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First Alert SC9120BA Hardwire Combination Carbon Monoxide and Smoke Alarm

4.6 out of 5 stars 1,188 ratings

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Purchase options and add-ons

Brand First Alert
Power source Battery Powered
Product Dimensions 4.8D x 14.2W x 14.2H Centimetres
Alarm Audible
Sensor type Electrochemical, Ionization
Global Trade Identification Number 00029054001054
Material Carbon
Number of Items 1
Manufacturer First Alert
UPC 029054001054

About this item

  • 120-Volt hard-wired detector. Electrochemical, Ionization sensor type
  • Alarm is wired directly into your electrical system and includes a battery backup and mute button
  • Battery backup ensures alarms work even during power outages
  • Combination smoke and CO alarm eliminates the need for 2 electrical boxes
  • 5-year limited warranty
  • Loud 85db Siren

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From the manufacturer

first alert, smoke detector, carbon monoxide, CO detector, fire alarm

First Alert SC9120BCA Hardwire Combination Carbon Monoxide and Smoke Alarm

The First Alert BRK SC9120BCA Hardwired Combination Smoke and Carbon Monoxide Alarm detects both carbon monoxide and smoke in a single device. It is designed for hardwired installation but features a battery backup that allows the unit to function in the event of a power outage. The CO smoke detector can be connected to other compatible BRK or First Alert CO smoke detectors within a single-family residence.

What's in the Box:

  • First Alert BRK SC9120BCA Hardwired Combination Smoke and Carbon Monoxide Alarm with Battery Backup and Owner's manual
  • Universal mounting bracket and hardware
  • 9-volt battery

At a Glance:

  • Hardwired CO smoke alarm features battery backup for constant monitoring
  • Can connect to other compatible BRK or First Alert CO smoke alarms
  • Lights indicate if the alarm is for smoke or for carbon monoxide
  • Single test/silence button for simple operation
  • Side-load battery compartment for convenience
first alert, smoke detector, carbon monoxide, CO detector, fire alarm

Detects Smoke and Carbon Monoxide

Designed to meet the latest construction requirements, the First Alert BRK SC9120BCA Hardwired Combination Smoke and Carbon Monoxide Alarm detects two threats: smoke and carbon monoxide. Lights on the face of the alarm tell you what the threat is, and false alarms can be silenced with a single button.

first alert, smoke detector, carbon monoxide, CO detector, fire alarm

Connect to Other Alarms for Greater Coverage

This hardwired combination smoke and carbon monoxide detector can be connected to other compatible BRK or First Alert CO smoke detectors within a single-family residence. Once one alarm is triggered, all connected CO smoke alarms will sound. The latching alarm indicator on the CO smoke alarm automatically identifies which unit initiated the alarm--even after the conditions that set off the alarm have subsided.

Easy to Install and Maintain

The First Alert BRK SC9120BCA Hardwired Combination Smoke and Carbon Monoxide Alarm integrates with existing wiring and features a universal mounting bracket that makes installing the unit quick and easy. The side-load battery compartment makes changing the 9-volt battery simple. Tamper-resistant locking pins prevent unauthorized disabling of the CO smoke alarm.

first alert, smoke detector, carbon monoxide, CO detector, fire alarm

About First Alert

For nearly 60 years, First Alert has been an innovator in the home safety industry, helping its customers protect what matters most. From smoke detectors and carbon monoxide alarms to security cameras and safes, the company manufactures reliable, technologically advanced products that offer a sense of preparedness and peace of mind. First Alert also takes pride in community outreach and has maintained a longstanding commitment to fire service support and safety awareness.

Product description

Combination smoke and CO alarm eliminates the need for two electrical boxes and features a permanently installed CO sensor and a dual ionization smoke sensor. The quick plug-in connectors for easy installation can be interconnected with up to 12 First Alert smoke alarms and 6 additional devices. The alarm is wired directly into your homes electrical system and includes a battery backup and mute button. Hard-wired detectors with battery backup ensures alarms work even during power outages. Battery installation and removal can occur while the unit is mounted to the ceiling or wall via the side load battery compartment. The mute feature silences nuisance alarms, single button tests alarm functions and alerts when it is time to change battery. The First Alert SC9120BNCA Hardwire Combination Carbon Monoxide/Smoke Alarm comes with a 5-year limited warranty. First Alert is the most trusted brands in home safety. Our mission is helping protect the lives, well being and the valuables of our customers.

Product information

Technical Details

Manufacturer ‎First Alert
Place of Business ‎AURORA, IL, 60504 US
Part Number ‎SC9120BCA
Product Dimensions ‎14.22 x 4.83 x 14.22 cm; 310 g
Item model number ‎SC9120BCA
Is discontinued by manufacturer ‎No
Material ‎Carbon
Power Source ‎Battery Powered
Item Package Quantity ‎1
Included Components ‎smoke and carbon monoxide alarm
Batteries Included? ‎No
Batteries Required? ‎No
Warranty Description ‎5-year limited warranty
Item Weight ‎310 g

Additional Information

ASIN B005M1UMDC
Customer Reviews
4.6 out of 5 stars 1,188 ratings

4.6 out of 5 stars
鶹 Rank
Date First Available Sept. 9 2011

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First Alert SC9120BA Hardwire Combination Carbon Monoxide and Smoke Alarm


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Top Brand: First Alert

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Price-10%$56.00
List:$61.99
$49.99$72.78$39.99$24.40-20%$50.74
Was:$63.14
Delivery
Get it by Saturday, Aug 9
Get it by Tuesday, Aug 5
Get it by Tuesday, Aug 5
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Customer reviews

4.6 out of 5 stars
1,188 global ratings

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Share your thoughts with other customers

Customers say

Customers like the easy installation, performance, and quality of the gas smoke fire alarm. They mention it works well, is a replacement for an expired existing unit, and is a good smoke and CO2 detector. Customers also appreciate the fit. However, some customers disagree on the battery life, noise, and wiring.

111 customers mention "Easy installation"106 positive5 negative

Customers find the gas smoke fire alarm easy to install. They mention the pins and ceiling mount fit making installation easier. Customers also say the alarms are easy and simple to replace.

"Easy to install. Working great so far. I would recommend." Read more

"...alarm needed replacing and this unit was an exact match and easy to install." Read more

"Very easy to install. I read some earlier reviews complaining about the manufacturing date...." Read more

"...Box was poor shape but nothing was missing. Easy installation. Will buy again." Read more

109 customers mention "Performance"101 positive8 negative

Customers are satisfied with the performance of the gas smoke fire alarm. They mention it works well, is reliable, and lasts for 10 years.

"Exactly replacement for a defective one. Works great. A bit more expensive than buying a multi pack." Read more

"Perfect!" Read more

"...The used unit sold by E-MATION was made in November 2024 and works great. Box was poor shape but nothing was missing. Easy installation...." Read more

"...Turned out that it was ok. Works well, good fit for the replacement that we needed. Product came quickly." Read more

59 customers mention "Quality"53 positive6 negative

Customers like the quality of the gas smoke fire alarm. They mention it's a proven design from a long-established company.

"Great product" Read more

"Easy to install. Good product" Read more

"great product" Read more

"Good Product ! Cheap price as well!" Read more

59 customers mention "Replacement"52 positive7 negative

Customers like the replacement of the gas smoke fire alarm. They mention it's a simple, perfect, and exact replacement for what was previously installed. Some say it works as expected and is compatible with the one being replaced. However, some customers have reported that the mounting plate needs to be replaced.

"Perfect replacement" Read more

"Good replacement for combo unit" Read more

"...Monoxide and Smoke Alarm has proven to be an indispensable addition to my studio and living space, providing reliable protection against two of the..." Read more

"Exact replacement for what was previously installed." Read more

18 customers mention "Fit"18 positive0 negative

Customers like the fit of the gas smoke fire alarm. They mention it fits their 4 year old base, has a great smaller profile, and is a compact unit with both smoke and CO detection. Customers also say it's convenient.

"Replaced five year old unit with upgraded one with battery backup Perfect fit Fast delivery" Read more

"On time, good price , convenient. Thanks" Read more

"...Turned out that it was ok. Works well, good fit for the replacement that we needed. Product came quickly." Read more

"I replaced my smoke detector with this 2-in-1 and it snapped right into place. Same plug and mounting bracket...." Read more

41 customers mention "Battery life"17 positive24 negative

Customers have mixed opinions about the battery life of the gas smoke fire alarm. Some mention it comes with a battery back up, while others say the faulty batteries are replaced without having to remove the alarm from the base.

"It came with a dead battery. Not something I would expect buying a brand new product. I would like a new battery please." Read more

"...installation ensures a continuous power source, eliminating the need for battery replacements and minimizing the risk of downtime...." Read more

"The battery died in 3 days. Once replaced, works fine" Read more

"...reliable protection for your family, especially with the battery backup for power outages. It feels great to be up-to-date and protected...." Read more

30 customers mention "Noise"13 positive17 negative

Customers have mixed opinions about the noise of the gas smoke fire alarm. Some mention the alarm's loud, piercing sound ensures protection. Others say it keeps making beeping noise every few seconds and has a zillion different beeps that all mean different things.

"...I install it, push the little side are in, and it starts beeping (making the dog super antsy)...." Read more

"...carbon monoxide quickly and accurately, providing early warning alerts to potential dangers. **Easy Integration:**..." Read more

"Old one was 8 years old and started chirping. Easy enough to replace" Read more

"...As well, it starts a 5 year clock, and beeps when it kills itself. That's right, only 5 years...." Read more

12 customers mention "Wiring"8 positive4 negative

Customers have mixed opinions about the wiring of the gas smoke fire alarm. Some mention it's hard wired and interconected, while others say it's directly wired and no wiring needed.

"...Reconnected the 3 wires, took all of 5 minutes. Works as advertised!" Read more

"I ordered two of these and one of them was missing all the required wires and I was forced to return" Read more

"Just needed the main unit to replace others in the house, no wiring needed. Just plugged it in." Read more

"Compact unit with both smoke and CO detection, hard wired with battery back-up. All bases covered...." Read more

As good as original equipment
5 out of 5 stars
As good as original equipment
I needed to replace an 8 year old First Alert SC9120BCA connected to all upstairs combination CO smoke alarms. Since First Alert has discontinued this model, and no 鶹 sellers state expiry dates, I was hesitant to buy online. No problem! The used unit sold by E-MATION was made in November 2024 and works great. Box was poor shape but nothing was missing. Easy installation. Will buy again.
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Top reviews from Canada

  • Reviewed in Canada on February 17, 2024
    Verified Purchase
    As someone deeply invested in various creative endeavors and content creation, safety and peace of mind are paramount to me, both in my workspace and at home. The First Alert SC9120BCA Hardwire Combination Carbon Monoxide and Smoke Alarm has proven to be an indispensable addition to my studio and living space, providing reliable protection against two of the most common household hazards.

    **Dual Protection:**

    What sets this alarm apart is its dual functionality, combining carbon monoxide and smoke detection in one unit. This means I can trust that my workspace and home are safeguarded against both invisible carbon monoxide leaks and potential fires. Whether I'm immersed in jewelry design, 3D modeling, or streaming content for my audience, I can focus on my craft with peace of mind knowing that this alarm is standing guard.

    **Reliable Performance:**

    The First Alert brand is synonymous with reliability and quality, and this alarm lives up to that reputation. Its hardwire installation ensures a continuous power source, eliminating the need for battery replacements and minimizing the risk of downtime. The alarm's advanced sensors detect both smoke and carbon monoxide quickly and accurately, providing early warning alerts to potential dangers.

    **Easy Integration:**

    Installing the SC9120BCA alarm was a breeze, thanks to its seamless integration with my existing hardwired system. The universal mounting bracket allowed for hassle-free installation, and the simple setup process meant I was up and running in no time. Additionally, its compatibility with other First Alert alarms in my home ensures a synchronized response in the event of an emergency.

    **Sleek Design:**

    In addition to its top-notch performance, I appreciate the sleek and unobtrusive design of this alarm. Its low-profile silhouette blends seamlessly into my studio and home decor, without compromising on functionality. The LED indicator lights provide clear visual cues, while the alarm's loud, piercing sound ensures that it's impossible to miss in the event of an emergency.

    **Final Verdict:**

    Overall, the First Alert SC9120BCA Hardwire Combination Carbon Monoxide and Smoke Alarm offers unmatched peace of mind and protection for both my creative workspace and living environment. Its dual functionality, reliable performance, easy integration, and sleek design make it a must-have for any artist, creator, or homeowner prioritizing safety. I highly recommend this alarm to anyone looking for a reliable and comprehensive solution to household safety.
    3 people found this helpful
    Report
  • Reviewed in Canada on July 6, 2025
    Verified Purchase
    Easy to use and to fix, works well, good product
    Customer image
    5.0 out of 5 stars
    Good better best

    Reviewed in Canada on July 6, 2025
    Easy to use and to fix, works well, good product
    Images in this review
    Customer image
  • Reviewed in Canada on June 6, 2025
    Verified Purchase
    Our old smoke alarms were past their expiry date, so it was time for an upgrade. I am so glad I went with these First Alert combo units! Being a homeowner in Barrie, safety is a top priority, and getting both smoke and carbon monoxide detection in one device is fantastic. It looks so much cleaner on the ceiling than having two separate alarms.

    The installation was incredibly easy. I was replacing older First Alert models, and the wiring harness and mounting bracket were a perfect match. I had three of them swapped out in under 15 minutes. It's such a simple process for such an important piece of safety equipment.

    There's nothing better than the peace of mind knowing you have new, reliable protection for your family, especially with the battery backup for power outages. It feels great to be up-to-date and protected. Highly recommend this for any homeowner looking to upgrade!
  • Reviewed in Canada on May 19, 2024
    Verified Purchase
    Very concerned when we received the package. It was packed in bubble envelope and when we opened the bubble pack, the box was crushed all over. Enough that we took pictures prior to installing it as we were concerned that it would be broken. Turned out that it was ok. Works well, good fit for the replacement that we needed. Product came quickly.
  • Reviewed in Canada on June 16, 2025
    Verified Purchase
    I needed to replace an 8 year old First Alert SC9120BCA connected to all upstairs combination CO smoke alarms. Since First Alert has discontinued this model, and no 鶹 sellers state expiry dates, I was hesitant to buy online. No problem! The used unit sold by E-MATION was made in November 2024 and works great. Box was poor shape but nothing was missing. Easy installation. Will buy again.
    Customer image
    5.0 out of 5 stars
    As good as original equipment

    Reviewed in Canada on June 16, 2025
    I needed to replace an 8 year old First Alert SC9120BCA connected to all upstairs combination CO smoke alarms. Since First Alert has discontinued this model, and no 鶹 sellers state expiry dates, I was hesitant to buy online. No problem! The used unit sold by E-MATION was made in November 2024 and works great. Box was poor shape but nothing was missing. Easy installation. Will buy again.
    Images in this review
    Customer imageCustomer image
  • Reviewed in Canada on July 17, 2025
    Verified Purchase
    Just work as a perfect replacement for smoke alarm only of the same products.
  • Reviewed in Canada on July 24, 2025
    Verified Purchase
    Arrived when expected. Easily installed and no issues with connection to other units in house.
  • Reviewed in Canada on June 2, 2025
    Verified Purchase
    It was used by our builder, and it last for 10 years.

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