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To help you find the best smoke and carbon monoxide detector for your home, we researched all of the top models, researching for accurate detection capabilities, via high-quality sensors, long-lasting batteries and form factors that make the units easy to place just about anywhere in the house. Additionally, we were attracted to newer products with tech-forward features, such as integration with related apps and voice functionality that will let you know what is going on in your home. Today even the best smart light bulbs are packed with features. This is one of the best smart home devices that you can invest in.

The best product we researched was easily the Google Nest Protect Smoke + Carbon Monoxide Alarm (2nd Gen,) which is embedded with extremely accurate sensors, making it excel at its stated job duties, which go a step further by telling you approximately where in the home the breach is coming from. It transmits data via Bluetooth or Wi-Fi to a related app, which we found extremely responsive and easy to use, and the included batteries last five years. Keep reading to learn more about the Google Nest Protect Smoke + Carbon Monoxide Alarm and the other items on this list. You can also read about the best smart outlet to upgrade your home even further.

Top 6 Best Smoke and Carbon Monoxide Detector Compared

 #1  Google Nest Protect Smoke + Carbon Monoxide Alarm (2nd Gen) – Top Pick

WHY WE LIKE IT: Available in both wired and battery-powered models, with the latter boasting five years of battery life. Both models boast best-in-class sensors that can tell you where in the home any problems are coming from and these products integrate nicely with a fantastic app, easily making these our top pick.

  • Five year battery
  • Locates source of smoke or carbon monoxide
  • App is easy to use
  • Wired unit does not have battery backup
  • Extremely expensive
  • 2 year warranty ok, but lower than most on this list

The Google Nest Protect Smoke + Carbon Monoxide Alarm is designed from the ground up to keep you safe, with a suite of high powered sensors that not only let you know, within seconds, if you are experiencing a leak or fire, but where in the home the problem is coming from. The Nest Protect CO Alarm operates smoothly with a related smart home app, transmitting via Bluetooth or Wi-Fi, and is available in two separate models, one that is hardwired and one that is powered by batteries. The battery-powered model comes with six lithium batteries, which will get you five years of use right out of the box.

Though the sensors are rated to last for ten years, which is nice, the warranty is only for two years, which is okay, but lower than most other products on this list. Additionally, this is an extremely expensive product, which could be an issue if you have a large home you are looking to fill with multiple sensors. It’s a great addition to your other smart home and automation gear.

 #2  First Alert Hardwired Smoke and Carbon Monoxide Detector – Honorable Mention

WHY WE LIKE IT: Features extremely accurate photoelectric sensors, a wired form factor that contains a battery backup, for when the power goes out, and comes with a lengthy warranty of seven years. This is a great wired unit that doubles down on safety, thanks to the battery backup.

  • 7 year warranty
  • Battery backup
  • Connects to other alarms
  • Installation requires some work
  • Multi-connection setup can be confusing
  • Alarm noises not as loud as some other products on list

The First Alert Hardwired Smoke and Carbon Monoxide Detector is packed with a suite of photoelectric sensors as well as an electrochemical carbon monoxide sensor, which accurately detect trace amounts of both smoke and carbon monoxide and makes sure you stay safe from carbon monoxide poisoning. The unit can connect wirelessly with other alarms you’ve installed in your smart home system, so they’ll all go off at once in the case of a problem. The company also throws in a lengthy seven-year warranty, which is fantastic.

This unit is hardwired, so it requires a lengthier installation than a battery-powered unit. Additionally, setting up multiple products to interact with one another can be somewhat confusing, forcing you to get perilously close to the product as it emits test alarms. The best WiFi outdoor outlet can also help make your home smarter and safer.

Read also: Be sure to check out the best warm white led strip lights.

 #3  First Alert Battery-Operated Smoke and Carbon Monoxide Alarm – Easiest Battery Change

WHY WE LIKE IT: Filled with photoelectric sensors, which accurately detect smoke and CO, and uses a human voice to let you know where in the home the problem is. The battery changing procedure is extremely easy, and doesn’t require uninstallation, making this a fantastic product for those who want simplicity.

  • Voice location capabilities
  • Available in multipacks to save money
  • 7 year warranty
  • Should replace batteries twice a year
  • Goes through loud test alarms often
  • Installation can be tricky

The First Alert Battery-Operated Smoke and Carbon Monoxide Alarm is a fantastic product, which uses photoelectric sensors (as opposed to ionization-based) to accurately detect smoke and CO and further sensors help to locate the source of the problem. Changing the battery is extremely simple, and does not require the item to be uninstalled, and the company throws in a seven-year warranty, which is fantastic and in line with our number two pick.

This is a standard battery-powered product that uses AA batteries, which need to be replaced at least once a year, with many experts recommend them to be replaced twice a year. Additionally, it emits test alarms fairly regularly, which can be loud and off-putting.

 #4  Kidde Battery-Operated Smoke/Carbon Monoxide Alarm – Best Value

WHY WE LIKE IT: Boasts a great features to price ratio, with a voice alarm that lets you know exactly what the issue is, and a smartly designed battery latch that will not shut if the batteries have been installed incorrectly, further increasing the product’s safety rating. It also comes with a ten-year warranty, making this a product a fantastic value.

  • 10 year warranty
  • Alarm features human voice
  • Installation is easy
  • Ionization only
  • Should change batteries twice a year
  • Not compatible with Duracell batteries

The Kidde Battery-Operated Smoke/Carbon Monoxide Alarm comes with many of the same high-end features found in some of our top picks, while costing slightly less. This combo unit accurately detects both smoke and CO and the alarm features a human voice, which lets you know exactly what the problem is. We also liked the easy installation and the fact that the battery latch will not close if batteries have been put in improperly, taking away some of the guesswork. The 10 years of warranty is also tied for the longest on this list.

Though we found the sensors built-in with this product to be highly accurate, they are ionization-based, and not photoelectric, and experts say that the latter is slightly more accurate when it comes to smoke. Additionally, this is a traditional battery-powered unit and those batteries should be replaced around twice a year. As well as making your home safe, make it smarter with 6 of the best WiFi thermostats.

 #5  Kidde Hardwired Smoke and Carbon Monoxide Detector Alarm – Best Warranty (tie)

WHY WE LIKE IT: Hardwired product that contains battery backup, so you’ll be safe even when your home’s power goes out, with a 10-year warranty, which is tied with our number four pick for the longest. This is a great product with a great warranty.

  • Battery backup
  • Voice explains why alarm is going off
  • Up to 24 units can be linked together
  • Ionization only
  • Installation requires some light wiring
  • Test alarms can be loud

The Kidde Hardwired Smoke and Carbon Monoxide Detector Alarm comes with a lengthy ten-year warranty, which is tied for the longest available on this list. The product is hardwired but contains a battery backup, so you can be sure it’ll be receiving juice even if the power goes out in your home. The sensors are accurate and the alarm contains the use of a human voice, which lets you know exactly why the alarm is going off, which is useful. Additionally, up to 24 of these can link together, so when one alarm goes off somewhere in the house, they will all go off.

Though we found the sensors to be accurate in the detection of smoke and CO, this is an ionization-based product, and experts say photoelectric devices offer slightly better accuracy. Additionally, it requires some light wiring on the installation end, though nothing too unmanageable. You can also read about the best home security gear.

 #6  Vitowell Smoke and Carbon Monoxide Alarm – Best Budget

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WHY WE LIKE IT: Lowest priced item on the list, yet still packed with high-end features, such as photoelectric sensors, a light form factor (6 oz, lightest on list) and a five-year warranty. This is a great product for those looking for a budget combo detector.

  • Photoelectric sensors
  • Light form factor
  • 5 year warranty
  • No voice
  • Batteries should be replaced twice a year
  • Green light flashes every 30 seconds

The Vitowell Smoke and Carbon Monoxide Alarm is packed to the brim with photoelectric sensors, which experts say are better at detecting smoldering smoke than their ionization-based cousins, and boasts an extremely light form factor, at just six ounces. The company throws in a five-year warranty and the price is certainly right, as this is the lowest priced product on this list.

This item lets you know it is operating correctly by emitting a green light every 30 seconds, which is great for peace of mind but maybe not ideal for those who are sensitive to light as they try to sleep. Also, there is no voice component, so you won’t know exactly why the alarm is going off if it does go off. Also read about the best home security camera to keep your home safe.

Note: Other notable carbon monoxide alarms and detectors available that are worth mentioning here are the X-Sense Smoke & CO Detectors that features a photoelectric and electrochemical sensor and works as a smoke alarm in detecting carbon monoxide levels, and the Kidde Nighthawk AC Plug-in Operated Carbon Monoxide Alarm, a good CO detector with a bright digital display and does good to protect from CO poisoning.

See Also: You may also want to install the best LED strip lights in your home for better lighting.

How We Decided

To help you find the best smoke detector / carbon monoxide detector combo unit, we researched a multitude of products, researching for detection accuracy, with a mix of both ionization-based models and photoelectric models. We also populated the above list of the best carbon monoxide detectors with hardwired and battery-powered products, preferring hardwired models with battery backup, so as to increase peace of mind. After all, the best smart home devices should be simple and easy.

When something was battery-powered, we made sure you’d get a lot of use before having to replace the batteries. Most of the battery-powered products on this list can last nearly a year on one set of batteries, which is the industry standard, and our top pick can go five whole years before needing the batteries to be replaced.

We also favored products with some bells and whistles, like models that issue alerts via human voice, so you can know exactly what is going on, and those that feature advanced sensors that actually pinpoint where in the home any danger is coming from. Finally, we made sure each product boasted a long-lasting warranty of at least two years, with some ascending to seven and ten years. Speaking of smoke, the best air purifier for smoke will clean your air.

Smoke Detector / Carbon Monoxide Detector Buying Guide

The Most Important Features to Consider

  1. Sensors and Detection
    These products are packed with sensors to accurately detect if there is a fire or a carbon monoxide leak in your home. These sensors typically fall into two categories. Ionization-based sensors are better at detecting flaming fires, while photoelectric sensors are better at detecting smoldering flames. Each have their uses, though experts have concluded in recent years that photoelectric sensors are slightly more accurate. Carbon monoxide detectors are usually tested against a low CO level@@ 100 parts per million and a high CO level@ 400ppm.
  2. Power
    These products are typically powered via two methods, hardwiring and batteries. The former connects to your home’s electricity and occasionally include battery backups, in case your power goes out. Battery-based models can last around a year before failure, but experts suggest that the batteries be changed twice a year, as a safety precaution. Some units allow for easy battery replacement, so you don’t have to remove the product from your ceiling, or wherever it is resting.
  3. Additional Features
    Some newer models boast some additional functionalities, including interacting with a related app, as with our top pick. Others use advanced sensors to approximate where in your home the danger is coming from, which can help you get things sorted out. Some detectors eschew loud chirps for the human voice, which is useful because it can announce exactly what is going on, taking away some of the guesswork.

Smoke and Carbon Monoxide Detector FAQs

How often should these be replaced?

Results vary, though experts agree that these products should be replaced every five years. Occasionally, smoke detectors can go somewhat longer, with some companies suggesting a replacement every ten years.

What do you do if the carbon monoxide alarm goes off?

Carbon monoxide has no odor, unlike smoke, so when the alarm goes off you are going to want to take some precautionary measures. First, open any windows or doors, to help ventilate the space, turn off major appliances and then go outside. Afterwards, call a technician to come by to run more detailed tests.

Where should I place these?

While each product is different, most of these can be installed exactly where single use smoke detectors reside, on the ceiling. They all come with the necessary tools and components for installation.

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