Best Smoke Detectors of 2019 Review

According to the United States Fire Administration (USFA), three out of five residential fire deaths result from fires in properties without working smoke alarms, and more than a third of residential fire deaths result from fires in homes where no smoke alarms are present at all. This means that if your home has a working smoke detector, your risk of death in a residential fire gets cut in half.

Although smoke detectors often seem like nuisances that randomly go off when there’s no fire and chirp all through the night when the batteries are low, they are an essential part of your home security that need to be maintained, updated, and replaced periodically.

Best Smoke Detectors of 2019

  • Nest Protect (2nd Generation)
  • BRK 7020B Photoelectric Smoke Alarm
  • First Alert BRK 3120B
  • Kidde KN-COSM-BA/IBA Alarms

Types of smoke detectors

There are three types of smoke detectors on the market: ionization, photoelectric, and dual-sensor alarms, which use both ionization and photoelectric technology.

Ionization smoke alarms

Ionization smoke alarms are best at detecting the small particles typical of the smoke from fast, flaming fires—as opposed to smoldering fires, which produce smoke with larger particles. Ionization smoke alarms hold a small amount of radioactive material (Americium-241) between two electrically charged plates, which ionizes the air and creates a current between the plates. When smoke enters the chamber, it disrupts the current and activates the alarm.

Ionization smoke alarms can be triggered by the smoke produced by burnt food or by steam from a the shower, so you may get more false alarms if the alarm is placed in the kitchen or near a bathroom.

Photoelectric smoke alarms

In a photoelectric smoke alarm, a light source is aimed into a sensing chamber at an angle away from the sensor. When smoke enters the chamber, the light is defracted and reflected onto the light sensor, which triggers the alarm. These types of smoke detectors are best at sensing smoldering fires that create a lot of smoke without many (or any) visible flames. While not as prone to false alarms as ionization smoke detectors, photoelectric alarms may be randomly set off by a buildup of dust in the unit.

Dual sensor smoke alarms

Dual sensor smoke alarms combine ionization and photoelectric sensors into one unit. Some models require both sensors to be triggered before the alarm will go off, but this may delay the alert from sounding. Other models only require one of the sensors to be tripped, but that also creates the potential for more false alarms.

Things to consider before buying

In addition to the type of smoke detector, there are several other safety features that should be taken into consideration.

Power source

Alarms can either be battery-powered or hardwired into your home’s electrical system with backup batteries in case the power goes out. Hardwired alarms are the recommended option (and are sometimes required by state law). Though they generally require professional installation, the safety advantage is that they can be interconnected with the other smoke alarms in your home.

Battery-only alarms are easy to install and they’ll continue to work during a power outage, but the batteries will need to be replaced once or twice a year. Some models use lithium batteries, which may last for up to the life of the alarm. Some alarms can be plugged into an outlet, but the ideal placement of an alarm is on or near the ceiling.


As mentioned above, you can link some smoke alarms, as well as carbon monoxide (CO) detectors, to all the units in the house so all of them will go off if one is triggered. This is an important feature for homes with multiple levels where you may not be able to hear an alarm in a far corner of the house. Many newer homes have this wiring already in place, or you can purchase alarms that will connect wirelessly.

Silence button

Being able to silence an alarm with a button is much better than disabling the unit—since then you decrease your chances of forgetting to put the batteries back in the unit. The silence button is a temporary measure and the alarm will sound again if whatever triggered it persists.

Some smoke alarms have one silencing button while others have two—one for a false alarm and one for a low-battery warning. The low-battery warning can be silenced for longer stretches of time than the regular alarm, but it varies from model to model.

Light alarms

A flashing light as part of a smoke alarm’s warning system is an important feature for anyone who is hearing-impaired. Some alarms also come with a safety light that provides illumination in the dark.

Digital CO display

Some smoke alarms also act as CO detectors, which are another important part of your home’s overall safety. Having a digital display of the CO levels, even when the concentrations are below the level that triggers the alarm, is extremely helpful, though not necessary for a product to be considered safe. Some CO detectors also show the peak CO level since the last reset, which lets you know if there were any spikes while you were away from the house or sleeping.

What the pros suggest

While there is value in having ionization or dual smoke detectors in your home, we recommend using primarily photoelectric smoke alarms throughout your house for two main reasons.

First, the majority of residential fire fatalities are due to smoke inhalation, which most often occurs at night when sleeping residents aren’t alerted to the presence of smoke. Tests show that photoelectric alarms will detect certain types of smoke much more quickly than ionization alarms. In the words of an official study performed by the National Institute of Standards and Technology (NIST), ionization smoke alarms provided a “somewhat better response” to flaming fires, while photoelectric alarms provided a “considerably faster response” to smoldering fires. The difference could be crucial, and the International Association of Fire Fighters (IAFF) agrees. It stated its official position on the issue in 2008 and reaffirmed its recommendation to use photoelectric smoke detectors in 2011.

Second, people are more likely to ignore or disable smoke detectors that emit a high number of false alarms or persistent low-battery chirps. Not having a working smoke alarm is worse than not having a particular type of smoke alarm, so anything that can prevent smoke alarms from being disabled will contribute to the overall safety of the device. Ionization alarms are more likely to be set off by burned food or steam from the shower and are therefore more likely to be disabled or ignored, making photoelectric smoke alarms a safer option.

We want to note that the USFA recommends using both types of alarms or dual-sensor alarms throughout the home because it’s impossible to say that one type of alarm will always be better in every fire situation.

Overall Top Pick: Dual-Sensor Photoelectric

Based on all of this information, we’ve selected a top overall recommendation: Nest Protect. The Nest Protect is a dual-sensor photoelectric smoke detector, which is unique in the household smoke detector industry and made it difficult to categorize into the tradition smoke alarm types. It comes with lots of impressive, user-friendly features and includes a carbon monoxide detector as well.

However, the $99 price tag per unit means that many people simply won’t be able to afford to install them throughout the entire house. That’s why we decided to give it our #1 overall recommendation but still include our top picks for each of the regular smoke alarm categories, plus a recommendation for a separate carbon monoxide detector just for good measure.

Nest Protect (2nd Generation)

Tech Specs

  • Price: $99
  • Size: 5.3 x 5.3”; 1.5” deep
  • Audio alert: 85 decibels
  • 2-year warranty
  • OS requirements: iOS 8.0 or later; Android 4.0 or later; Windows 7 or later; Mac OS 10.9 or later

Instead of using both photoelectric and ionization sensors like other dual sensor alarms, the Nest Protect has a “split-spectrum” sensor that uses a traditional infrared photoelectric sensor and a blue LED sensor. In effect, it protects against both types of fires by using the more reliable photoelectric technology, and it’s currently the only residential smoke detector on the market to do that.

The Nest Protect also includes an electrochemical carbon monoxide (CO) detector and heat and humidity sensors to differentiate between an actual emergency and false alarm triggers (like steam from the bathroom). There really aren’t any other dual sensor alarms that have a CO detector, but the Nest Protect manages to pack it all into its sleek design.

The other impressive feature of the Nest Protect is its wireless connectivity. You can perform a safety/connectivity check, silence false alarms, and receive notifications on your phone through the Nest app. The app is easy to set up—though users have reported some glitches, including lag time between the alarm going off and a notification on the phone. This can especially be a problem if you don’t have a reliable home wireless network or cell service. Nest products also require routers to support IPv6, and some routers are incompatible altogether.

Although the Nest Protect requires Wi-Fi to connect with your phone, it will still operate as a smoke detector if it loses connectivity; you just won’t get a notification on your phone. Both battery-powered and hardwired versions of the Nest Protect are available, both at the same price. The $99 price tag is the biggest drawback to this product. However, if it’s affordable for you, we can’t say enough how much we like the Nest Protect or how offers more than any other residential smoke detector on the market.


  • Dual photoelectric or “split-spectrum” sensor
  • Electrochemical CO detector
  • Sleek design
  • Alarm can be silenced from the app or by pressing the silencing button
  • LED lights and voice warnings for each situation
  • Helpful customer service
  • Interconnects with up to 18 devices
  • Integrates with Nest Learning Thermostat and Nest Cam
  • Heat, humidity, and ambient light sensors
  • Connects to your phone via Wi-Fi; periodically checks connectivity
  • Hardwired model with backup batteries available
  • Great reviews


  • 2-year warranty
  • Uses six AA batteries (battery-powered)
  • Relies on Wi-Fi to connect to your phone or tablet
  • May not connect to a router that doesn’t support IPv6

Best Smoke Alarm—Photoelectric : BRK 7020B Photoelectric Smoke Alarm

Tech Specs

  • Price: $48.99
  • Size: 5” diameter; 2.3” deep
  • Audio alarm: 85 decibels
  • 10-year warranty

The BRK 7020B meets all the mandated requirements for an effective smoke alarm, and though it doesn’t utilize advanced photoelectric technology or all the impressive features of the Nest Protect, it meets all of our standards at a much more accessible price. It is hardwired with a 9-volt backup battery in case of a power outage and can connect to up to 18 other BRK and First Alert devices. The advantage of having hardwired, connected devices is that all of them will sound if one of them is triggered.

Plus, a flashing light will let you know which alarm set the others off so you can address any concerns there. It also has a safety light that activates when the alarm is tripped, which sets it apart from many other alarms, including the BRK 7010B. BRK products comes with extensive customer support via phone, email, and online resources, so you will have plenty of help should any issues come up.


  • Safety light that activates when the alarm is tripped
  • Hardwired
  • Interconnects with up to 18 compatible BRK devices
  • Silence button will silence all connected alarms
  • Flashing LED light indicates which alarm was tripped
  • 9-volt backup battery included
  • Low battery alert
  • OptiPath 360 Technology provides direct access to the smoke sensor
  • Comprehensive customer support via phone, email, and online helps


  • Safety lightbulb cannot be replaced; however, it is covered under the warranty
  • May not be compatible with wiring in older homes

Best Smoke Alarm—Dual Sensor: First Alert BRK 3120B

Tech Specs

  • Price: $49.99
  • Size: 5” diameter; 2.3” deep
  • Audio alert: 85 decibel
  • 10-year warranty

Dual Sensor: First Alert BRK 3120BLike the Nest Protect, the First Alert BRK 3120B is a dual sensor alarm that uses photoelectric and ionization technology to sense both smoldering and flaming fires. It is also hardwired with two AA backup batteries and can connect with up to 18 devices, 12 of which can be smoke detectors. Unlike the Nest Protect, however, it doesn’t have some recommended safety features like a safety light or voice warnings. However, it is still a great product and is available at almost half the cost of the Nest Protect.

BRK products offer some unique features that give the smoke detectors added convenience and security. One is their patented OptiPath 360 Technology that provides 360 degrees of direct access to the smoke sensors, allowing any smoke in the air to reach the sensor more quickly. It also has two “latching” features that will use flashing LED lights to let you know which unit set off an alarm or needs a new battery. The vast majority of reviews are positive, confirming our conclusion that this is a great option at a reasonable price.


  • Uses both photoelectric and ionization smoke sensors
  • Interconnects with up 18 First Alert devices (including CO detectors and heat alarms)
  • Hardwired
  • Includes two AA backup batteries
  • Low battery alerts
  • Two silencing buttons—one for the alarm, one for the low-battery chirp
  • OptiPath 360 Technology provides direct access to the smoke sensor
  • Flashing LED lights identify which unit initiated an alarm or low battery alert


  • Older houses may not support the needed wiring
  • No emergency safety light

Best Smoke Detector—Ionization: Kidde KN-COSM-BA/IBA Alarms

Tech Specs

  • Price: $39.99 and $55.99
  • Size: 5.75” diameter; 1.7” deep
  • Audio alarm: 85 decibels
  • 10-year warranty

Ionization: Kidde KN-COSM-BA/IBA AlarmsAlthough the IAFF does not recommend using ionization smoke detectors on their own, we’ve included one in our top picks for those who want to cover all their bases with multiple types of alarms. The Kidde KN-COSM-BA/IBA models have great reviews and can double as carbon monoxide (CO) detectors, giving your family one more layer of built-in protection.

The difference between the two models is in the power supply—the -BA model is powered by three AA batteries, while the -IBA model is hardwired. Generally, we recommend using a hardwired model whenever possible; however, in this case the battery-powered model has a higher percentage of positive reviews (over 1,100 reviews on Amazon with a 4.5 average rating as of this writing), so it is included here as well.

The Kidde KN-COSM-BA/IBA models both have several security features that make them excellent picks. They have a silencing button that will hush the alarm for 10 minutes before checking the environment again, so you don’t need to take out the batteries if there’s a false alarm. When an alarm is triggered, they use several alert types: flashing lights, beeping, and a voice warning that specifies whether a fire or carbon monoxide is detected.

Plus, a peak memory feature of the CO detector will announce if it has sensed a CO level of 100ppm or higher since it was last reset (anything above 36ppm is considered excessive and cause for immediate action). All of these features work together to create two great options for combination ionization smoke detectors/CO detectors.


  • CO detector included
  • Flashing lights, alarm beeps, and voice warning
  • Low battery alerts
  • Test/reset button
  • Silence button
  • Peak level memory for CO detector
  • 7-year life for battery-powered; 10-year life for hardwired
  • Backup batteries included (hardwired model)
  • Interconnects with up to 24 Kidde devices (hardwired model)


  • No photoelectric sensor
  • No emergency safety light
  • Battery-powered (-BA model)

Carbon monoxide detector: An extra safety precaution

Because our pick Nest Protect smoke alarm includes a carbon monoxide detector, we wanted to provide an additional recommendation for a separate CO detector in case your smoke alarm does not include one. If your home uses any fuel-burning appliances such as a furnace, water heater, range, cooktop, or grill, you should have a CO detector. CO is produced anytime fuel is burned and if it builds up in a home, it can poison anyone breathing it. Having at least one CO detector is an important aspect of your home’s safety.

Best Carbon Monoxide Detector: Kidde KN-COPP-B-LPM

Tech Specs

  • Price: $34.99
  • Size: 4.5 x 2.75 x 1.5”
  • Audio alert: 85 decibels
  • 5-year warranty

Kidde KN-COPP-B-LPM Carbon Monoxide DetectorThe Kidde KN-COPP-B-LM is a top-rated CO detector with all the safety features you need to stay safe. It has a digital display that updates the current CO level reading every 15 seconds, and it also has a peak level memory that lets you know the highest concentration detected since the last reset.

CO alarms generally have a shorter lifespan than smoke detectors (5 to 7 years), and the Kidde KN-COPP-B-LM has a 7-year life but only a 5-year warranty. It can be either freestanding or mounted on a wall, giving you lots of options for placement. If you don’t have a combination smoke/CO detector, this is an excellent choice to keep your family safe from carbon monoxide.


  • Digital display
  • Updates every 15 seconds
  • Test/reset button
  • Peak level memory
  • 7-year life
  • Flashing LED light indicate status (green for normal, red for alarm)
  • Audible alarm for high CO levels
  • Low-battery alerts
  • Freestanding or wall mounted


  • Uses three AA batteries (included)—no hardwiring
  • 5-year warranty

How to keep your house safe

In addition to choosing a type of smoke detector, there are some additional guidelines for the maintenance, placement, and replacement of your alarms:

  • Make sure alarms are installed correctly
  • Replace alarms every 10 years
  • Test alarms once a month to make sure they are working
  • Replace the batteries once a year
  • Periodically vacuum out detectors to avoid dust buildup

The location of the alarms may be more important than the type or number. Experts recommend (and some states require) new houses to have a minimum of one alarm on every level of your home—including in the basement and near the attic, if applicable. Ideally, a smoke detector should be installed inside every bedroom and outside sleeping areas (for example, in the hallway leading to the bedrooms).

On levels that don’t have bedrooms, smoke alarms should be installed in the main living area (family room, den, etc.) or near the stairway to the upper level or both. Smoke alarms should also be placed at least 10 feet away from cooking appliances to avoid false alarms.

Smoke alarm requirements differ from state to state, so be sure to check the guidelines for where you live.

Bottom line: A necessary safety measure

Smoke alarms are not a perfect technology—though the Nest Protect comes awfully close—but having them in your home increases your security, regardless of which type or brand you use. We echo the recommendation of the IAFF and strongly suggest using photoelectric sensors as the primary smoke detectors in your home, but having multiple working smoke alarms throughout the house and at least one CO detector will increase your family’s overall security.

  • Tim Alosi

    Hi … from the FirstAlert / BRK site, the 7020B is discontinued. Can you recommend an alternative?