Google Nest smoke alarm

kev2009

Hi,

I am considering a google nest smoke alarm, mains powered.  I was wondering what happens if the power goes out and then it comes back on, does the unit just come back online as normal, does it need to be re-setup? Will it just do a self check and then be ok?
My existing one is mains powered by has a battery backup so not experienced any issue, except for when it started to chirp a little while ago and i had no clue what it was until i manged to narrow do where it was coming from.  So was hoping to go pure mains and not get chirping from battery in future
Thanks

Neil_Jones

Google Nest smoke alarm, best part of £90 at Amazon at time of writing.

"normal" battery powered smoke alarm, two for £10, or a single mains powered one for £15.

Bit of a no brainer really, existing technology against something Google have knocked up?

Your existing mains powered smoke alarm is designed in such as way as to work whether it has mains or a battery.  If the power goes out, the battery takes over, and when it returns the battery recharges.  If your alarm is bleeping that normally means the battery isn't holding its charge and so needs replacing, which is the same reason why the battery operated ones chirp when they need new batteries.

The Nest unit for this has batteries so they still work in the same way as a normal smoke alarm so you can't go "totally" battery free, otherwise you'd have no protection if the power goes out.  A selling point of these is the ability to daisychain them but you can do that with existing mains ones anyway, and another selling point is to tell you what's wrong with it.  Well on the "normal" ones either it works or it doesn't, that's why you test it regularly...

kev2009

Thanks, I was looking at the Nest one as it does the smoke and Carbon Monoxide so thought might be handy plus it links up to my phone I believe so can tell if it goes off whilst not at home etc.  I'm pretty sure when I changed the battery, the existing smoke alarm that was fitted when place was built is end of life so has lasted less than 10 years (not sure how long it should of lasted but maybe builders had a load they bought and just fitted it and it was few years old) this year so I was considering a replacement and saw the nest and though doesn't look bad and it lasts for 10 years.  I'm usually not a massive fan of google products tbh but this item doesn't look too bad and gets good reviews. My long term plan is to get a Hive thermostat probably when my boiler needs replacing, which hopefully I'm looking at a good few years before that happens and so looked to see if Hive did a smoke alarm etc but didn't see one.  Also from what I can tell, I think the holes from my existing smoke alarm will line up with the nest so that's a bonus
Kev

Semple

As a nest protect owner, I can confirm these are great products. One major feature clueless Neil hadn't put down in his post is the protect's ability to notify you of a fire or carbon monoxide leak when you're not at home. Something I think most people would agree with as being a very useful feature over traditional smoke alarms.

I like the motion sensor nightlight too, which is handy if you need to get up to use the toilet in the middle of the night - you're not blinded by the landing light then. 

Self-test is another great feature, most people don't check their smoke alarms regularly enough, so this is a no brainer. 

You can get them quite a bit cheaper than £90, look out over the next month or so as that's usually when deals pop up. 

kev2009

thanks @Semple Will keep an eye out.
For the self test, can you make it quiet as opposed to hearing it all the time and then it just sends you a message if any issues as opposed to hearing it beeping or saying testing etc?
Does the mains version also have a battery inside so if power goes out its still ok?  Reason i ask is my power has a tendency to go out for a few seconds randomly usually ever few months, no idea why and its literally out for few seconds and back.  Nothing trips out, it seems more like power to property goes out and comes back.
Thanks
Kev

kev2009

Also, any suggested suppliers as I've seen online some people have ordered them and got one which is already a few months old, which i presume is due to company ordering in bulk and then they haven't sold them that quickly.  Just want to avoid getting one say 2 years old or something
Thanks
Kev

Sandtree

kev2009 said:

thanks @Semple Will keep an eye out.
For the self test, can you make it quiet as opposed to hearing it all the time and then it just sends you a message if any issues as opposed to hearing it beeping or saying testing etc?
Does the mains version also have a battery inside so if power goes out its still ok?  Reason i ask is my power has a tendency to go out for a few seconds randomly usually ever few months, no idea why and its literally out for few seconds and back.  Nothing trips out, it seems more like power to property goes out and comes back.
Thanks
Kev

I believe the self test has two tests, one a general test of if the device is working which is silent and the second to ensure the sound is working and it happens once a month. The sound test isnt loud, you can schedule when it happens (so its not in the middle of the night) and you get a prewarning message to your phone that the test is about to happen.

The Mains version does also have batteries in it for backup if the mains go down. Obviously if your wifi goes down it revents to be a bells and lights only device until the power is back up but it will then reconnect to the internet etc. Not had a powercut since installing ours but we also have the Nest doorbell (and thermostat) and when it had a wifi issue we got notification that the doorbell had gone offline along with the video of the few seconds before it went offline - presumably in case it was someone outside trying to disable the camera.

At £90 you clearly cannot say that its great value or such but they had many features which I liked such as CO as well as fire, prewarning of smoke before the alarm goes off, notifications if out the house etc. 

We bought our home in 2018, the previous owners had bought it in 2015 and when the old detector started playing up I spotted it had a replace by 2012 date in it so at least 3 owners presumably were at risk (I imagine the replace by date is conservative but still a worry)

kev2009

I bought mine in 2015 and when i replaced battery last year I think it was, i noticed it say replace by 2020 date so hence why i'm looking at options for features it provides and ease of fitting (hoping it can use same screw holes to avoid making more and filling other ones etc.
Agreed not cheap but if it lasts the 10 years, its £9 a year so not too bad
Thanks for info!
Kev

rach_k

When we had the loft converted, we splashed out and got a mains powered Nest alarm on each floor as we had to add a couple of new alarms anyway.  Honestly, it was probably one of the best things we did! 

The night light feature is really good - just enough to see down a corridor without blinding you in the dark.  Get the most out of it by placing it carefully e.g. ours are at the corners so it illuminates all routes and lights up as you leave any bedroom.  

I like the different levels of alert - instead of the same scary alarm for everything, it tells you what it thinks is wrong and what you have to do.  I find that reassuring.

Another weird benefit I didn't expect was that you can look in the history to see when the night light has been on.  I can see how the cat prowls around the different floors of the house during the night.  If they were younger, it would be good for checking the kids aren't messing around every night too.

The monthly tests aren't intrusive although you can't turn off the audio because that's part of what it's testing - that it can hear.

If the power or internet goes out, they revert to dumb alarms using their internal battery.  If you have more than one alarm, they stay connected to each other with no wifi but obviously can't send you any notifications until they're back online.  

custardy

Interesting I read this thread yesterday (never having thought about smoke detectors beyond our fitted mains powered ones) to find out today we are required in Scotland to have interlinked smoke detectors by FEbruary!

kev2009

thanks, doesn't sound too bad then, might give them a go.
Can you set a date that the are tested on i.e. 1st of the month etc or does it default to 30 days from installation/activation?
Thanks
Kev