10 of The Best Carbon Monoxide Detectors

By Jason Horton

Here's a list of what I consider to be the best CO detectors for use in residential settings. The best detectors generally cost over $25 each so if you're looking for cheaper alternatives then see these low cost options.

Things to Consider When Buying Carbon Monoxide Detectors

  • Your Budget:
    When you consider that you may need 4 detectors or more to cover all areas of your home, the price starts to add up - so make sure you leave enough room in your budget for all the detectors you need..

  • Sensor Life:
    The sensors in a detector have a limited life span and the entire unit has to be replaced once the time limit is reached - this typically ranges between 5 and 10 years.

  • Sensitivity:
    CO concentration levels are measured in Parts Per Million (ppm) with standard detectors measuring levels from 30-40 ppm and sounding the alarm with consistent levels over 70 ppm which is fine for most people. If you have special health concerns such as respiratory illness, advanced age, or pregnancy, then you might want to consider one which measures levels as low as 10 ppm.

  • Digital Display:
    This is an important feature which some of the cheaper models don't have. These allow you to look through the history of CO levels since the last time you reset the detector - this is extremely useful for seeing if you have low levels of CO that don't trigger an immediate alarm but which might be harmful if exposure continues long term.

  • Power Source:
    You have four main options:

    • Battery operated
    • Plug into a wall socket
    • Hard-wired into your home's electricity supply (this option usually requires a contractor to install)
    • Combination of plug in and battery backup

    A power blackout is a time of heightened risk of CO exposure because that's when many people are most likely to be using fossil fueled appliances such as heaters and power generators, so I personally advise only to get a detector which uses batteries and will continue working when the power goes out. For this reason I have not included any of the hard-wired models below.

  • Manufacturer:
    Over the last year or so there have been a number of new low cost 'brands' appear on the market. Typically it's very hard to find out who the actual manufacturer is, which in turn makes it quite difficult to verify their claims or warranties - many of them have also not been certified by UL (Underwriters Laboratories). For these reasons you won't find me recommending 'brands' like X-Sense, Gotideal, or Yondwin.

 

The Best Carbon Monoxide Detectors

These are listed in two categories:

Please note that the prices listed below are subject to fluctuations so I've listed the price that each unit typically sells for.

 

Stand-alone Carbon Monoxide Detectors

This is the option that most people go for because many offer the additional feature of a digital readout, or because they already have smoke detectors installed.

Kidde C3010D

Kidde C3010D
Manufacturer: Kidde | Price: Usually under $50

Power: Sealed in lithium battery which activates when mounted - the battery can be deactivated if needed.
Sensor Life: 10 years
Digital Display: Yes
Sensitivity: The digital display will show levels down to 30ppm. The alarm will sound at:
  • 70 ppm detected over 60 to 240 minutes
  • 150 ppm detected over 10 to 50 minutes
  • 400 ppm detected over 4 to 15 minutes

Kidde did a brilliant job with the C3010D and in my opinion it is the top CO detector currently available, beating out the competition with its excellent combination of features and value. One of its biggest selling points is that it comes with a sealed battery which lasts for 10 years, as does its electrochemical sensor. It has a digital readout which shows the current CO levels (updated every 15 seconds) or you can use it to see what the peak levels were since it was last reset. Although its up-front cost is a bit higher than many other detectors, the total cost of ownership is lower because of its long life backed by the manufacturer's 10 year warranty and the fact that you don't have to buy 10 years worth of replacement batteries. If you'd like to know more then please read this detailed Kidde C3010D review.
Get the latest Kidde C3010D price & customer reviews at Amazon.com.

Kidde KN-COPP-3

Kidde KN-COPP-3
Manufacturer: Kidde | Price: Usually under $30

Power: Plug in with 9v battery backup.
Sensor Life: 10 years
Digital Display: Yes
Sensitivity: The digital display will show levels down to 30ppm. The alarm will sound at:
  • 70 ppm detected over 60 to 240 minutes
  • 150 ppm detected over 10 to 50 minutes
  • 400 ppm detected over 4 to 15 minutes

The KN-COPP-3 Nighthawk is Kidde's top selling CO alarm and it can usually be found at the top of Amazon's best seller list. It has very similar specifications to the C3010D listed above with the primary difference being that it plugs directly into a wall socket and uses a 9v battery as a backup power supply - it alerts you when the battery needs replacing. It also has a 6ft extension cord so you don't have to mount it exactly where the wall socket is. You can find out more by reading this extended KN-COPP-3 review.
Get the latest KN-COPP-3 Nighthawk price & customer reviews at Amazon.com.

First Alert CO615B

First Alert CO615b
Manufacturer: BRK | Price: Usually under $30

Power: Plug in with 2 AA batteries for backup.
Sensor Life: 7 years
Digital Display: Yes
Sensitivity: The digital display will show levels down to 30ppm. The alarm will sound at:
  • 70 ppm detected over 60 to 240 minutes
  • 150 ppm detected over 10 to 15 minutes
  • 400 ppm detected over 4 to 15 minutes

First Alert, by BRK Electronics, is one of the two biggest brands in CO detectors (Kidde is the other). The back-lit digital display on the CO615B shows the battery level, CO concentration in ppm, and historical peak levels since the last reset. The CO615B customer reviews and forum posts around the web are generally very positive and it has a 4.5 star rating on Amazon. The only reason it's not further up this list is because it only has a 7 year life compared to the 10 year life of the Kidde options above. It also comes with a 6 foot cable and 2 AA batteries. If you'd like to read more then take a look at this First Alert CO615 Review. By the way, Amazon incorrectly has the CO615B listed as the CO615 which is the version without battery backup - the following link will take you to the correct version with battery backup:
Get the latest First Alert CO615B price & customer reviews at Amazon.com.

Universal MCND401B

Universal Security Instruments MCND401B
Manufacturer: Universal Security Instruments | Price: Usually under $30

Power: Plug in with 9v battery backup.
Sensor Life: 5 years
Digital Display: Yes
Sensitivity: The digital display will show levels down to 30ppm. The alarm will sound at:
  • 70 ppm detected over 60 to 240 minutes
  • 150 ppm detected over 10 to 15 minutes
  • 400 ppm detected over 4 to 15 minutes

Universal Security Instruments is a U.S. based company founded in 1969 to produce home safety products and they specialize in fire and CO detection. The MCND401B is different to the other alarms I've recommended above because in addition to detecting CO it also alerts you to dangerous Natural Gas / Methane build ups which can occur when gas stoves or heaters fail. Like all the other detectors I've listed here this one has UL certification but in addition it is also California State Fire Marshal and Federal Housing Authority (FHA) approved. The digital display shows current CO levels and historical peaks in ppm and it also shows GAS and sounds the alarm when elevated natural gas levels are detected.
Get the latest MCND401B price & customer reviews at Amazon.com.

Kidde KN-COU-B Ultra Sensitive

Kidde KN-COU-B
Manufacturer: Kidde | Price: Usually about $150

Power: 3 AA Batteries.
Sensor Life: 10 years
Digital Display: Yes
Sensitivity: The digital display will show levels down to 10 ppm. The alarm will sound at:
  • 20 ppm detected for more than 115 minutes
  • 70 ppm detected over 20 to 60 minutes
  • 150 ppm detected over 7.5 to 21 minutes
  • 400 ppm detected over 3 to 8 minutes

The Kidde Ultra-Sensitive Battery Powered Carbon Monoxide Monitor KN-COU-B costs a lot more than typical options because it is capable of measuring much lower concentrations of CO than most residential detectors. Typical households will not need this level of sensitivity - you only need to get one of these if you have a medical condition that makes you more susceptible to low concentrations of CO gas. The alarm will initially sound every 10 seconds at the concentrations and durations listed above, however if the elevated CO levels continue for longer than the time ranges above then the alarm will begin sounding every 5 seconds. Because it alerts you to very low ppm levels it also comes with a 'hush' function which lets you turn the low level alerts off when not needed.
Get the latest Kidde KN-COU-B price & customer reviews at Amazon.com.

 

The Best Smoke and Carbon Monoxide Detectors

If you don't need a digital readout then buying combination detectors can save you a few dollars compared to buying both types of detectors separately. The reason these don't have digital readouts is because they need to be mounted on or close to the ceiling to do their smoke detection work effectively.

First Alert SCO500B Wireless with Voice

First Alert SCO500B

Manufacturer: BRK | Price: Usually about $50

Power: 2 AA batteries.
Sensor Life: 7 years
Digital Display: No
Sensitivity: The alarm will sound when:
  • 70 ppm CO detected over 60 to 240 minutes
  • 150 ppm CO detected over 10 to 15 minutes
  • 400 ppm CO detected over 4 to 15 minutes
  • Anytime smoke is detected by this unit or any others it has a wireless connection with

The SCO500B tells you what the problem is when the alarm sounds so that you know if the danger is CO or smoke - here's a sample of its alarm sounds:

Here's a sample of what it says when you first turn it on:

The SCO500B also uses a wireless mesh network to communicate between sensor units - if a threat is discovered in one part of your home then all the units you have can sound the alarm regardless of which room they're in. Each unit can be programmed with its location - you can have up to 11 locations within your network. The mesh network provides secure wireless communication between alarms using 915 MHz frequency with 65,000 security codes and 3 channel frequency hopping.
Get the latest First Alert SCO500B price & customer reviews at Amazon.com.

Kidde P3010K CO

Kidde P3010K CO

Manufacturer: Kidde | Price: About $40

Power: Sealed in lithium battery which activates when mounted - the battery can be deactivated if needed.
Sensor Life: 10 years
Digital Display: No
Sensitivity: The alarm will sound when:
  • 70 ppm CO detected over 60 to 240 minutes
  • 150 ppm CO detected over 10 to 15 minutes
  • 400 ppm CO detected over 4 to 15 minutes
  • Smoke is detected

The P3010K CO is part of Kidde's range of smoke alarms individualized for each type of room - this one is labeled "K" for kitchen because the other smoke alarms in this series don't have CO sensors, however it can be used as a combination smoke and CO alarm in any part of the home. It has the same CO sensor and 10 year sealed battery as the C3010D above. It also meets the following standards: The State of California Fire Marshall, NFPA 101, Federal Housing Authority (FHA), and Housing and Urban Development (HUD). For further reading see this: Kidde P3010K CO Review.
Get the latest P3010K-CO price & customer reviews at Amazon.com.

Nest Protect

Nest Protect

Manufacturer: Nest | Price: Usually under $150

Power: 6 Lithium Metal batteries (included).
Sensor Life: 10 years
Digital Display: No, provides information via Smart Phone or Tablet
Sensitivity: The alarm will sound when:
  • 70 ppm CO detected over 60 to 240 minutes
  • 150 ppm CO detected over 10 to 15 minutes
  • 400 ppm CO detected over 4 to 15 minutes
  • Either smoke or fire is detected

Although the Next Protect costs twice as much as many of the alarms it competes with, it is still an Amazon top seller because it has a few features that the others don't have including:

  • If you have a Nest Thermostat then Nest Protect can shutdown appliances such as your furnace or air conditioning systems in an emergency.
  • It sends progress alerts to your phone or tablet letting you know if smoke and/or CO readings have fallen to safe levels.
  • You can set it to detect movement at night and turn on a night light.
  • You can view historical information via its App.

It also speaks and can tell you the nature of the alarm and where the problem is located - here's an example:

Nest go out of their way to make their products stand out from the rest, both in terms of features and aesthetics. You can read more in this Nest Protect review.
Get the latest Nest Protect price & customer reviews at Amazon.com.

Kidde KN-COSM-BA with Voice Alarm

Kidde KN-COSM-BA combined Smoke & CO Alarm
Manufacturer: Kidde | Price: Usually under $35

Power: 2 AA Batteries.
Sensor Life: 5 years
Digital Display: No
Sensitivity: The alarm will sound when:
  • 70 ppm CO detected over 60 to 240 minutes
  • 150 ppm CO detected over 10 to 15 minutes
  • 400 ppm CO detected over 4 to 15 minutes
  • Smoke is detected

The Kidde KN-COSM-BA is another Amazon top seller and it speaks to tell you if the problem is fire or CO, and it tells you when the batteries need replacing. It will also tell you if it has sensed a peak CO level of more than 100 ppm when you press the 'test' button. It uses both ionization and photoelectric smoke sensors enabling it to detect both slow burning and rapid burning fires quickly. The KN-COSM-BA doesn't connect to other detectors so if you want that feature then you'll have to spend a few more dollars and chose either the First Alert SCO500B or Nest Protect listed above.
Get the latest Kidde KN-COSM-BA price & customer reviews at Amazon.com.

 

Honorable Mention

This one doesn't fit neatly into the categories above so I've placed it here.

MDS300-401CN Combined CO, Natural Gas, Smoke and Fire Alarm

MDS300-401CN combined CO, natural gas, smoke and fire alarm
Manufacturer: Universal Security Instruments | Price: Usually about $60

Power: A separate 9v battery is needed for each detector.
Sensor Life: 5 years for the CO detector and 10 years for the smoke alarm
Digital Display: No
Sensitivity: The CO alarm will sound at:
  • 70 ppm detected over 60 to 240 minutes
  • 150 ppm detected over 10 to 15 minutes
  • 400 ppm detected over 4 to 15 minutes

This is a 4 in 1 pack for detecting carbon monoxide, natural gas, smoke and fire. It's different to the other combination alarms mentioned above in that it actually comes in two separate units; a smoke and fire alarm which you mount on the ceiling, and a combination carbon monoxide and natural gas alarm with a digital readout which you mount on the wall. The digital readout provides current levels of gas detection as well as historical peak levels. The CO & natural gas detector is a plug-in unit which uses a 9v battery for backup when the power fails. The manufacturer provides a 10 year warranty on the smoke & fire alarm, and a 5 year warranty on the CO & natural gas detector.
Get the latest MDS300-401CN price & customer reviews at Amazon.com or purchase the CO & Gas detector separately.

 

Compatibility with Home Security Systems

There are also carbon monoxide detectors which are designed to work with home security systems. Some of these detectors will only work with specific brands of security systems. Some have 'open protocols' so that theoretically they could work with any compatible standard, however many of these have only been certified by UL when used with the same brand of security system. For these reasons I have not listed any of these types of detectors here - if you have a home security system and you'd like your CO detectors to work with it, then contact the manufacturer to find out which detectors are compatible.