The Best Smoke Detectors of 2021

Protect your loved ones with the first line of defense against fire and other dangers in your home.

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The Best Smoke Alarm Options

Photo: Tom Scalisi

Smoke detectors are a lot like income taxes: You need to deal with them once a year, not a whole lot of people understand them, and issues with either can be particularly, well, alarming. Simple yet essential heroes of home safety and security, smoke detectors tend to be forgotten until they go off (a good thing) or until they fail to function properly in an emergency (a potential tragedy).

The National Fire Protection Association recommends installing at least one smoke detector for each floor of your home, as well as one in every bedroom. So it’s important to become familiar with the different types of detectors and how each type operates, as well as some of the finer points of smoke detector technology. Even if you don’t think you’re in the market for a new model right now, you very well might be after reading this article.

As the first line of defense against a house fire—and, in many cases, a guard against carbon monoxide as well—smoke detectors protect those in your home 24/7. I personally did hands-on tests of the models below to help you choose one that you can trust to protect yourself, your loved ones, and your home.

  1. BEST OVERALL: First Alert SA320CN Dual-Sensor Smoke and Fire Alarm
  2. BEST BANG FOR THE BUCK: Kidde Smoke Detector, Battery Powered
  3. BEST IN TECH: Google Nest Protect – Smoke Alarm – Smoke Detector
  4. BEST INTERCONNECTED: Kidde Wireless Smoke Detector, Interconnected
  5. BEST VOICE ALARM: Kidde Smoke & Carbon Monoxide, Voice Alert
  6. BEST DUAL SENSOR: X-Sense Smoke and Carbon Monoxide Detector Alarm
  7. HONORABLE MENTION: First Alert Combination Smoke and Carbon Monoxide
  8. ALSO CONSIDER: First Alert Z-Wave Smoke Detector & Carbon Monoxide
The Best Smoke Alarm Options

Photo: Tom Scalisi

Types of Smoke Detectors

There are three main types of smoke detectors: photoelectric, ionization, and dual sensor. While they all do the same job, they go about it differently.

Photoelectric

The chamber of a photoelectric smoke detector contains an LED light, which shoots a beam across the chamber, and a sensor that sits approximately 90 degrees from the LED. Under normal conditions, the sensor can’t “see” the LED beam, but when smoke enters the chamber, the light reflects off smoke particulates and the sensor detects the beam.

The instant the sensor detects the beam, the alarm activates. Photoelectric smoke detectors are most effective at detecting smoldering burns—barely burning fires that can, frighteningly, smolder for days before becoming a bigger issue.

Ionization

Though these detectors employ radioactive materials, alpha rays, and other seemingly sci-fi technology, they operate on a fairly simple premise: A chamber fills with tiny particles called ions, held in place by electrical charges. A sensor in the chamber knows how many ions are contained within. When smoke enters the chamber, it removes some of the ions, affecting the sensor’s count and sounding the alarm. Ionization smoke detectors are most effective against fires that are actively flaming.

Dual Sensor

Just as the category name suggests, these detectors use both types of sensors. There’s no winner in a race against photoelectric and ionization detectors, and they each have their own strengths. The use of both sensor types means faster detection of threats across the range of different materials that could be burning.

Key Shopping Considerations

Even if tested annually, a smoke detector has an operational lifespan of only 10 years. A model older than that should be replaced, regardless of its working condition. To help make an informed decision, here are some features to be familiar with when considering the wide range of models currently on the market 

Hardwired vs. Battery Operated

Battery-operated models, which tend to cost less, are usually stand-alone detectors. This means an activated smoke detector cannot alarm a monitoring system or other sensors in the home; only the detector in the smoky area will sound an alarm. The exception would be battery-operated models that are part of a home security system.

Hardwired smoke detectors install directly to the electrical system of the home. When one sounds an alarm, typically all of the detectors follow suit. While this may make it harder to pinpoint the unit that actually detected the issue, it alerts everyone in the house to danger, which is undeniably a considerable asset.

Most residential hardwired detectors now use battery backups, so even if the power goes out, the home will still have some fire safety protection—and that’s the best of both worlds. In commercial applications, things work a bit differently, in that the fire alarm panel will rely on the batteries to keep the alarm system live until the generators kick on or the power comes back.

Interconnectivity

Briefly touched upon above, interconnectivity refers to smoke detectors’ ability to “talk” to each other, alerting the entire system to an issue. For example, if there were an electrical fire within the car in an attached garage, the entire system throughout the house would activate immediately.

Fires can double in size every 60 seconds, so if you were sleeping on the other side of the house, you might not hear a stand-alone detector activate in the garage. Interconnected detectors will make you aware of the issue, potentially before it’s too late.

Carbon Monoxide

In a similar circumstance, a car left running in the garage can produce fatal levels of carbon monoxide, which could prove particularly dangerous to folks sleeping in a bedroom above. Smoke detectors with carbon monoxide sensors add another level of safety. While all homes should have carbon monoxide detectors, homes with gas or oil heat and hot water are particularly vulnerable.

Monitoring

Interconnected detectors are often part of a monitored home security system. The great benefit to these systems is they can alert the local fire department, even if no one is at home to make the emergency call. A carbon monoxide issue could render those inside unable to call the fire department, so the monitoring company can make that call, possibly saving lives.

UL Listing

Quality smoke detectors are Underwriters Laboratories (UL) listed. This certification ensures that the detectors meet UL’s stringent testing requirements. Given the importance of purchasing the best smoke detector system that a household can afford, it’s not worth the risk to install anything that isn’t UL listed.

Smart Features

For those interested in the latest fire safety technology, some detectors do boast smart features. Many of these detectors not only communicate with an overseeing alarm system but also with users’ phones through Wi-Fi. Some models even allow you to use any TV remote to mute an activated detector.

Our Top Picks

These top picks include photoelectric, ionization, and dual-sensor smoke detectors to suit a variety of different needs. All are quality models currently on the market that I tested personally, in the hope that my fair and honest opinions will help streamline your search for the best smoke detector.

Note: All of the following products feature battery operation, making them very easy to install. They’re also all UL-listed for safety.

Best Overall

The Best Smoke Detector Option: FIRST ALERT Dual-Sensor Smoke and Fire Alarm
Photo: walmart.com

Balancing features, reliability, and affordability, the First Alert SA320CN Dual-Sensor Smoke and Fire Alarm is a high-quality model that’s hard to beat. This model features an easy-to-clean photoelectric smoke detector in combination with an ionization sensor for detecting both fast-burning and slow, smoldering fires. Users can install the mounting plate on a wall or a ceiling without obstructing access to the AA battery compartment. While this smoke detector doesn’t interconnect with other devices or communicate with a monitoring system, it has a loud 85-decibel siren that residents will be able to hear throughout most homes.

During testing, I found the First Alert SA320CN Dual-Sensor Alarm to be easy to install. Also, the combination sensors activated quickly under smoke conditions, and it was plenty loud. Unfortunately, I wasn’t able to silence it despite numerous attempts. I also found the battery drawer a little awkward to access, though that should only be an issue once a year during battery changes.

Product Specs

  • Type: Combination (photo and ion)
  • Interconnect: No
  • CO2: No

Pros

  • Very easy to set up
  • Alerted quickly during testing
  • Combination sensors

Cons

  • Refused to silence
  • Pull-out battery drawer is a bit awkward


Best Bang for the Buck

The Best Smoke Detector Option: Kidde 21026051 Smoke Detector Alarm
Photo: amazon.com

A hardwired, Wi-Fi, or interconnected fire alarm system can be expensive, but thanks to the affordable price of the Kidde i9050, users can equip the entire home for smoke detection without burning out the bank account. Though hardly a high-tech option, this basic ionization-style model, which runs on a 9-volt battery, is a reliable option for smoke detection.

Considering the budget-friendly price, I was skeptical about how well this alarm would test. While it did perform roughly 10 seconds slower than other devices, it alarmed within 25 seconds, and the siren was loud. Also, I was able to silence this alarm much faster than devices that cost four times the price. In my opinion, it truly offers the best value for dollar of any detector on the list, though it doesn’t offer many special features.

Product Specs

  • Type: Ionization
  • Interconnect: No
  • CO2: No

Pros

  • Affordable
  • Loud alarm
  • Silenced immediately

Cons

  • Roughly 10 seconds slower to alert than other devices


Best in Tech

The Best Smoke Detector Option: Google S3003LWES Nest Protect-Smoke Carbon Monoxide
Photo: homedepot.com

Equipped with the latest technology available today, the Google S3003LWES Nest Protect smoke and carbon monoxide alarm ties into existing hardwired systems and features Wi-Fi communication. Users can program the alarm to tell exactly where in the home an activation is taking place through both the Nest app and the built-in speaker. It uses dual-sensor technology to detect both smoldering burns and flaming fires.

In my test, I found the Nest Protect’s voice activation to be clear and the alarm to be fast. I also liked the appearance of this device, and appreciated that the baseplate offers quite a bit of rotational adjustment to ensure that it is straight when installed. Connecting the detector to the Nest app took a couple of tries, though.

There’s a larger caveat regarding this product and similar models that work with smart-home systems: Their compatibility with those systems depends on app updates, which means users must remember to keep up to date on apps. If the app is an old version, the detectors might fail to communicate with a smartphone or central monitoring service.

Product Specs

  • Type: Split-sensor which acts as both photoelectric and ionization
  • Interconnect: Yes
  • CO2: Yes

Pros

  • Crystal clear voice instructions
  • Reports to a phone app
  • Better looking than other detectors
  • Silenced quickly

Cons

  • App a bit tricky to connect to the device
  • Must remember to keep app updated


Best Interconnected

The Best Smoke Detector Option: Kidde Wireless Interconnect Smoke Detector
Photo: amazon.com

Older homes without pre-existing fire alarm wiring may be best served by the Kidde RF-SM-DC Wireless Smoke Detector with interconnection. This model can provide interconnecting coverage without expensive wiring or smart-home apps. These simple battery-operated units use three AA batteries to communicate with each other through radiofrequency, rather than Wi-Fi.

When one detector activates, it signals the others through radio waves, causing a fast chain reaction of alarms. The downside is that fluctuations outside the temperature range of 40 to 100 degrees can cause false alarms and lead to premature battery failure. However, with a few of these units, even such areas as detached garages and sheds can connect for protection.

Though I only tested one device, these smoke detectors operate in a very simple way that’s unlikely to fail: They feature a set of dip switches on the back, and all the user must do is ensure the switches on all the devices match to get them all to activate at once. In my testing I found that the device activated quickly and was easy to silence. Locking it to the base took a few tries, unfortunately, because it wasn’t especially intuitive.

Product Specs

  • Type: Ion
  • Interconnect: Yes
  • CO2: Yes

Pros

  • Very fast activation
  • Easy to hush or silence
  • Wireless interconnect without an app or hub

Cons

  • Took a few tries to lock it onto the base


Best Voice Alarm

The Best Smoke Detector Option: Kidde 21026043 Battery-Operated Combination
Photo: amazon.com

When a traditional smoke detector siren starts, panic and confusion can set in rather quickly. To help alleviate some of the stress, Kidde’s 21026043 Battery Powered Combination Alarm sounds clear, easy-to-understand alerts for residents. The detector will repeat “Fire,” “Warning: carbon monoxide,” or “Low battery” for the corresponding condition, offering a clear indication of the hazard at hand.

This combination detector alerts to both smoke and carbon monoxide. It also has an easily accessed battery compartment on the front for quick battery changes. And though this unit doesn’t interconnect with other devices, it sounds an 85-decibel alarm that should be loud enough to alert everyone in the house.

During testing, I found this Kidde model to perform very well. The front-access battery compartment is simple, and the back of the unit features a handy guide to determine which codes the flashing lights might be alerting to. I also considered the ratcheting base to be well designed, as it allowed for flexible positioning even after securing the base. My only complaint was that it took four tries to silence the alarm.

Product Specs

  • Type: Ionization
  • Interconnect: No
  • CO2: Yes

Pros

  • Handy alarm-light guide on the back
  • Clear voice directions
  • Well-designed ratcheting base

Cons

  • Didn’t immediately silence


Best Dual Sensor

The Best Smoke Detector Option: X-Sense 10-Year Battery Smoke and Carbon Monoxide
Photo: amazon.com

When it comes to protecting a home against both fire and carbon monoxide, look to the X-Sense 10-Year Battery Smoke and Carbon Monoxide detector. It features a photoelectric smoke sensor and an electrochemical carbon monoxide sensor that operate independently of each other, offering as much detection as possible in an emergency.

The X-Sense features an LCD display to help take out the guesswork. It indicates the CO2 in parts per million (PPM), as well as the remaining battery life, to keep users up to speed on the condition of their home’s air at all times. This unit also has a 10-year battery life, which means users needn’t worry about changing batteries for a full decade.

I was eager to try the X-Sense as it looked great and the brand has been receiving a lot of positive attention lately. My first impression was the device is well built and attractive, and that the alarm was incredibly loud. During testing, it was initially easy to set up and it activated almost immediately under smoke conditions. However, it was difficult to silence (taking several attempts), and I broke the “on/off/disable” switch on the back. I honestly don’t understand why this feature exists, and I would caution users not to touch it.

Product Specs

  • Type: Photoelectric with carbon monoxide
  • Interconnect: No
  • CO2: Yes

Pros

  • Extremely loud
  • Near-immediate response
  • Digital screen for CO2 readings

Cons

  • Had to silence it repeatedly
  • I broke an unnecessary feature


Honorable Mention

The Best Smoke Detector Option: First Alert Combination Smoke and Carbon Monoxide
Photo: amazon.com

Anyone on the hunt for an affordable combination smoke and carbon monoxide detector should check out the SCO5CN combination from First Alert. This device features an electrochemical carbon monoxide detector as well as a photoelectric smoke sensor, activating an 85-decibel alarm when either sensor triggers.

One of the best aspects of testing the First Alert SCO5CN was its simple, fast setup. While it does suffer from the same goofy pull-out battery drawer as other First Alerts, mounting it to the ceiling was a breeze. Also, the siren was loud and clear when alerting under smoke conditions. Again, as I found with other First Alerts, the unit refused to silence.

Product Specs

  • Type: Combination photoelectric smoke and electrochemical CO2
  • Interconnect: No
  • CO2: Yes

Pros

  • Very loud siren
  • Easy to install
  • Combination smoke and CO2

Cons

  • Would not silence
  • Awkward battery drawer


Also Consider

The Best Smoke Detector Option: First Alert Z-Wave Smoke Detector & Carbon Monoxide
Photo: amazon.com

First Alert’s Z-Wave Smoke Detector and Carbon Monoxide Alarm is worth considering by those who want to set up their own interconnected system that they can access from a phone and other devices. This combination smoke detector interfaces with the Ring Alarm hub and app, offering users real-time alerts wherever they have internet service. This unit features a photoelectric smoke sensor and an electrochemical carbon monoxide detector to alert under a variety of conditions.

Like most First Alert devices, the Z-Wave Smoke Detector and Carbon Monoxide Alarm was very easy to install. The audible alarm was very loud, and it activated faster than I could reach for my stopwatch. The only issues I experienced when testing were its refusal to silence it (a common problem with First Alert) and, obviously, if you don’t have a hub, this will only work as a basic combination detector.

Product Specs

  • Type: Combination photoelectric smoke and electrochemical CO2
  • Interconnect: Yes, via Ring hub
  • CO2: Yes

Pros

  • Easy to install
  • Loud
  • Fastest activation in test

Cons

  • Refused to silence
  • Requires Ring hub for full use


Our Verdict

Smoke detectors are essential safety devices that no home should be without, so anyone looking for an all-around capable unit with dual-sensing technology should check out the First Alert SA320CN Dual-Sensor Smoke and Fire Alarm. Those who want smart technology, however, might agree that the Google Nest Protect is the most advanced home smoke detector on the market.

How We Tested the Best Smoke Detectors

While pressing the “test” button is a perfectly fine way for folks to perform once-a-month testing of a smoke detector, that cannot tell the whole story of how well a unit will perform. A lot more went into our testing and, as someone who’s spent nearly a decade working with commercial fire alarms, this assignment was right in my wheelhouse.

I installed each of these devices one by one, according to the directions, to determine how easy they were to set up. I also tested each device by spraying two puffs of canned synthetic smoke—the same type I used when testing fire alarms professionally. I timed each to get a solid sense of how long activation took, and then compared the results.

FAQs

Now that you know a bit more about the best smoke detectors, some questions may still pop up. Here are answers to some of the most frequently asked questions, so check below for the information that will clarify your queries.

Q. How often should I test my smoke detectors?

The U.S. Fire Administration (USFA) states that you should test your smoke detectors monthly and replace the batteries at least once a year.

Q. How many smoke detectors should I have?

The National Fire Protection Association recommends that homes should have smoke detectors installed in every bedroom, a common area outside the sleeping area, and on every level (including the basement and attic).

Q. Are smart smoke detectors better?

Smart smoke detectors provide a bit of extra awareness, particularly if no one is at home when the issue occurs. However, they’re not necessarily better. Some would suggest that having a hardwired system tied into a central monitoring service is the best option.

Q. How do I stop my smoke detector from beeping?

Most smoke detectors feature dual-purpose test and “hush” buttons that will allow the user to test their detector’s functionality but also stop it from sounding an alarm. However, if your smoke detector is simply beeping, it probably just needs a battery change.