackPattern Name: DetectorVerified Purchase
This Smoke and Carbon Monoxide Detector is sensitive, but it work.
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Honeybee
5.0 out of 5 stars I like it
Reviewed in the United States on March 14, 2024
This Smoke and Carbon Monoxide Detector is sensitive, but it work.
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Top reviews from other countries

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jill
5.0 out of 5 stars works very well
Reviewed in Canada on September 14, 2023
Size: 1-PackPattern Name: DetectorVerified Purchase
this is a replacement hard wired smoke detector. I found it quite expensive.
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Michèle
5.0 out of 5 stars Carbon monoxide and fire alarm
Reviewed in Canada on September 3, 2023
Size: 1-PackPattern Name: DetectorVerified Purchase
Exactly match the one I needed to replace / same brand even if the model number had change/
Easy to install and battery included . No longer available in store. Very satisfied/
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Clyde Cohen
5.0 out of 5 stars replacement product
Reviewed in Canada on August 8, 2023
Size: 1-PackPattern Name: DetectorVerified Purchase
bought this to replace my previous First Alert Fire/Smoke alarm and it fit perfectly and does the job as intended
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bilodeau suzanne
5.0 out of 5 stars Facile d’installation
Reviewed in Canada on December 15, 2023
Size: 1-PackPattern Name: DetectorVerified Purchase
C’est le même modèle qu’on avait avant
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Spud
4.0 out of 5 stars Best for the buck?
Reviewed in Canada on October 7, 2022
Size: 1-PackPattern Name: DetectorVerified Purchase
Smoke detector is a great choice for the price, it detects smoke and carbon monoxide. Very little maintenance required. Hardwired with a battery backup. Very happy with this product.
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