It’s a common question. “Do smoke detectors expire?” Yes, over time they lose sensitivity. The last thing you want is a weak smoke detector in your room while sleeping soundly at night.
Here’s what you need to know…
The smoke detector works in the background, mounted on ceilings or walls while it constantly and continuously measures the air around it – just waiting to alarm (hopefully never!).
It works hours, days, weeks, months, years – never ending.
HOWEVER, eventually at least until one of two things will happen…
1. The batteries go dead.
2. It degrades – expires – due to its effective shelf life.
Tip: A good habit: Replace smoke detector batteries during a notable time of the year such as the New Year, January 1.
Otherwise, this might happen to you:
My husband just keeps delaying the installation of new batteries; despite the fact that I buy them, leave them out, and remind him.~ Deb
Did you know that smoke detectors lose their effectiveness over time?
Smoke Detector Shelf Life
The U.S. Fire Administration says most smoke detectors installed today have a life span of about 8-10 years. After this time, the entire unit should be replaced.
Tip: Write the date of purchase with a marker on the inside of your smoke detector’s (battery compartment) so you will know when to replace it. Some of the newer detectors already have the purchase date written inside.
Why Do Smoke Detectors Expire?
Someone asked why there’s a 10 year shelf life when the shelf life of 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 degradation of the electronic component sensors aging and/or the reliability thereof. Also, a dual sensor smoke alarm additionally includes a photoelectric sensor which may be degraded over time.
“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 also just plain start breaking down.”
About Smoke Detectors (Important!)
There are many different brands of smoke alarms available on the market but they fall under two basic types: ionization and photoelectric.
IONIZATION alarms sound more quickly when a flaming, fast moving fire occurs.
PHOTOELECTRIC alarms are quicker at sensing smoldering, smoky fires.
DUAL SENSOR alarms combine ionization AND photoelectric into one unit (recommended).
Because both ionization and photoelectric smoke alarms are better at detecting distinctly different yet potentially fatal fires, and because homeowners cannot predict what type of fire might start in a home, you might consider installation of both ionization and photoelectric or dual sensor smoke alarms.
Each type detects a certain type of fire better.~ Fire Fighter Brian
Ionozation detectors work better for quick moving/burning fires. Photoelectric, works better for smoldering/smoky fires.
Rather than “guess” or try to rationalize what type of fire you might have in YOUR home, where YOUR family lives, you would be better protected having detectors that do both! THAT’S why!
Also CO detectors (carbon monoxide). CO doesn’t rise like smoke. Just put them on each level/floor/part of your house that you live in, especially in or near the bedrooms, and you will be covered.
Best Dual Sensor Smoke Alarm:
The following smoke alarms are what I have installed in my own home. I have several of the AC (hardwired) units and I’ve also added a few battery powered smoke alarms in other locations.
I thought my dual smoke detectors worked fine because every time i made toast they would go off! Everyone joked it was an automatic dinner bell!~ a MSB commentator
But then my dishwasher caught fire. There was smoke hanging 3 ft. off the ceiling and flames shooting out from under the cabinet!
CRICKETS! Not a sound out of any of them! (but they went off again the next day when i was broiling) Batteries – good. Test button – works! The smoke detector was 7 yr. old. We immediately replaced all of them.
PLEASE REPLACE OLD DETECTORS! You can’t trust them.
Fire Escape Plans
You should have escape plans and make sure everyone in the household knows them.
Have several fire extinguishers!
Consider one in the bedroom and one near the kitchen (at least!).
Clarification: I (and many of us) use the terms Smoke Detector and Smoke Alarms interchangeably. Although they aren’t technically the same thing.
“Smoke Detectors” are connected to an Alarm Control Panel, installed by an alarm company, inside a residence or in a multi-family dwelling with a large commercial Fire Alarm Control Panel. Apparently if this is the case, the 10 year replacement rule does not apply, unless the manufacturer says otherwise.
The rest of us typically have 120vac interconnected “Smoke Alarms”, that must to be replaced every 8-10 years. Just saying…