Wired ZWave Smoke / Carbon Monoxide Detectors

Hi, I’m hoping someone can point me in the right direction. My house already has all wired smoke detectors in every room. I’d like to replace them with ZWave smoke detectors. I figure if it’s a wired device it would most likely act as a repeater and since the wiring is already there I might as well use it.

However I’m not able to find anything. Am I missing it or is there not one?

Thanks for the help


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I just ordered the relay to connect my existing 11 smoke/co2 detectors to smartthings. Here is the discussion thread:




However mine are so old that they need to be replaced anyways. (new house, old yellowed stuff)

Would my best bet to get the wired kind and get a relay then?

Or maybe if I’m i’m just looking to get a zwave repeater I just buy a cheap plugged in device and put that somewhere and save some money?

@JoshFink in case you did not know Carbon Monoxide fills up the house from bottom to top, so make sure that the Carbon detectors are not in the ceiling like a smoke detector. I have lost many friends due to this error.

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I don’t understand what you are trying to accomplish? Almost all our devices act as repeaters…switches, plugs, zigbee, z-wave. Some do and some don’t. But I have about 80 of them now so it doesn’t matter.
If you are trying to have effective smoke/fire/CO2 protection you have two choices:

  1. Buy a bunch of z-wave smoke alarms (none are truly interconnected with wiring). And a lot of these are battery operated and will not use AC Power that exists with your current detectors.
  2. Or do what the quoted thread suggests and wire a relay into your existing interconnected detectors.
    Obviously the most cost effective way is to buy a relay and an open/closed sensor. I was going to buy a new z-wave detector for each floor of my house when I discovered this ability to use the existing detectors. Since I have 11 installed I have great coverage and now a link to smartthings.

I seriously didn’t know about this fact. Sorry for your loss. I have a zcombo just lying on the floor on the hallway right next to my bedroom door. The reason being totally different coz the entire hallway ceiling is plastered with smoke detectors and what not (the previous owner). I couldn’t find an angle to take a picture of them all. There are 5 or 6. And was deciding which ones to get rid of.

Well one thing for sure, you will know if you have a fire or a lot of smoke (hope this never happens). I personally put a Smoke Detector in each room or at the doorway to a room. The Carbon Monoxide detectors I put near my oil or gas furnace or gas fireplace (on or near the ground).

I have one in every room (monitored by ADT) but this hallway is like crazy… At nights it’s like fireflies all over the hallway ceiling…

Sounds Pretty. Although I can imagine that other than when you need the lights, it must be annoying after a while. So why not thin it out?

I certainly don’t want to downplay anyone’s losses here, but carbon monoxide is actually very slightly lighter than air, and will rise. Generally, it just mixes with air. There are many CO detectors that are rated for ceiling mounting. In fact, every smoke/CO combo detector must be ceiling mounted.

It is a myth that CO detectors must be mounted near the floor. That probably started when the first CO detectors came out, and all of them needed to be plugged into an outlet. Also, in many homes the CO-creating devices are in the basement, so it is true that CO can fill your home “from the bottom up”, but that’s why you need a CO detector on every floor.

A functioning CO detector should sound an alarm long, long before CO at any point in the air column below it reaches a deadly level.


Check with your local fire department, this common belief does not appear to be true. Ceiling mounted CO detectors should be fine. CO is still lighter than air.

There’s a myth that all carbon monoxide alarms should be installed lower on the wall because carbon monoxide is heavier than air. In fact, carbon monoxide is slightly lighter than air and diffuses evenly throughout the room.

According to the carbon monoxide guidelines of the National Fire Protection Association (NFPA 720, 2005 edition), all carbon monoxide alarms “shall be centrally located outside of each separate sleeping area in the immediate vicinity of the bedrooms,” and each alarm “shall be located on the wall, ceiling or other location as specified in the installation instructions that accompany the unit.”


Agreed, but it takes much longer to detect CO when it is on the ceiling. Have tested this, and proved it here in VA at least with the Fire Marshall. Since then they have in law here that it needs to be done this way.

There is no current state law regarding CO detector placement in VA. Perhaps a city ordinance.

In any case, the physics are the same. Since it’s lighter than air, it will diffuse in all directions evenly.


I was trying to be the most cost effective when getting new devices, nothing really more than that. I’ve just now started getting devices in the new house I purchased and when I noticed that all of the smoke detectors were wired, I thought, “Why not?”. All of the smoke detectors in the house have yellowed from the previous owners smoke as well as I bet their 15 years old and need to be replaced anyways.

Since all of the detectors I’ve found are battery powered I figured I’d ask if maybe I was missing something.

Thanks for the help


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Even if it is true that CO can be detected sooner (which I assume was because the detector was physically closer to the source of CO emissions during this test), the fact remains that a ceiling-mounted CO detector will sound the alarm a long time before the CO levels reach a deadly level. These are spectacularly sensitive sensors.


Most devices which are plugged into power act as repeaters for zwave/zigbee. Smoke detectors and other alarms are often an exception as taking the time to pass along a message for another device might cause an alarm to be delayed. So they don’t typically factor into repeater planning, anyway.

Interlinked detectors mean an alarm condition at any one detector will set off the alarm at all detectors on the circuit, sometimes called a “whole house alarm.” But they don’t necessarily communicate with any other devices, they basically form their own mini network.

Battery powered devices rarely act as repeaters because it uses up the battery too fast.

@JDRoberts well call me surprised I thought it was a state law, but I do not see it on that page. Now I have more work to do thanks to this (SMILE). Honestly, I guess I am more tempormental about this due to the losses that I have experienced. If the manufacturer states it is ok to put in the ceiling that is fine I guess.

Since I saw the difference, mind you it was several minutes, and since I am also disabled I need every second that I can get to assure myself and family are safe.

@JDRoberts do what you want. As with all things it is a choice. I know when my gas fireplace shut down one night, the CO alarm in that room did not go off at all. It was in the ceiling, I trusted it to work, of course I trusted the Gas Fireplace to work correctly as well (SMILE). Since I moved into this house, I had no direct idea of how the detector should have been installed as it came built in this way. I know that since I added the new detector and keep it at wall socket level that when the fireplace goes out, I know it within minutes, This could just be the detector that I purchased is actually doing a good job. (Of course after multiple times of the Gas Fireplace failing, I replaced that finally which solved the problem better than the CO sensor)

Once again… I guess I should not have brought it up. And really lets be honest, simple physics states that most of the time this will only occur during heating, and hot air rises. So the logic is sound, although scientifically CO is 4 percent roughly heavier than Air. Which means to me that having it lower (not on the ceiling) is better and more likely to give you those precious seconds that can make a difference in your life.

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It’s an important question, I think it’s reasonable to look into it further. I myself am quadriparetic, wheelchair dependent with limited hand function, so I am much more conservative about fire safety than a lot of people might be. Different people have different requirements, and also different priorities for what gives them peace of mind. It’s all good. Never hurts to bring these things up. :blush:

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I completely understand. I see that you have aides as well, wish I could afford that sort of help. But, I am getting along ok, and with the extra time I am trying to help the local community more than I could before. I was always doing charity work but found it hard to balance work, (which I used to enjoy but find frustrating now) and trying to help others in need in the community.

It seems that there is no catch for those of the middle class who are falling down due to health, accident, etc. Trying to fix that here where I live. And still managing to work part time. I just cannot stop, need the money for insurance and well honestly, need to feel productive.

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Josh - back to your question. When I looked almost a year ago, the First Alert zcombo was the only combo device tested and integrated by ST. There may be others now with device support developed by the community, but I went with a couple zcombo’ sand they’ve been great. Battery only where I also had the wired option. You do get battery life indicators on the UI, the test result messaging, etc.

It would be great if First Alert (or whomever) developed a native wired version, and also one that ‘listened’ on the net and could respond to other events (eg act as an alarm)

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