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Model # 21010408-N

Internet # 205465829

Store SKU # 1000535877

Worry Free Hardwired 120-Volt Interconnected Combination Smoke and Carbon Monoxide Alarm with 10-Year Battery Backup

This item has been discontinued.
The Home Depot no longer carries this specific product.

$57.97 /each




Model # 21010408-N

Internet # 205465829

Store SKU # 1000535877

NEW Kidde 120 Volt Hardwired-Interconnected 10 Year Combination Smoke and Carbon Monoxide Alarm features two sensors in one unit. The alarm is suitable as a single station and/or multiple station (24 devices) alarm. This alarm contains a ten-year lithium battery backup, removing the need to replace batteries in a hardwired unit and carries a limited 10 year warranty.

  • 120 volt AC
  • Sealed 3V lithium battery backup
  • Test/hush button
  • Voice message system
  • Peak level memory
  • Interconnected

Info & Guides

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Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Alarm Sensor Type 
Alarm Type 
Carbon Monoxide,Smoke 
Alarm/Detector Features 
10-Year Battery,Battery Back-Up,Hush Feature,Interconnected,Tamper Resistant,Voice Alert 
Commercial / Residential 
Commercial / Residential 
Connector/Contact Type 
Power Source 
Voltage (volts) 
Warranty / Certifications
Certifications and Listings 
1-UL Listed 


Rated 4.0 out of 5 by 42 reviewers.
Rated 5.0 out of 5.0 by Kidde Smoke and Carbon Monoxide Alarm with Voice alert . Kidde Fire Systems is a global leader in fire and Carbon Monoxide protection, protecting people and property, from fire hazards, and they are very trust worthy in the business. They have introduced a new generation intelligent smoke and CO and heat detectors. The all new Kidde 120 Volt Hardwired-Interconnected 10 Year Combination Smoke and Carbon Monoxide Alarm features two sensors in one unit. The alarm is suitable as a single station and/or multiple station (24 devices) alarm. This alarm contains a ten-year sealed lithium battery backup, which you will never have to replace, since the Alarm expires in 10 years. In case of a problem, it will sound the alarm and also will give you a voice memo, so that we can sleep with peace of mind. April 12, 2015
Rated 1.0 out of 5.0 by Battery DOA Purchased 2 of these unit, one of the packages was beeping non-stop (still in packaging). Once I installed it, which a bit of a trail because of where the old alarm was, the unit said battery something or other. According to the packaging this battery should have a 10 year life, will it didn't even have a few minutes. The other unit so far so good but I'm wary of the unit, again too much of a pain to remove if not absolutely necessary. Notice other feedback says units batteries are also DOA. This one of the most expensive units available at HD. Battery should be protected until actually installed then activated, pull-tab or something like that. January 21, 2015
Rated 1.0 out of 5.0 by Already have returned 7 with low battery I was replacing all 3 of my smoke detectors. As soon as I installed them I got the low battery warning. So got 3 more and all of them were low battery. So I figured it was a bad batch and went to another home depot 2 hours away where I was visiting friends. 2 of those worked. Went yo install 3rd one and got low battery. Now I will have to go back again ugh. I don't want to have to rewire for a different brand but now I wish I did. July 30, 2015
Rated 1.0 out of 5.0 by Problematic I will be making my 4th trip to the store tomorrow to exchange a new Kidde combo hardwired smoke/CO2 detector. I have now purchased 5 of these. Three had low battery chirp right away, one wouldn't even turn on, and only one worked as expected (although now I'm doubtful the battery will last the stated 10 years!). My recommendation - find another brand. July 27, 2015
Rated 1.0 out of 5.0 by Failures Installed five of these. Two kept beeping no matter what we did (returned them). 1 went off for no reason, a day after installation (12 feet up in the middle of the night). Two seem to be working, but for all we know they'll go off at some random time like the first one. Other reviewers had similar troubles, but we took a chance on these because this model seems to be the only one that combines 10-year, smoke and carbon monoxide, plus hard-wired. Home Depot needs to find another brand or pressue Kidde to improve this dud. August 11, 2015
Rated 1.0 out of 5.0 by Lasted less than 2 months Sensor started low battery alarm after less than 2 months January 14, 2015
Rated 1.0 out of 5.0 by Low battery Installed and right away low battery starts beeping. Why package products that aren't ready. Now have to travel all the way back. November 2, 2014
Rated 4.0 out of 5.0 by Positioning Alarm cannot be done properly with Kidde's Instructions The alarm after a few days seems fine BUT Kidde's Instructions on mounting and aligning the alarm are not correct. I installed and wired the unit with the "A" Linen parallel to the hall as instructed. When I engaged the alarm into the mount it ends up starting to engage the "ratcheting" section at an angle then hit the stop at a 45 degree angle and not parallel. Trying to get the alarm to parallel locked the unit and may have damaged the lugs on the unit. Had to use a strap wrench to release it from the mount. I spent days trying to figure out what I had done wrong. Finally, I called Kidde and the second person that I talked to at Kidde told me THAT THIS IS A KNOWN PROBLEM. He suggested that I turn my electrical box in ceiling which is attached to a stud. NO WAY! I finally moved the screws in my electrical box and used the wider mounting slots on the mount. I then ALIGNED THE "A" LINE PERPENDICULAR TO THE HALL, NOT PARALLEL, AND FINALLY I WAS ABLE TO ALIGN THE ALARM PARALLEL TO THE HALL SO IT FINALLY LOOKS RIGHT. Kidde needs to either change the design of the mount or the lugs on the alarm. April 27, 2015
  • 2015-10-12T12:27:44.098-05:00
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