'ZDNET Recommends': What exactly does it mean?
ZDNET's recommendations are based on many hours of testing, research, and comparison shopping. We gather data from the best available sources, including vendor and retailer listings as well as other relevant and independent reviews sites. And we pore over customer reviews to find out what matters to real people who already own and use the products and services we’re assessing.
When you click through from our site to a retailer and buy a product or service, we may earn affiliate commissions. This helps support our work, but does not affect what we cover or how, and it does not affect the price you pay. Neither ZDNET nor the author are compensated for these independent reviews. Indeed, we follow strict guidelines that ensure our editorial content is never influenced by advertisers.
ZDNET's editorial team writes on behalf of you, our reader. Our goal is to deliver the most accurate information and the most knowledgeable advice possible in order to help you make smarter buying decisions on tech gear and a wide array of products and services. Our editors thoroughly review and fact-check every article to ensure that our content meets the highest standards. If we have made an error or published misleading information, we will correct or clarify the article. If you see inaccuracies in our content, please report the mistake via this form.
Keep your home safe with a smoke detector -- the best ones start at $45
Smoke detectors are the kind of device that you never want to need but you always need it to work. All smoke detector units must be replaced every 10 years. So, if yours are coming up on a decade old or are already past their shelf life, then it's high time to get them replaced to ensure your and your family's safety.
Before choosing a smoke detector
If you've decided to replace your home's smoke detectors, it's important to determine what your state's laws about smoke and carbon monoxide (CO) detectors say. Ideally, all homes should have detectors for both, but this isn't yet mandated in all states across the US.
Also: The best fire extinguishers
You also want to consider what type of installation you have in your home. Simply removing the face of one of your units will reveal if they're wired or battery-powered. Keep in mind that wired smoke detectors also have batteries for backup power. So if yours are connected to wires in your wall, you know they're hardwired. If there are no wires connected to your home, then they're battery-powered.
- CO monitor
- No wiring needed
- Need to replace batteries periodically
- No voice alarm
Specs:
- Dimensions: 2" x 5" x 5"
- Power source: Battery powered
- Sensor type: Electrochemical, Photoelectric
- Alarm: Audible
- Battery type: AA replaceable batteries
This is the best option for a smoke and carbon monoxide detector because it's a seamless replacement to existing home smoke detectors. It's like taking your existing smoke detector and replacing for a brand new one plus a carbon monoxide alarm.
CO monitoring is extremely important, as it's commonly known as a silent killer: there are no smells or visible gases to alert you if you have high CO levels in your home. You can only tell what your home's carbon monoxide levels with a monitor.
The fact that this smoke detector is battery-powered makes for an easy installation. And the need for AA batteries means you won't have to buy specific batteries for this unit. However, do consider that you need to replace them promptly every six months for optimal performance.
And if you're all about safety, you can also get this bundle with a fire extinguisher.
- Voice and LED lights alarm
- Easy installation
- Ionization sensor only
Specs:
- Dimensions: 1.8" x 5.6" x 5.6"
- Power source: Battery powered
- Sensor type: Ionization
- Alarm: Audible, LED, and voice alarm
- Battery type: AA replaceable batteries
When looking to get the biggest bang for your buck, you definitely can't go wrong with this Kidde Safety combination smoke and carbon monoxide alarm. It's also a battery-powered option, so the two included AA batteries will require replacing every six months.
The voice alarm feature makes it stand out from others because it will say whether the alarm was triggered by fire, carbon monoxide, or a low battery, along with a regular alarm. And if you've ever had a dying battery make a smoke detector chirp in your home, then you're likely to appreciate the voice alert feature.
- Self-testing feature
- Night light
- Smart capabilities to connect to your mobile device
- Both battery or hardwired, depending on your current setup
- Expensive in comparison
- Not compatible with Alexa or Siri
Specs:
- Dimensions: 5.3" x 1.5" x 5.3"
- Power source: Battery powered or hardwired options
- Sensor type: Occupancy, humidity, split-spectrum, electrochemical
- Alarm: Audible, mobile, voice alerts
- Battery type: AA replaceable batteries
- Connectivity: 2.4GHz Wifi, Bluetooth Low Energy (BLE)
Google's Nest Protect is a smart smoke and CO detector that is leap and bounds above the competition. Its smart capabilities give you insights to your home's condition accessible right from your phone or tablet through the Google Home app.
Though it is pricier than other options, this device is the best option for a smart smoke detector and CO monitor. Several of them will cost a pretty penny in comparison to the average smoke detector, but, in the unfortunate even that one will be triggered, you'll get alerts of where the trigger was and if it detected smoke or CO.
The Nest Protect also does self-testing every month, which is something that each one of us should be doing already and most of us don't. This self-testing feature will give you the peace of mind that your device is working properly without having to remember to test it.
- No need to replace batteries
- Modern design makes it stand out
- Affordably priced
- No voice alerts
Specs:
- Dimensions: 2" x 5.7" x 5.7"
- Power source: Battery powered
- Sensor type: Electrochemical, Photoelectric
- Alarm: Audible
- Battery type: AA replaceable batteries
If you're in the market for battery-powered smoke detectors, then the X-Sense is a perfect pick. It comes with a sealed lithium battery that should last for ten years, which is right when you should replace your smoke detectors, independent of type. If you're the forgetful type (that's definitely me), then this is like a dream come true.
Combining both a smoke and CO detector, this device will alert with a chirp when it's coming to the end of its life, instead of waking you up at 3am every year with a chirp because you forgot to change the battery again.
- Easy install for wired replacement
- Ionization sensor for smoke
- No voice alert
Specs:
- Dimensions: 1.9" x 5.6" x 5.6"
- Power source: Hardwired
- Sensor type: Electrochemical, Ionization
- Alarm: Audible
- Battery type: 9 volt backup battery
Much like the First Alert Battery Powered sensor, this smoke detector is a great seamless replacement to most standard smoke detectors in homes today. This hardwired First Alert unit combines smoke detector and a CO monitor, with a battery backup.
If you take off your smoke detector cover to see that the unit is hardwired, then this First Alert will be easily installed with your home's existing wiring.
What is the best smoke detector?
The best smoke detector is the First Alert battery-operated smoke and carbon monoxide detector; it's a trustworthy, reliable replacement for existing smoke detectors.
You can see more of how these smoke and CO detectors stack up with each other here:
| Smoke Detectors | ZDNet's take | Sensor type | Alarm | Battery type | Battery-Powered | Hardwired |
| First Alert Battery Smoke & CO | Best overall | Electrochemical, photoelectric | Audible | AA replaceable | ✔ | - |
| Kidde Smoke & CO | Best for a budget | Ionization | Audible, LED, Voice | AA replaceable | ✔ | - |
| Nest Protect | Best smart option | Occupancy, humidity, split-spectrum, electrochemical | Audible, mobile, voice | AA replaceable | ✔ | ✔ |
| X-Sense 2-in-1 | Best battery-powered | Electrochemical, photoelectric | Audible | AA replaceable | ✔ | - |
| First Alert Hardwired Smoke & CO | Best hardwired | Electrochemical, ionization | Audible | 9-volt backup | - | ✔ |
Which is the right smoke detector for you?
Just because we chose what we consider to be the best smoke detector for a home, doesn't mean it's the best for your situation. If you prefer to get a smart unit that you can monitor from wherever you are, and get alerts right on your phone, even if you're away from home, then the Nest Protect is the best choice for you.
If you prefer a simple, affordable straight-down-the-middle option, then I'd recommend the Kidde Smoke & CO detector. Consider what your needs, budget, and safety concerns are when choosing something as important as a smoke detector.
| Choose this smoke detector... | If you... |
| First Alert Battery Smoke & CO | Want a plug-and-play replacement for your existing units |
| Kidde Smoke & CO | Prefer to stick to a budget but need both smoke and CO detectors |
| Nest Protect | Want to upgrade your setup to include smart home capabilities |
| X-Sense 2-in-1 | Want a battery-powered unit that is also inexpensive |
| First Alert Hardwired Smoke & CO | Prefer a hardwired unit to install with your home's existing wiring |
How did we choose these smoke detectors?
We combined experience, knowledge and research to determine which are the best smoke detector options on the market. Personally, I bought a 23-year-old home at the beginning of this year and it still had original smoke detectors. Needless to say, we upgraded these and added carbon monoxide monitoring as well. So I've had a bit of experience shopping and testing different brands and types of smoke detectors, which compels me to share, so others know not to make any mistakes we did.
What's the difference between smart smoke detectors and regular smoke detectors?
Bells and whistles aside, smart smoke and CO detectors perform the same core function as traditional alarms. They're not actually better or smarter at detecting threats. Smart smoke detectors have the benefit that they can be connected to wifi, so you can use capabilities like voice assistance, mobile alerts, and notifications when you're away from home.
The Nest Protect in particular, also has self-testing, which can eliminate a headache on its own.
What is ionization sensor?
Most alarms at homes right now use ionization sensors, particularly older smoke detectors. Ionization sensors detect flaming fires more easily than other smoldering fires. To detect more types of fires, it's best to have both photoelectric and ionization sensors combined, rather than just ionization.
What's the best smoke detector sensor?
Smoke detectors use different sensors to monitor for smoke. Photoelectric sensors use a light beam to easily detect smoldering fires, while ionization sensors can easily detect rapid flame fires via electrically charged particles. The best sensor is a combination of both to detect both smoldering and flaming fires.
Electrochemical sensors carbon monoxide.
Are there alternative smoke detectors worth considering?
There are many smoke detectors on the market, these are just a few of the best ones we gathered up. Here are some alternative pics to consider: