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The Best Smoke Detectors for 2025 (Take It From a Chemical Engineer)

I simulated real fire smoke at my home and tested out the best smoke detectors for you.

Choosing the right smoke detector is probably your most important home tech purchase. That’s because when it comes to a house fire, time is of the essence. That’s where some alarms fall short. Some are faster than others at detecting either a smoldering or a flaming fire.  

I’ve been working as a laboratory engineer for the last seven years developing and performing testing procedures for hundreds of tech products for CNET. I created a simulation of a real-life house fire smoke and found which smoke alarms are the fastest at detecting a fire emergency.  

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What is the best smoke detector overall?

My pick for the best smoke detector is the Kidde Dual Sensor Smoke Detector PI9010 because it performed better than its competitors during my home smoke test. The Kidde PI9010 was able to detect the two types of fires the fastest -- both smoldering and flaming smoke -- making it the most reliable smoke detectors available right now. My personal opinion is that Kidde is Bueno, Bonito y Barato. This is a common saying in Spanish that translates to good, pretty and cheap.

Best smoke detectors of 2025

Through my testing, I found the Kidde smoke detector to be better performer when it comes to fast detection. It has both sensor types: Ionization and photoelectric which is why it was bale to effectively detect both fire types quickly. What impressed me most is its ability to outperform its competitors for during the slow-smoldering fire test. Its slow-smoldering detection time of 24.1 seconds after initial exposure to smoke was the best time of all other smoke detectors. It performed second-best when detecting a fast-flaming fire, averaging 17.9 seconds. 

It's powered by a 9-volt battery, plate-mounted and features both "hush" and "test" buttons for weekly testing.

I liked its efficiency, reliability and affordable price. What I didn't like is its lack of smart home compatibility. But for me reliability was more important then smart features.

If you are looking for a high-tech device that you can control and communicate with, the Nest Protect is perfect for the task. It features a single button that has "hush," "test" and "reset" functionality, and you can hardwire it to a 120-volt circuit or run it on a battery.

It features two alert modes: Heads-up, characterized by a yellow glow in the background when smoke levels are rising, and Emergency, when the smoke concentration in an area has reached a critical level, displaying a red light. The device will speak to you in English, letting you know which area of your home needs immediate attention. This is particularly useful if you have a large home and need to know exactly where the emergency is located.

The Nest App allows you to interconnect other Nest Protect smoke alarms in your home, displaying them all in a single dashboard. From there, you can easily hush and/or test all or any of your smoke detector devices at the press of a button. Sensors, alarms, voice, battery level and Wi-Fi connectivity checks are all part of the assessment. 

The original Nest Protect ranked fourth in our quickness of response test, but its ample functionality, versatility and smart features make it a very compelling option for those looking to upgrade their smart home security game. 

Ranked third in both smoke tests, the First Alert Dual Sensor is a solid option at an affordable price. The silence/test button is stiffer than most other models, which can be a pain if you're trying to hush a false alarm or conduct a weekly test. But this budget option was able to detect fast a flaming fire in less than 23 seconds and a slow smoldering smoke in less than 34 seconds (on average).

A Nest Protect smoke detector sits inside of a large, enclosed plexiglass box. We use this custom-built test chamber to test how quickly smoke detectors will sound the alarm once different kinds of smoke are added to the environment.

Our smoke detection test chamber lets us test how quickly each model raises an alarm when smoke enters the environment.

Gianmarco Chumbe/CNET

Best smoke alarms compared

How I test smoke alarms and smoke detectors

When it comes to detecting smoke, time is of the essence. That is why we designed a test that simulates a real-life emergency. 

The first thing to know is that there are two main types of fires that these products are designed for: smoldering fires and flaming fires.

A smoldering (or slow-burning) fire refers to the combustion that occurs at the surface of a solid material. Smoldering fires produce large amounts of thick smoke but can't sustain a flame. Think of a cigarette slowly burning but never actually bursting into flames. 

CNET's smoke detector test chamber sits outside atop a cast-iron chimney, with flames flickering in the oven below.

Smoke detection testing in progress.

Gianmarco Chumbe/CNET

A smoldering fire can and will become a flaming fire if proper action is not taken immediately.

Flaming fires are the ones we're more familiar with, and they usually arise from the ignition of any flammable material, such as a flammable substance, wood, paper, etc. These generally produce less smoke than a smoldering fire but are more destructive.

In my backyard, I built a chamber that houses the smoke detector and fed to it the two different types of smoke through a chimney. I timed the quickness of the response. The faster the smoke detectors' alarm was triggered, the better.

To simulate smoke coming from a smoldering fire, I ignited 300g of charcoal and let it heat up for 10 minutes before feeding the smoke. I wanted to make sure most of the coals were ignited and that the smoke was thick enough to trigger the alarm. 

Recreating a flaming fire was easy, just 30g of shredded paper did the trick. Again, I ensured a significant amount of smoke was present before feeding it through the chimney and into the chamber. 

To the great discomfort of my neighbors, who had to endure smoke alarms going off randomly, and to whom I sincerely apologize, I repeated the whole process three times per smoke detector model under test and per type of smoke, totaling six test runs per smoke detector. Finally, I averaged the response times.

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Other smoke detectors we've tested

Kidde Firex Smoke Alarm i4618AC Ionization Sensor (Update: Out of Stock):As expected from an ionization detector, it had the best performance detecting a fast-flaming fire in just 16.9 seconds, and the second-best score detecting a slow-smoldering fire, in 28.1 seconds. As a former budget pick, we removed it form out best list because its been out of stock for some time.

Kidde Smoke Alarm 20SD10-V: Although we have not tested the Kidde Smoke Alarm 20SD10-V yet, we felt it was worth mentioning as an available product because it has a strong hardwired option. Some states and new construction require your smoke detector to be hardwired along with a battery backups. This smoke alarm by Kidde not only has a hard wiring option it stands out for its easy installation and reliable operation. The 10-year battery backup and associated warranty should be enough to meet any residential requirements. There's also an easy-access hush button in case the alarm does sound off unnecessarily. It also can connect with other compatible Kidde alarms for simultaneous alerts.

Kidde Firex PI2010 Hardwired Dual Sensor Smoke Detector (Update: Out of Stock): Lowest overall performance detecting a slow-smoldering fire, taking 83 seconds. Second-lowest performance detecting a fast-flaming fire, in 27.9 seconds. The device needs to be hardwired, but it comes with a 9-volt battery as backup. 

Onelink Battery Powered Smart Smoke and Carbon Monoxide Detector by First Alert (Update: Out of Stock): This model looked great at first: App-controlled, useful smart features and the ability to pair up with other smart home security devices make it a strong contender for the best for smart home. It did not impress us in the smoke detection test. It had the lowest performance detecting a fast-flaming fire and the second-lowest performance detecting a slow-smoldering fire, taking almost twice as long as the Nest. 

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Important factors when choosing a smoke detector

CNET's carbon monoxide tester in a glass box with a Nest detector.

A look at the interior of CNET's carbon monoxide detector.

CNET/Gianmarco Chumbe

Power source

Battery smoke detectors are incredibly easy to place, but there’s a problem: Local fire codes and state requirements often require hardwired smoke alarms in residential buildings, which can create insurance and remodeling headaches. I advise getting hardwired versions when possible to meet state requirements and use battery models for additional protection in other areas.

Battery backups

Battery backups are another common fire code requirement, so it’s a good idea to look at your local codes to see what kind of battery backup you need. You can check your national Fire Alarm and Signaling Code here.

Battery alerts

Many of my picks mute battery beeps and find other ways to let you know when backup batteries are running low. It’s a nice feature, especially when backed up by an app.

Sensor types

Different sensors specialize in different types of heat or particle detection. My top pick has a dual sensor to take advantage of both, as does Google's Spectrum sensor.

Smart home support

Support for Google Home, Alexa or other platforms may be very important for some users, and the added app support is great. This feature can be rare, but is useful for the right homeowners.

 

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Smoke detector FAQ

Are there different types of smoke detectors?

Commonly, smoke detectors utilize different smoke-detecting mechanisms, such as photoelectric sensors, ionization sensors or a combination of the two, called "dual sensors." We don't need to go too deeply into the science behind them, but it's helpful to know that the main difference between the two is their ability to detect different types of smoke. 

For instance, a smoke detector that has a photoelectric sensor is better at detecting slow-smoldering fires, while a smoke detector that has an ionization sensor will be better at detecting fast-flaming ones. Plenty of "combo" or "dual sensor" smoke detectors feature both mechanisms, so you don't have to worry about either eventuality.

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My smoke detector goes off, but there's no smoke?

Some smoke detectors, like dual-sensors, and especially ionization detectors, are designed to sense disruptions in the circuitry of the device. The ionization sensor is inside a chamber and has two electrically charged plates that ionize air between them. When smoke particles enter the chamber, they occupy the air within the plates, blocking the flow of ions and, consequently, triggering the alarm. Debris, dust, paint, cigarette smoke, dirt and steam particles can also have the same effect. Keep that in mind if you're renovating your home or if you have your smoke detector installed near a kitchen. If you suspect your smoke detector has been contaminated with foreign particles, give it a good cleaning.

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How do I clean a smoke detector?

Smoke detectors will have instructions on how to clean the device in the user's manual, but there are a couple of easy fixes you can try if you don't feel like looking for that elusive bit of paper. Grab a handheld vacuum or a vacuum that's equipped with the smallest nozzle piece. Then, simply vacuum every open spot you can find in your smoke detector. If you have an air blower, blow some air in those spots. If you're renovating your home, cover your smoke detector or remove it from the work area to prevent it from going off when no smoke is present.

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My smoke detector makes a chirping noise. What's causing it?

Most smoke detectors will produce a low chirping noise, signaling their batteries are getting low or that the unit itself needs replacing. This is a common feature of most smoke detectors but occurs mostly during the night when your home's temperature drops a couple of degrees. If the chirping continues during the day, it may be a sign of something else. Refer to your smoke detector's manual for troubleshooting specific to your smoke detector model. Keep in mind that the average lifespan of a smoke detector is 10 years, so if your detector is close to that, it'd be a good idea to play it safe and replace it.

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Our Experts

Headshot of Gianmarco Chumbe
Written by  Gianmarco Chumbe
Our expert, award-winning staff selects the products we cover and rigorously researches and tests our top picks. If you buy through our links, we may get a commission.
Headshot of Gianmarco Chumbe
Gianmarco Chumbe
Laboratory Technical Project Manager Gianmarco Chumbe has been part of the CNET Home team since 2018. He is in charge of developing and carrying out testing procedures for a wide variety of home appliances and smart devices including robot vacuums, smoke/CO detectors and air conditioning units. He takes a data-driven and creative approach to every project he is involved in, honoring his background in Science and Engineering.
Expertise SOP development and laboratory testing of home appliances and smart devices

What to consider

Power source

Battery backups

Battery alerts

Sensor types

Smart home support