Simply put, a smoke detector can save your life.
We researched and tested some of the top smoke detectors available online, evaluating safety features, battery life, and ease of installation. Home inspector Dave Mitchell, who has seen many incorrectly installed detectors, recommends having a professional take care of even simple installs if you are unsure.
Our top pick, the First Alert Combination Smoke and Carbon Monoxide Alarm, detects smoke and carbon monoxide (CO), uses a voice alert system, and is easy to set up.
Here are the best smoke detectors.
First Alert SCO7CN Smoke and Carbon Monoxide Detector
Detects smoke and CO
Audio and visual alarms
Easy to install and change the batteries
Batteries need to be changed out periodically
The First Alert Smoke and Carbon Monoxide Detector can pick up trace amounts of smoke and carbon monoxide, and given its utility, it has a surprisingly low price point. If you are looking to upgrade or replace multiple detectors in your home, this is our top recommendation.
This dual-use detector features a voice alarm that tells you whether it detects smoke or carbon monoxide. This is important because it helps emergency responders know how to respond to the call and can also help you and your family egress safely. The detector is battery-powered, which makes it a breeze to install, although you will need to change out the batteries every six months. You can do this using the easy access point on the front.
In addition to having both audible and visual alarms, the test/silence button is also helpful and is clearly labeled on the front of the unit. If you experience a false alarm that you know you can silence, just press the button. Hold it down to test the alarm, which should be done at least once every time you switch out the batteries. You can also use this button to silence the annoying low-battery chirp alarm for up to eight hours. Just make sure to go back and actually switch out the batteries.
Price at time of publish: $73
Power Source: 2 AA batteries︱Sensor Type: Photoelectric︱Pack Size: 1
Kidde 10 Year Worry-Free Smoke Detector with Lithium Battery
10-year battery life
Easy to install
No low-battery chirps
May forget the expected replacement date
Does not detect carbon monoxide
For the most affordable alarm, the Kidde Worry-Free 10-Year Smoke Detector is the clear winner. It is a fraction of the cost of many other alarms but still offers 10 years of reliable performance. Powered by a 10-year lithium battery, this alarm brings all of the convenience of easy installation without adding the requirement to change the batteries every six months. You also don’t need to deal with low-battery chirps.
You will get an alert when the battery is near the end of its 10-year life, and the whole unit will need replacing. Depending on how well you monitor this, it may catch you off guard. Also, keep in mind that it does not detect carbon monoxide, but for the budget-friendly price, you can add a separate CO detection unit at the most appropriate place.
Price at time of publish: $23
Power Source: Lithium battery︱Sensor Type: Ionization︱Pack Size: 1
Best Smoke and Carbon Monoxide Detector
Kidde Battery-Operated Combination Smoke/Carbon Monoxide Alarm with Voice Warning
Smoke and CO detector
Easy to install
Batteries have to be changed out
Hush button might be hard to reach
This top-performing smoke detector includes a carbon monoxide alarm. It alerts you to the threat using a voice alert so that you can respond appropriately and notify emergency responders about the problem. The hush button allows you to silence false alarms, although you do need to be able to reach it to use it.
This is a battery-operated unit, which has pros and cons. It is easy to install—if you are replacing another Kidde alarm, you might even be able to use the same base and simply click the new unit on. However, as with all battery-powered units, it does mean that the batteries need to be changed every six months.
Price at time of publish: $45
Power Source: 2 AA batteries︱Sensor Type: Ionization, CO︱Pack Size: 1
Kidde FireX Hardwire Smoke and Carbon Monoxide Combination Detector 2 Pack
Detects smoke and carbon monoxide
Battery backup for power outages
Works with other Kidde bases
May need professional installation
Having a hardwired smoke detector helps it integrate with other sensors to create a comprehensive home safety system. The Kidde FireX hardwired detector can sniff out both smoke and carbon monoxide, adding to the protection power. It does have a 9V battery backup in case the power goes out, a necessary safety precaution. When one alarm in the system detects smoke or carbon monoxide, they all sound. This helps alert you to dangers even if you are in a different room or floor of your home. It uses a voice alarm to tell you if it detects smoke or CO.
Installation of hardwired detectors can be a bit more complicated, but Kidde systems use compatible bases. If you are replacing another Kidde product, you can likely use the same location to hardwire this detector and eliminate the need to touch up walls or paint. If you are installing a hardwired system for the first time, you will likely need to get the help of an electrician to run wires safely. This adds to the already high cost of these detectors. Buying in packs of two or more can save some money.
Price at time of publish: $50
Power Source: Hardwired with 9V battery backup︱Sensor Type: Photoelectric︱Pack Size: 1 or 2
Kidde Code One Smoke Detector
Easy battery change out
Only one battery needed
Comes with a battery
Does not detect CO
No voice alert
All you need to operate this convenient smoke detector is one 9V battery—rather than worrying about multiple batteries, just open the door to pop in one battery and attach it to the wall. This smoke detector is very simple, without any extra bells and whistles, such as voice alerts or CO detection. But it does a great job at its only job: detecting smoke and alerting you to get to safety.
Installation is very easy, especially if you are replacing another Kidde unit, and it comes with one 9V battery to get you started. You will need to change it out periodically—most emergency response units recommend every six months. There is a corresponding CO detector that uses a similar setup and also uses a 9V battery for power. Fortunately, this unit is so affordable that you can purchase both this detector and the Kidde Code One CO detector for less than a pricier combo unit.
Price at time of publish: $11
Power Source: 9V battery (included)︱Sensor Type: Ionization︱Pack Size: 1
Google Nest Protect 2nd Generation
Can test, silence, and check battery life from the app
Detects smoke and carbon monoxide
Calming voice alert
Available in battery-powered or hardwired
This smart alarm detects both smoke and carbon monoxide for thorough home protection. You can check on the status of the alarm and the battery life, silence false alarms, and even test the alarm from an app on your phone. The voice alert is friendlier than most, which can be pleasant but may not impart the same urgency as a loud beeping alarm. It does tell you whether it detects smoke or carbon monoxide, which is helpful to determine the right response.
The Google Nest Protect is an expensive alarm, which isn’t surprising given its interconnectivity and extra convenience features. You can monitor the alarm while away from home via the app. It includes a night-light that activates if you walk under the light at night. You can purchase it in packs of one or three, and it is available in battery-powered and hardwired options.
Price at time of publish: $119
Power Source: Battery-powered or hardwired︱Sensor Type: Photoelectric︱Pack Size: 1 or 3
Best Dual Sensor
FIRST ALERT BRK 9120LBL Hardwired Smoke Detector with Battery Backup
Two types of sensors
Hardwired to work with a system
Battery backup power
Does not detect CO
A bit pricey
Needs professional installation
Smoke alarms use either photoelectric sensors to detect fast-burning fires or ionization sensors to detect smoldering fires. While most prioritize one method over the other, the First Alert BRK 3120B detector uses both to provide comprehensive safety detection. It is hardwired but has a 9V battery backup to provide power if there is an outage. Unless you are already using a hardwired smoke detector in your home, you will likely need to get professional installation for this unit.
This detector is a bit more expensive than other smoke-only detectors. But given its reliable detection of every type of fire that could threaten you or your home, it is well worth the cost. However, it does not detect carbon monoxide, so you will need to purchase a separate detection unit if needed.
Price at time of publish: $58
Power Source: Hardwired, with 9V battery backup︱Sensor Type: Photoelectric, ionization︱Pack Size: 1 or 6
Best Voice Alarm
Kidde P4010ACSCO-WF Smoke and Carbon Monoxide Alarm with Smart Features
Alarm and voice alert
Alerts sent to your phone, family, and friends
Can control and check via smart home devices
Included battery backup
Requires professional installation
This smart detector uses a loud 85-decibel alarm and a voice alert that shouts “fire” or “carbon monoxide,” depending on what it detects. Better yet, the alarm goes to your phone via an app and the phones of other family and friends you’ve set up. It is also compatible with Google and Alexa and can alert you via those smart home devices as well. All of these alerts ensure that you will always know if you have a fire or CO in your home, even while you are away.
This is an expensive smoke detector but well worth it for its convenience and many alerts. It is more affordable than some other smart detectors, although it doesn’t come with as many testing and monitoring features. It is hardwired, which requires professional installation, but does have an installed 10-year lithium battery.
Price at time of publish: $80
Power Source: Hardwired with installed 10-year lithium battery backup︱Sensor Type: Photoelectric︱Pack Size: 1
Affordable and easy to install, our top pick is the First Alert SCO7CN Combination Smoke and Carbon Monoxide Alarm. It detects both smoke and carbon monoxide, alerting you using an audio voice alert and visual alarm. The Kidde Worry-Free 10-Year Smoke Detector is another great choice that offers worry-free performance at a fantastic price. It includes a lithium battery with a 10-year life, meaning no battery changes for you.
What to Look for in a Smoke Detector
Smoke detectors can be hardwired or battery-operated. Many hardwired smoke detectors have a battery backup to ensure that you will never lose power or the protection of your alarms. Batteries can be standard AA or 9V batteries. Some models also have lithium batteries that come installed in the unit itself and last for 10 years without needing to be changed. Most battery-operated models are easier to install but do require changing batteries periodically.
“You should always have a professional check the installation of a new unit or system,” says home inspector Dave Mitchell. In his role, he has seen many smoke detectors that were installed in the wrong place or not connected to a power source. Not only is this dangerous for you and your home, but it can also cause problems with your insurance company or home sale. “It can raise red flags for me as a home inspector,” says Mitchell. “It’s not worth risking your safety.”
Smoke detectors use one to two sensor mechanisms to monitor for smoke in the air: photoelectric or ionization. Both types of sensors detect any kind of smoke, but photoelectric sensors are faster at detecting smoldering, slow-burning fires than ionization sensors, which are better at detecting fast-burning fires. The most comprehensive smoke detectors have both sensors inside as well as additional safety monitoring, such as carbon monoxide detection.
Whether you have a hardwired or battery-operated model, you will eventually need to replace the unit itself. Most have a special alarm that sounds when the detector is at the end of its lifespan. Your user manual can tell you specific lifespan expectations, but most are between five and 10 years.
How do smoke detectors work?
Ionization smoke alarms have a small amount of radioactive material that ionizes the air around them, and they are generally more responsive to large flames. When smoke enters the chamber, it disrupts the flow of ions and activates the alarm. Photoelectric alarms, on the other hand, respond best to smoldering fires. This type of alarm works by using a light sensor. A light source is aimed into a sensor chamber, and if smoke enters it, light is reflected and triggers the alarm. You won't be able to predict what kind of fire you may have, so you should always have both types of protection in your home for ample safety.
How do you change a battery in a smoke detector?
To change your smoke alarm's battery, you'll need to remove the cover first. Most covers twist open, but for some, you'll have to use a screwdriver. Your user's manual should give you specific instructions based on your model, and most are easy to change once you've removed the cover. Simply disconnect the old battery (many use 9V or AA batteries, but some use lithium) and replace it with the new one. Make sure it's firmly in place and facing the correct way.
Use the test button after installing the new battery to ensure it's correctly installed. If the test alarm doesn't sound, your battery may be facing the wrong way. Mark the inside of the alarm with the date you changed the battery to remind yourself later on. You should also check your alarm's battery at least twice a year to ensure maximum safety around your home.
How many smoke detectors do I need?
According to the National Fire Protection Association, every level of your home should have a smoke alarm, including your basement. Smoke alarms are the fastest way to indicate fire and prevent it from further spreading to other rooms of the house, so you should have one in each bedroom and one outside every sleeping area. Even if your home already has a set number of hardwired alarms, you can still place extra ones that are battery-operated around the house as well. In the case of fire prevention, it's better to have an extra amount of alarms rather than not enough.
Why Trust The Spruce?
This article was researched and written by Katie Begley, a freelance writer specializing in home and family products. She has been writing for The Spruce since 2019. When researching top smoke detectors, Begley considered superior performance, multiple sensors, and installation. She also consulted with home inspector Dave Mitchell to see what he recommends for installation and required placement.