The 8 Best Smoke Alarms

Updated April 21, 2018 by Gregg Parker

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We spent 44 hours on research, videography, and editing, to review the top options for this wiki. Nothing is more precious to you than your family, and nothing is more expensive than your home. Protect them both with one of these smoke alarms, some of which also monitor for deadly carbon monoxide levels as well. Some choices even offer Wi-Fi connectivity, so you can access them remotely from anywhere in the world. When users buy our independently chosen editorial picks, we may earn commissions to support our work. Skip to the best smoke alarm on Amazon.

8. Kidde i9050

If you just want a basic smoke alarm, you can't do much better than the Kidde i9050. It has a low-battery indicator that chirps whenever it needs to be replaced, and uses an ionization sensor to alert you of fires. At less than $15, it's a real bargain.
  • 85 decibels at 10 feet away
  • 10-year warranty
  • does not detect carbon monoxide
Brand Kidde
Model 21026051
Weight 5.6 ounces
Rating 3.9 / 5.0

7. First Alert BRK 7010B

The First Alert BRK 7010B is an economical choice, at less than $20, and works via a photoelectric sensor. It can be connected to other First Alert hardwired smoke and carbon monoxide alarms for complete home-wide coverage.
  • latching alarm indicator
  • single test-silence button
  • no ionization detection
Brand BRK Brands
Model 7010B
Weight 4 ounces
Rating 4.2 / 5.0

6. CooWoo Battery Powered

For a unit that works right away, take a look at the CooWoo Battery Powered. It comes with a 9-volt battery and has a large test button, so you can always make sure it's working, something any homeowner should do once a month just to check.
  • blinking power light
  • 85 decibel alarm
  • doesn't have an ionization sensor
Model GS528A
Weight 6.4 ounces
Rating 4.1 / 5.0

5. Kidde KN-COPE-I

The Kidde KN-COPE-I emits a beeping tone followed by a voice warning to clarify whether it detected smoke or carbon monoxide. It also has a front-loading battery door that is easy to access, which will be a relief when it comes time to replace the included 9-volt battery.
  • both heat and photo sensors
  • backed by 7-year warranty
  • does not include mounting hardware
Brand Kidde
Model 21007624
Weight 12 ounces
Rating 4.1 / 5.0

4. Leeo Smart Alert

The Leeo Smart Alert works with your existing smoke alarms and alerts you via your Android or iOS device if one is triggered. It can be set up to contact friends or family if you don't respond within a certain time period, and you can call 911 directly from the app.
  • doubles as a nightlight
  • 16 million light color options
  • takes two minutes to set up
Brand Leeo
Weight 8.8 ounces
Rating 4.7 / 5.0

3. First Alert BRK 3120B

The First Alert BRK 3120B is a hardwired option that has a backup battery, so it will still work if the power goes out. It features dual photoelectric and ionization smoke sensing technologies, and at 85 decibels, it's loud enough to be heard throughout the house.
  • easily silence low battery chirp
  • comes with mounting bracket
  • power source indicator lights
Brand First Alert
Model 3120FF
Weight 13.6 ounces
Rating 4.6 / 5.0

2. Kidde KN-COSM-BA

The Kidde KN-COSM-BA is a standalone voice warning system that issues alerts for fire, carbon monoxide concentration, and a low battery. The talking feature eliminates guesswork and confusion when seconds count. It also has a smart hush button.
  • front loading battery door
  • led indicates it's operating
  • one button to test or silence it
Brand Kidde
Model 21026043
Weight 14.4 ounces
Rating 4.8 / 5.0

1. Nest Protect 2nd Generation

The battery-powered Nest Protect 2nd Generation keeps you abreast of what's happening in your home no matter where you are. It connects to Wi-Fi, and will send alerts directly to your phone if it detects smoke or carbon monoxide.
  • can also send low battery alerts
  • tells where the problem is located
  • can turn off the alarm remotely
Brand Nest
Model S3000BWES
Weight 1.8 pounds
Rating 4.6 / 5.0

Two Ways To See The Smoke

The image you're looking at is a rough peek at the layout inside of an ionization smoke detector. These, along with photoelectric smoke detectors are your best bets for detecting a fire in your home, but each one has its advantage over the other.

In the ionizing smoke detector, you're installing a small radioactive device in your home. But don't worry; your pregnant cat isn't about to give birth to a three headed kitten who speaks Spanish. It's not that kind of radiation.

Within the housing of an ionizing smoke detector is a small amount of Americium-241, a radioactive isotope that emits alpha particles throughout a plastic chamber.

The good news here as far as your safety goes is that alpha particles are pretty weak, too weak, in fact, to penetrate the plastic of the chamber, and weaker still when exposed to a large area. You'd have to break open the chamber and rub the Americuim-241 all over your eyeballs to get a negative effect.

Anyway, as the material decays its alpha particles ionize the oxygen and nitrogen in the air, the resulting positively charged atoms and negatively charged electrons of which are drawn to two leads in the compartment, each of which is charged either negatively or positively.

That creates a nice little current. When smoke, or steam, or excessive heat enters the chamber, it interferes with the ionization process, reducing the current, which sets off the alarm. That makes ionization smoke detectors ideal for detecting flash fires, kitchen fires, and any other fire that produces a lot of heat, without necessarily producing a lot of smoke.

Photoelectric sensors, on the other hand, require no radioactive materials. While that doesn't make a real difference in their safety considering the relative safety of Americium-241, it does mean that they don't require any special disposal the way ionizers do.

Instead of relying on ionization, photoelectric smoke detectors use LEDs to send a beam of light across the top of a T-shaped tube. At the bottom of the T is a photo cell that detects the base amount of light leaking down the stem of the T.

When smoke enters that chamber, its particles reflect a lot more light down the stem and onto the photo cell. That increase in light hitting the sensor sets off the alarm.

A design like this makes a photoelectric smoke detector ideal for picking up slow smoldering fires like the ones started by cigarettes or the one burning inside you whenever you think of your in-laws.

Fire In The Hole!

So, you know how each of the two types of smoke alarms works, but that might not yet have cleared up the burning question: which kind should you buy?

I'll make it easy for you. You actually need both.

I'm not saying that you absolutely have to have both kinds of smoke detectors at every detection point in your home, although that would be the safest way to set them up.

At the very least, take a look around your home to evaluate the different types of fires that are likely to spark up in each, and determine the best kind of alarm for that area.

Since ionization smoke detectors are best suited for picking up big, flashy fires, the kitchen seems like an obvious choice for one of those. Electrical fires can get high and hot very fast as well, especially if they start in a wall with flammable insulation, so anywhere that you're challenging the electrical load of a circuit (by your entertainment center, for example) would be a good place for an ionizer.

You'll want to place your photoelectric sensors anywhere a smoldering fire would take place, as well as anywhere people might be sleeping. Since the majority of fire-related deaths result from smoke inhalation, the extra time it'd take for an ionization detector to wake you up during a slow, smokey, smoldering fire might cost you your life.

The One Time Smoking Saved Lives

The story goes that a Swiss physicist named Walter Jaeger was working hard on a device that could detect poisonous gasses.

This was back in the late 1930s, after gaseous chemical warfare had been unleashed in WWI.

His idea was simple: he thought that gas particles would disrupt the ionization process of a radioactive isotope in an airy chamber, altering the current of two leads. Sound familiar?

Well, as his experiments failed to produce an alarm, Jaeger sat down and sadly lit a cigarette. You can guess what happened next. The alarm went off, and Mr. Jaeger realized that he had accidentally invented the modern smoke detector.

The early 70s saw both the commercialization of the ionization smoke detector and the introduction of the first optical photoelectric smoke detectors, both of which dominate the market to this day.

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Last updated on April 21, 2018 by Gregg Parker

Gregg Parker is an author, screenwriter, and comedian who divides his time between Los Angeles, California, and Osaka, Japan. When he’s not watching sports, he spends most of his free time on his artistic pursuits or collecting miles for his next international journey.

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