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The First Alert SMI100 is a battery-operated smoke alarm featuring advanced Precision Detection technology that minimizes false alarms while providing early fire warnings. Its user-friendly design includes a front-access battery compartment, a test/silence button for easy maintenance, and an end-of-life alert to ensure continuous home safety. Ideal for quick installation and reliable protection, it’s a top-rated choice for modern households.











| ASIN | B0CJMP7WHH |
| Alarm | Smoke Alarm |
| Best Sellers Rank | #39 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #1 in Smoke Detectors & Fire Alarms |
| Brand | First Alert |
| Built-In Media | 9V Alkaline Battery |
| Color | White |
| Customer Reviews | 4.5 4.5 out of 5 stars (3,996) |
| Item Dimensions D x W x H | 5.4"D x 5.4"W x 1.9"H |
| Item Type Name | Smoke Alarm |
| Item Weight | 0.7 Pounds |
| Manufacturer | Resideo |
| Model Number | SMI100 |
| Number of Items | 1 |
| Operating Humidity | 10-95% RH |
| Power Source | Battery Powered |
| Product Style | Precision Detection |
| Sensor Type | Ionization |
| UPC | 029054022387 |
| Unit Count | 1.0 Count |
J**N
Reliable Smoke Alarm That Was Quick and Easy to Install
I recently purchased the First Alert SMI100 smoke alarms and I’m really happy with them. Installation was incredibly easy since they are battery operated, so there was no wiring needed. I had both alarms mounted in just a few minutes. The design is simple and clean, and the front battery compartment makes it easy to change the battery without taking the whole unit down. I also like the test/silence button on the front because it makes testing the alarm quick and simple. The alarm itself is loud enough that you would definitely hear it throughout the house, which is exactly what you want for safety. The detectors use updated sensing technology designed to give early warning of fires while reducing nuisance alarms from things like cooking smoke.Overall, these smoke alarms give me peace of mind knowing my home has reliable protection. They were affordable, easy to install, and work exactly as expected. I would definitely recommend them to anyone looking for a simple and dependable smoke alarm.
K**S
As described. Great quality.
These aren't interconnected, and are powered by battery only. But they do the job as described and are a lower cost option to replace the more costly interconnected "wired" models.
E**T
Reliable and loud
So far so good, we've had these fire alarms for about a year now and the one near the kitchen we replaced the batteries about 6 months ago, and the other one we just did for the first time. The one near the kitchen has been triggered a few times due to various baking mishaps so that makes sense I guess, definitely loud enough to wake you if necessary. Its a bit of a pain to change the batteries but that's life. Seems to be reliable and that's all I really care about. Install was simple enough.
C**Y
Works great, quality of the body is meh
A great, cheap option for a smoke detector! Installed onto the wall super easy. One issue, is the battery compartment can catch when trying to install the battery, but a little pressure and it clicks into place (without breaking any plastic, thankfully).
F**A
Easy and effective.
These are perfect. Easy installation and easy to monitor 👌.
I**N
Will wake you and your kids if there is a fire
This First Alert smoke alarm is clearly the standard. Works reliably, is a powerhouse in a small size. It can be installed easily with a simple nail or screw without using the wall attachment materials included. It has a very loud piercing notification signal which is exactly what I needed to wake kids out of bed and get them started on how I have trained them if there is a fire. This unit was a replacement for a unit I have had for nearly 10 years. These smoke alarms are reliable.
N**F
Replaced Exp First Alert Smoke Detectors w/New
I just installed these 2 First Alert smoke detectors, so I can’t give you a long time use review, but I’m happy with my purchase. These replaced two 10 year-old similar First Alert smoke detectors that had reached their expiration date. I was very pleased with those, which is why I looked for the same smoke detectors. I couldn’t find the exact same ones, so I replaced with these, which look similar and are basic like the first pair. Although the size of the new ones are a little bit smaller than the ones they replaced, I was pleased to find that the new brackets fit the 2 screws I already had in the walls from the old ones. I was concerned that I would be patching and drilling, but I didn’t have to, so installation was easy peezy. The other thing that is different on the new ones is that the batteries are 9 V versus the AAs for the old ones. I prefer AAs because it’s a battery that I always have around the house and they are easy to come by and inexpensive, relatively speaking. However, the new detectors came with batteries, so I don’t have to worry about replacing them for another year.
S**E
A Steady Reliability .
I've been using this brand for decades and I'm glad they took things to a little higher level for the most basic even though it costs a little more . For some reason the ones I have that were the old basic unit would last about 3 years then start beeping like the battery was dead even with a new battery , thus needed to be replaced . This unit is easier to blow off the sensor and hopefully that'll help it last longer . Nothing more annoying than that irregularly timed beep at oh dark thirty and not knowing which one it is because of the irregularity of when it beeps . I have a smoke detector in every bedroom, laundry , kitchen, den and hallways for a total of 8 in the home. Not knowing which one needs attention sucks . This one did need for me to change the frame it fits in but the screws stayed in the same spots so it was super quick to change out .
Trustpilot
1 day ago
1 month ago