Awakened by Smoke Alarms!

[Gallaher]

Small gnats! The kind that can fly through your window screens.
Summer time we always sleep windows open. The river behind the house grows lots of wildlife including bugs. I vacuum, blow smoke detectors every few months. Still have random alarms. Finally had to add “decoy lights” so that gnats fly to those instead of smoke alarms.
Works!

 

[Koolau]

Small gnats! The kind that can fly through your window screens.
Summer time we always sleep windows open. The river behind the house grows lots of wildlife including bugs. I vacuum, blow smoke detectors every few months. Still have random alarms. Finally had to add “decoy lights” so that gnats fly to those instead of smoke alarms.
Works!

Our Geckos protects our smoke alarms. Fascinating to watch them zapping the no-seeums as they evade the window screens. Mating time can be interesting as they are enthusiastic in their mating calls.

 

[ERD50]

There are some alarms that can be muted for a short time, like 10 minutes, using any generic TV style remote control. I think this should be a required standard, as it would avoid people unplugging them or getting on a ladder and hurting themselves.

 

[Koolau]

There are some alarms that can be muted for a short time, like 10 minutes, using any generic TV style remote control. I think this should be a required standard, as it would avoid people unplugging them or getting on a ladder and hurting themselves.

I love it! Will be looking for that next time.

 

[Walt34]

And when the batteries go out it seems to always be 2AM.

There's a reason for that. Not a good reason, but there is one. Many people reduce the house temperature at night, and when the back-up battery is just about to expire, that slightly lower temperature is enough to send the battery voltage low enough to trip the smoke alarm's "low voltage" circuitry and set off the alarm. At least that's what I've read on why smoke alarms go off between 2 and 4 AM.

 

[Onthefarm]

Americium-241 has a half life of 432 years so I don't think that's why you have to replace alarms​

Here's a reference that supports RetMD21's assertion:

"Why Do Smoke Detectors Expire?​

UPDATE 1
Someone asked why there’s a 10-year shelf life when an ionization smoke detector’s “Americium 241” has a half-life of over 400 years. Good question.

The NFPA recommendation may have to do with the degradation of the electronic component sensors aging and/or the reliability thereof. Also, a dual-sensor smoke alarm includes a photoelectric sensor that may be degraded over time.

UPDATE 2
“It is the sensors that fail after a given amount of time, not so much the electronic circuitry or the radioactive ionization source. The sensor modules rely on an electro-chemical reaction to smoke/CO, they get saturated over time depending on exposure and just start breaking down.”"
Source: Do Smoke Detectors Expire - Yes - Shelf Life

 

[Al18]

My Kidde 10 year smoke alarm has gone off a few times in the past few weeks, even after I cleaned it with compressed air. I had to take it down today and disable it. Apparently a 10 year smoke alarm only lasts 7 years. Bought a new one for $34 and will install it today.

 

[MarieIG]

My Kidde 10 year smoke alarm has gone off a few times in the past few weeks, even after I cleaned it with compressed air. I had to take it down today and disable it. Apparently a 10 year smoke alarm only lasts 7 years. Bought a new one for $34 and will install it today.

BTD!

 

[Walt34]

I'm still looking for the kind that won't go off when I cook a pizza in the oven....

Really, I understand why people get disgusted with the false alarms for whatever reasons and disconnect the things. I've been tempted myself. One would think they could do better than they do to reduce the false alarm rate or at least make it easy to turn the things off for a while.

 

[braumeister]

I replaced all my smoke alarms last year, as they were approaching their 10 year life expectancy. In my state, two are required for every bedroom -- one inside the door and one outside.
The kind I got (don't remember the name, just bought them at Home Depot) have a button that lets you silence them for some period of time. The one closest to the kitchen gets that button used occasionally. We have high ceilings, so I keep a yardstick handy that I can use to push that button.

Strangely, one of them went off a few nights ago, but it only lasted about 10 seconds. No idea what caused it.

My mother had her house burn down when she was a little girl, so she always made me extremely aware of possible fire hazards. And I had a smoke alarm literally save my life nearly 40 years ago so that made me even more alert to the possibilities.

 

[GrayHare]

Mine invariably starts chirping at 4 am which is when battery voltage has dropped due to cooler night temperatures. That's about the least welcome clock time to sleepily climb a shaky ladder and silence the thing. I wonder if more people have been injured by that 4 am activity than by fires.

 

[MarieIG]

Mine invariably starts chirping at 4 am which is when battery voltage has dropped due to cooler night temperatures. That's about the least welcome clock time to sleepily climb a shaky ladder and silence the thing. I wonder if more people have been injured by that 4 am activity than by fires.

Probably although the injury would be of a different type. It might be worth while to move the location.

 

[Slim11]

Mine invariably starts chirping at 4 am which is when battery voltage has dropped due to cooler night temperatures. That's about the least welcome clock time to sleepily climb a shaky ladder and silence the thing. I wonder if more people have been injured by that 4 am activity than by fires.

Change the battery 2x a year if they dont have the 10 year batteries. And thats for the hardwired ones also. Yea, they do go off at the most random times.

 

[ERD50]

... One would think they could do better than they do to reduce the false alarm rate or at least make it easy to turn the things off for a while.

I mentioned this feature upstream. When it comes time to replace ours, I'm going to ask AI to find one with all the features I want - I've found it to be pretty good at selecting products that meet a list of requirements:

There are some alarms that can be muted for a short time, like 10 minutes, using any generic TV style remote control. I think this should be a required standard, as it would avoid people unplugging them or getting on a ladder and hurting themselves.

 

[badatmath]

All mine go off at once unfortunately. I finally took down one of them and left the rest. It was the most dangerous to access as the ceiling is out of my reach. I had the entire house screaming at 2 am more than once.

 

[braumeister]

I'm not sure why folks need to use a ladder to turn off an alarm. My ceilings are high (nearly 10 feet) and I find it easy to reach the mute button with an ordinary yardstick.

 

[ERD50]

Change the battery 2x a year if they don't have the 10 year batteries. ...

I prefer to actually measure them. A load test tells you the condition better than a calendar. All mine were well within spec after 2 years, but I decided 2 years is as far as I would push it. If the curve is linear, one more year would put them on the edge of failure, and I wanted to avoid the late night chirps. Two years gives plenty of margin. And that spec allows for a long period of beeping if it did detect an alarm condition. All ours are AC powered, battery is just for power-out backup anyhow.

From my notes/research:

I read that alarm low volt detect is typically 7.2~7.7V @ 20~40 mA load. I tested them with a 120 Ohm load (~40 mA @ 8.8V). The [two year old] batteries from the Smoke Alarms measured loaded from 8.4~8.7V, and the 2 from the Combo CO alarms measured 9.39/9.40 (why like new? Maybe load test is less often?).

So well above the low threshold, even after 2 years. Replaced all with a 2025 8-pack 9V alkaline from Amazon Basics. All measured 9.64V open, 9.38V @ 220R load.

3 unused 9V batteries from 2023 (2 years old at the time) measured 9.49V open, 9.28V @ 220R load.

All were/are Amazon Basics.

 

[badatmath]

I'm not sure why folks need to use a ladder to turn off an alarm. My ceilings are high (nearly 10 feet) and I find it easy to reach the mute button with an ordinary yardstick.

Apparently you are lot taller than me.

 

[Sunset]

I'm still looking for the kind that won't go off when I cook a pizza in the oven....

Really, I understand why people get disgusted with the false alarms for whatever reasons and disconnect the things. I've been tempted myself. One would think they could do better than they do to reduce the false alarm rate or at least make it easy to turn the things off for a while.

I get the kind with a button to silence them for a while and put that near the kitchen, so I can enjoy my burnt toast

 

[Slim11]

I prefer to actually measure them. A load test tells you the condition better than a calendar. All mine were well within spec after 2 years, but I decided 2 years is as far as I would push it. If the curve is linear, one more year would put them on the edge of failure, and I wanted to avoid the late night chirps. Two years gives plenty of margin. And that spec allows for a long period of beeping if it did detect an alarm condition. All ours are AC powered, battery is just for power-out backup anyhow.

From my notes/research:

I read that alarm low volt detect is typically 7.2~7.7V @ 20~40 mA load. I tested them with a 120 Ohm load (~40 mA @ 8.8V). The [two year old] batteries from the Smoke Alarms measured loaded from 8.4~8.7V, and the 2 from the Combo CO alarms measured 9.39/9.40 (why like new? Maybe load test is less often?).

So well above the low threshold, even after 2 years. Replaced all with a 2025 8-pack 9V alkaline from Amazon Basics. All measured 9.64V open, 9.38V @ 220R load.

3 unused 9V batteries from 2023 (2 years old at the time) measured 9.49V open, 9.28V @ 220R load.

All were/are Amazon Basics.

Now try cutting the power to them after a year then load test them lol. I will bet the measurements will not be the same. They drain quickly and usally beep after a power outage or cold snap especially in un heated attics. Your the electric guy, tell me why that is? My Amazon basic batteries never lasted a year. But we do get power outages throughout the year. Change them twice a year, cheap insurance. And it depends on the co detector, the good ones always take samples , the other ones just accumulate CO and never purge sonthe have a lot of false positives. The better ones like the nighthawk, will drain a 9v in a day or less on just on battery power.

 

[ERD50]

Now try cutting the power to them after a year then load test them lol. I will bet the measurements will not be the same. They drain quickly and usally beep after a power outage or cold snap especially in un heated attics. Your the electric guy, tell me why that is? My Amazon basic batteries never lasted a year. But we do get power outages throughout the year. Change them twice a year, cheap insurance. And it depends on the co detector, the good ones always take samples , the other ones just accumulate CO and never purge sonthe have a lot of false positives. The better ones like the nighthawk, will drain a 9v in a day or less on just on battery power.

We have very reliable power, maybe a single 1 hour blackout in the past 5 years, so they are truly a backup. As long as there is AC power, the battery isn't being drained by the alarm itself. The only real draw is the occasional testing that the alarm itself does to check voltage under load (every 10 minutes? something like that). That's just a short load of 20~40 mA, probably just a few milliseconds to verify voltage with a comparator.