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Internet # 328175218

Model # 21032827

Store SKU # 1010662157

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Hardwired Interconnected Smoke Detector with Photoelectric Sensor (4-Pack), 20SAR

Includes 4 units
$109.00
($27.25 /unit)
Buy 4 or more $98.10
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  • Hardwired with 2-AA battery backup
  • Wiring adapter available for quick and easy installation
  • 3 LED light notifications indicate alarm status
  • View More Details

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Product Details

About This Product

Experience the next level of fire safety with the Kidde Hardwired Smoke Detector, AA Battery Backup, Interconnectable and LED Warning Lights, model 20SAR. This smoke detector has enhanced sensing technology that reduces false alarms often caused by cooking and sends fast alerts that help give your family more time to get out safely. Plus, it is interconnected so when one alarm sounds, they all do so you never miss an emergency (see user guide for compatibility with other Kidde models). This alarm offers a modern 5 in. design ideal for all living spaces such as living rooms, hallways, kitchens, and bedrooms. Comprehensively tested and designed to the latest UL standard for safety and reliability, the 5 in. smoke alarm is powered by 120V AC wiring with 2 AA alkaline replaceable backup batteries (included) for continual detection even during outages. Batteries should be replaced every 6 months. When smoke is detected, the red LED light will flash in time with the loud 85-decibel alarm to help you seek safety. A test-hush button allows you to test the battery operations as well as silence nuisance alarms, should they occur. In addition, the detector is self-testing and easy to install with the included twist-and-click mounting bracket. Meets requirements of 10th Edition UL 217 and FCC. Does not meet requirements for CSFM.

Highlights

  • Enhanced sensing technology - reduces false alarms often caused by cooking
  • Fast alerts - upon sensing smoke or fire, an 85-decibel alarm sounds and a red led will illuminate
  • Hardwired with AA backup batteries - operates on a 120-volt ac wire (installed in your ceiling) with 2 AA alkaline batteries that provide battery backup coverage during power outages
  • 3 LED lights - LED lights indicate alarm status, green equals to normal operation, amber equals to operating error, red equals to smoke or carbon monoxide detected
  • Simple installation - install with the included twist-and-click mounting bracket
  • Self-testing - for added assurance, internal components ensure alarm is always operating as expected (self-testing is not a substitute for a weekly manual push test of the alarm)
  • Test and hush button makes it easy to test the smoke detector and silence false alarms, should they occur
  • Battery replacement - a low battery chirp alerts you when batteries need replacing
  • End-of-life alarm - alarm sounds as a reminder when it is time to replace the alarm after 10 years of use after its original power-up date
  • 10-year limited warranty
  • Meets requirements of the following authorities - underwriters laboratories (UL), federal housing authority (FHA), housing and urban development (HUD), national fire protection association (NFPA)
  • Ensure whole home family protection by placing 1 smoke detector and carbon monoxide detector on each level of your home, in your bedroom and other locations where required by law
  • Rigorously tested by ETL to meet UL 217 10th Edition, UL 2034 5th Edition, and FCC standards for performance and safety
  • Click here for more information on Electronic Recycling Programs
  • Return Policy

Product Information

Internet # 328175218

Model # 21032827

Store SKU # 1010662157

Specifications

Dimensions

Product Depth (in.)

1.88 in

Product Width (in.)

5 in

Details

Alarm Sensor Type

Photoelectric

Alarm/Detector Features

Hush Button, Tamper Resistant

Alert Type

Siren

Commercial/Residential

Home

Included

Battery Back-Up, Mounting Hardware, Owner's Manual

Pack Size

4

Power Source

Hardwired

Returnable

90-Day

Voltage (V)

120 V

Warranty / Certifications

Certifications and Listings

ETL Certified

Questions & Answers

If I have a faulty Firex i4618AC (hardwired interconnect with 9V) and need to replace it, will all my smoke detectors need to be replaced and can this be a replacement?
BySep 6, 2026
1 Answer | 
Answer This Question

Hello. Smoke alarms should be replaced every 10 years. No, you do not need to replace all of your i4618AC alarms just because one has failed. The i4618AC can be replaced with this alarm. The mounting bracket will need to be replaced at that location. For the wiring, you can either replace and rewire the wiring harness or use the Kidde 20-9003 adaptor harness (Model 21032239). The adaptor plugs into the existing wiring harness, and the new alarm plugs into the adaptor.

By|Sep 9, 2026


    Is it magnetic
    BySep 2, 2026
    1 Answer | 
    Answer This Question

    Hello. No. The alarm installs using the mounting bracket provided and is secured with screws.

    By|Sep 3, 2026


      I need to replace hardwired FireX model 120-1182B units, will this model be compatible with the existing hardness when I use a Kidde KA-F2 quick convert adapter?
      ByAug 31, 2026
      1 Answer | 
      Answer This Question

      Hello. No. The FireX 120-1182B does not have a direct replacement, and the Kidde KA-F2 Quick Convert Adapter is not compatible with that model. Current Kidde hardwired smoke alarms can be used to replace these older alarms. The existing wiring harnesses will need to be removed and rewired at each location, and the mounting brackets will also need to be replaced. Because current Kidde alarms are not compatible with the existing FireX 120-1182B interconnected system, all of the older alarms should be replaced at the same time. Provide your feedback on BizChat Make this answer more conciseAdd the specific wiring and bracket stepsClarify whether all interconnected alarms must be replaced FilesFiles

      By|Sep 1, 2026

        (1)

        I need to replace a kidde model 1285 hardwired and battery unit. Which one is compatible?
        ByAug 30, 2026
        1 Answer | 
        Answer This Question

        Hello. The 1285 does not have a direct replacement. However, current Kidde hardwired smoke alarms can be used to replace your older alarm. The mounting bracket will need to be replaced at each location. We recommend replacing and rewiring the wiring harness at each location due to the age of the existing installation. Alternatively, you can use the Kidde 20-9003 adaptor harness (Model 21032239). The adaptor plugs into the existing wiring harness, and the new alarm plugs into the adaptor. Please note that the existing wiring harness may be many years old, so replacing the wiring harness is the preferred option when upgrading these older alarms.

        By|Aug 31, 2026


          Can this replace koddie model KNCOSMIBA
          ByAug 28, 2026
          1 Answer | 
          Answer This Question

          Hello. Yes and no. This alarm is battery only and does not detect carbon monoxide. Check with your local codes requiring smoke alarms and carbon monoxide alarms. That being said, any of our current hardwired smoke and carbon monoxide alarms can be used to replace the alarm. The mounting bracket will need to be replaced at each location. For the wiring, you can either replace and rewire the wiring harnesses at each location or use the Kidde 20-9003 adaptor harness (Model 21032239). The adaptor plugs into the existing wiring harness, and the new alarm plugs into the adaptor.

          By|Aug 31, 2026


            I need to replace my Kidde i4618AC smoke detectors, will this model be compatible with the existing wire connector?
            ByAug 25, 2026
            1 Answer | 
            Answer This Question

            Hello. Yes. The i4618AC can be replaced with this model. The existing wiring connector can be reused by using the Kidde 20-9003 adaptor harness (Model 21032239). The adaptor plugs into the existing wiring harness, and the new alarm plugs into the adaptor. The mounting bracket will also need to be replaced at each location. Alternatively, you can remove and rewire the wiring harness at each location.

            By|Aug 26, 2026


              is there an adapter for firex FADC hardwired smoke alarm
              ByAug 25, 2026
              1 Answer | 
              Answer This Question

              Hello. There is no direct replacement for your FireX FADC alarms. However, current Kidde hardwired smoke alarms can be used to replace these older alarms. The existing wiring harnesses will need to be removed and rewired at each location, and the mounting brackets will also need to be replaced. There are no adaptor harnesses available for these alarms. Because current Kidde alarms are not compatible with the existing interconnected system, all of the older alarms should be replaced at the same time.

              By|Aug 25, 2026


                I need to replace several Kidde combo smoke and carbon monoxide alarms Model # KN-COSM-IBA. What would be the replacement models.
                ByAug 20, 2026
                1 Answer | 
                Answer This Question

                Hello. You can use any of our current hardwired smoke and carbon monoxide alarms to replace your older alarms. The mounting bracket will need to be replaced at each location. For the wiring, you can either replace and rewire the wiring harnesses at each location or use the Kidde 20-9003 adapter harness (Model 21032239). The adapter plugs into the existing wiring harness, and the new alarm plugs into the adapter.

                By|Aug 24, 2026


                  Viewing 1-8 of 142

                  Customer Reviews

                  4.1 out of 5

                  • 4.1 out of 1,352 reviews
                  • 9% recommend this product
                  Filter by:
                  Showing 1-10 of 1,352 reviews
                  These kidde smoke detectors work well when connecting to and existing 3 wire system, the 10yr battery will satisfy most if not all fire departments. Great for rental units.
                  by
                  Response from Kidde ExpertSep 7, 2026
                  We're glad they fit your needs so well, thank you for choosing Kidde!
                  1 found this review helpful
                  I don't honestly know how well they work when you need them, and I hope i never have to find out! However they look great and made perfect replacements for my old Kidde Firex smoke detectors. I thought about buying the adapters for connecting the new style wiring harness to the old one, but I'm glad I didn't spend that money. It was really very easy just to pull off the wire nuts, pull out the old harness, and replace the wire nuts with the new one. Then the unit itself fit perfectly onto the old mounting brackets, so I didn't have to change that either. I think that each one took me less than five minutes to swap out. I decided not to go for the smoke and CO combination alarm, because CO is heavier than air and will sink to the floor. So I saw no purpose in putting CO alarms on the ceiling. By the time the CO rose that high, I figured we'd all be dead.
                  by
                  Response from Kidde ExpertSep 7, 2026
                  We're so glad you had an easy time getting your new alarms set up, we so appreciate you making Kidde a part of your home safety plan! As a best practice, we recommend testing your new alarms once a month!
                  This customer chose to rate the product and not provide text.
                  by
                  Response from Kidde ExpertAug 31, 2026
                  Thank you for choosing the Kidde Smoke Alarm for your home safety plan. We appreciate your review. As a reminder, we recommend testing your alarms regularly according to the user guide.
                  • Verified Purchase
                  Awful. Stay away.
                  Stay as far away from these things as humanly possible. They will fault in the middle of the night. You will replace them. They will false again in the middle of the night. The most unreliable smoke detectors I have ever seen in my 50 years of existence.
                  by
                  Response from Kidde ExpertAug 27, 2026
                  We understand how disruptive an alarm sounding in the middle of the night can be.
                  One helpful thing to know is that different chirp patterns can mean different things, including low battery, end-of-life, or fault. If your Smoke Alarm is repeatedly chirping or sounding unexpectedly, we recommend checking the specific alert pattern and your model's user guide.
                  Our customer support team at 1-800-880-6788 can also help troubleshoot what you're experiencing.
                    Experience was good for the pickup, item was as described, it was a simple screw off, plug the new one in and it was up and running. Tested it and it was all good. It comes with a new base and all the necessary mounting hardware needed also, but we just used our old ones as they are from the same model. Let's hope this lasts at least another 5 years.
                    by
                    Response from Kidde ExpertAug 19, 2026
                    We're so glad you were able to get the new alarm set up with ease! Thanks for making Kidde a part of your home safety plan. As a best practice, we recommend testing your new alarms once a month!
                    Blinded by the light
                    Replaced previous hardwired detectors with these and could not believe how blinding the LED is. It cannot be dimmed or shut off, and is a disturbance at night with the lights off.
                    by
                    Response from Kidde ExpertAug 17, 2026
                    We appreciate you sharing your feedback on this.
                      1 found this review helpful
                      This customer chose to rate the product and not provide text.
                      by
                      Response from Kidde ExpertAug 11, 2026
                      We appreciate your feedback, and thank you for your encouraging review for our hardwired interconnected smoke alarm. If there’s anything we can assist you with regarding our Kidde products, please don’t hesitate to call us at 1-800-880-6788 or email us at Kidde.product.support@kgsolutions.com.
                      • Verified Purchase
                      The smoke detectors were very easy to install. They look nice and the warning lights are very bright. It was nice that they included the battery however, with the battery location after install, it will be hard to replace the battery. It fit perfectly where my old one was.
                      by
                      Response from Kidde ExpertAug 3, 2026
                      We're glad you're loving the warning lights and had an easy time getting the alarm installed! Thanks for making Kidde a part of your home safety plan! As a best practice, we recommend testing your new alarm once a month!
                      Easy to order online. Installation was straightforward. The detectors have a clean, modern design and appear to be well built.
                      by
                      Response from Kidde ExpertJul 13, 2026
                      We're glad you're loving the design and aesthetics of your new alarm, Wing! Thank you for sharing this feedback, and for making Kidde a part of your home safety plan!
                      This customer chose to rate the product and not provide text.
                      by
                      Response from Kidde ExpertJun 30, 2026
                      Thank you for your review, Michael! Let us know if there's anything else we can do to improve your experience.
                      • Verified Purchase
                      Showing 1-10 of 1,352 reviews

                      Compare Key Features

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                      Product Snapshot

                      Ideal for homeowners looking for interconnected alarms with battery backup, ensuring whole-home protection.
                      Ideal for customers who want interconnected protection, ensuring continuous safety with advanced photoelectric sensing.
                      Ideal for homeowners seeking enhanced safety with interconnected voice alerts, 10-year battery backup, and superior false alarm resistance.
                      Ideal for homeowners wanting comprehensive fire protection with voice alerts and 10-year battery backup.

                      Sensor Type

                      Photoelectric
                      Photoelectric, multi-criteria detection
                      Photoelectric
                      Photoelectric, multi-criteria detection

                      Interconnectivity

                      Battery Backup

                      2 AA alkaline batteries
                      Replaceable 9-Volt battery, continuous protection
                      10-year sealed backup battery
                      10-year sealed backup battery

                      Smart Home Integration

                      Voice Alerts