Best Carbon Monoxide Detector Reviews

Best Carbon Monoxide Detector Reviews in 2019

Our favorite of the lot is the Nest Protect Smoke & Carbon Monoxide Alarm, which offers smart capabilities as well as being a combination alarm. It may not be everyone’s first choice, however, so read on if you think you’ll want something simpler. We’ve found five of the best readily available models, so let’s dive in and then we’ll discuss what you need in a detector for this silent killer.

Nest Protect Smoke and Carbon Monoxide Alarm
Best overall: Nest Protect Smoke & Carbon

You can also run multiples on the same setup if you’re willing to splurge on it, and Nest’s free app will let you know which room is going off. Overall, we’re super impressed with Nest’s dual-alarm. The only real issue is the price.

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Top 5 Carbon Monoxide Detectors

Name Power Source Rating
Nest Protect Smoke & Carbon Battery Powered 5/5 Check Price
CO Inspector Industrial by Sensorcon Battery Powered 4.5/5 Check Price
First Alert CO605 Plug-in with Battery Backup 3.5/5 Check Price
Kidde KN-COPP-3 Nighthawk Plug-in with Battery Backup 4/5 Check Price
First Alert SC7010BV Plug-in with Battery Backup 4.5/5 Check Price

1. Best Overall

Nest Protect Smoke and Carbon Monoxide Alarm

Nest Protect Smoke & Carbon Monoxide Alarm

Product Rating 5 /5
Reviewed by:

The Nest Protect Smoke & Carbon Monoxide alarm is our favorite of those we took a close look at. This battery powered smart combination alarm makes a comprehensive solution for your home’s safety.

It’s also able to interface with the rest of Nest’s devices, meaning it’s a good way to get started on making sure that your home’s security system is consolidated in a single app on your phone.

It’s powered by 6 AA batteries. Just because it’s smart, however, doesn’t mean it’s lacking in the basics. It still has a loud alarm which will alert you in the event of rising carbon monoxide levels. The entire alarm is rated for ten years as well, so you won’t have to replace it anytime soon.

Pros and Cons
  • Ten year lifespan
  • Smart capabilities
  • Battery operated
  • Multiple devices can be used with the app
  • Rather expensive
  • A bit difficult to install

2. Best Portable Carbon Monoxide Detector

Sensorcon Tough, Waterproof, USA Made

CO Inspector Industrial by Sensorcon

Product Rating 4.5 /5
Reviewed by:

If you’re concerned about being able to track down the source of the CO entering your home and don’t want to invest in a ton of different sensors for each individual room, then the CO Inspector Industrial makes a great, if pricey, solution.

This is a highly portable carbon monoxide detector, used primarily in industrial environments to seek out the causes of environmental hazards.

For a homeowner it might be a bit overkill, but if you’ve been having repeated problems with other alarms going off and can’t pinpoint the source then you’ll find it quite handy. After all, carbon monoxide poisoning is serious business and being able to find the source is always welcome.

It’s not really wall-mountable, although the clip could be used in areas where you think the gas may build up pretty easily. If you want a portable carbon monoxide sensor then pick this one up. It’s up to par for any environment where the dangerous gas may be present.

Pros and Cons
  • Super accurate up to 200ppm
  • Highly portable to pinpoint problems
  • Durable construction
  • Free recalibration offered by Sensorcon
  • Expensive
  • Not a wall mounted unit

3. Best Budget Carbon Monoxide Detector

First Alert CO605 Carbon Monoxide

First Alert CO605 Carbon Monoxide Plug

Product Rating 3.5 /5
Reviewed by:

Not everyone has a ton of money to invest in their carbon monoxide detector and that makes something cheap but functional a great idea. It’s especially useful for those on a tight budget who want to make sure that they’ve got their bases covered with multiple alarms.

This is a plug-in unit with a battery backup, so you’ll never have to worry about it shutting off. Instead you’ll be able to make sure your family is safe even when the power is out.

It’s super simple to install and operate as long as you have a bit of electrical knowledge. Just tie it in to the power source and you’ll be good to go. It comes complete with a test mode so you can ensure it’s still working as well.

Overall, this may be one of the best solutions for those who are on a tight budget and wanting to make sure they have multiple alarms. It’s a bit cheap in construction, but it works and that’s the important part.

Pros and Cons
  • Dual power source with plug in and battery
  • Super cheap price per unit
  • Alerts when battery is low
  • Extremely easy to use
  • Low build-quality
  • Have to push a button to see the CO levels when beneath the alarm threshold

4. Best Non-Smart Carbon Monoxide Detector

Kidde KN-COPP-3 Nighthawk

Kidde KN-COPP-3 Nighthawk

Product Rating 4 /5
Reviewed by:

If you’re not looking for a smart option, then we feel that the Kidde KN-COPP-3 is probably your best bet. This plugin detector with battery backup is all-around cool and you’ll quickly find it to be a welcome addition to your home.

The biggest advantage is that it has a big LCD panel which takes a reading every fifteen seconds and displays it right there at all times. On top of that its low-profile design allows it to be easily mounted in whichever room you desire.

There’s a five-year limited warranty included with your detector as well.

If you’re not willing to shell out for a smart option, then this great detector from Kidde is the best bet. The constant display works wonders for the paranoid and its low-profile keeps it from standing out too much.

Pros and Cons
  • Constant readings displayed
  • Loud alarm when levels rise too much
  • Five year warranty
  • Low-profile design for easy placement
  • Dangling cord can be a pain
  • Not a ten year design

5. Best Combination Alarm

First Alert SC7010BV

First Alert SC7010BV Hardwired

Product Rating 5 /5
Reviewed by:

We really have a thing for combination alarms and the hard-tested SC7010BV is one of our favorites. This plug-in with battery back up combination alarm is affordable and can make a solution for a whole room with quite a bit of ease.

The only thing that we don’t like is the lack of an LCD readout to give you levels, but apart from that it’ll fit into most mountings for fire alarms and makes the whole process quite a bit easier than you’d think.

It also has a voice warning system which will let you know which of the alarms is going off just in case anything happens.

For the price and utility, we strongly favor this combination alarm. It works great, has a long life, and really can’t be beat unless you’re going with a smart alarm.

Pros and Cons
  • Combination alarm for smoke and CO
  • Mounts in standard fire alarm fixtures
  • 10 year warranty
  • Voice to differentiate alarm types
  • No readout for CO levels
  • Doesn’t last as long as the package says

Carbon Monoxide Poisoning and You

Nearly everyone has their home protected by a fire alarm. Indeed, it’s even required in most areas that you have at least one present in the home. But do you have a carbon monoxide detector? Carbon monoxide is an odorless, deadly gas which can cause acute or chronic poisoning in the people who are exposed to it.

That means it’s nearly impossible to detect without a device designed to do so. It can be problematic to trust just anything this important to chance. That means it’s important for your safety to make sure that you’ve got the best carbon monoxide detector available.

Since this gas can build up in your home, it’s important to know the hows and whys behind it’s build-up and the possible symptoms you can experience when exposed to it.

Thankfully, there is a lot of information out there to help you make sure that you don’t end up in trouble and if you pair it with the right equipment it’s an entirely avoidable problem.

Carbon Monoxide

Carbon monoxide, or CO, is usually a product of incomplete combustion.

When something burns, one of the primary outputs is thermal energy(ie: fire) and carbon dioxide which comes from the oxidation of the carbon contained within the combustible material.

It’s a pretty simple molecule overall, but it can build up in the blood which makes it extremely dangerous since the body handles it differently than CO2.

As a general rule, CO is slightly denser than the surrounding air. This means it tends to disperse fairly evenly through a room, although the usual sources of the gas means it will often rise initially.

Depending on the layout of your home, this means that it’s most likely to build up in basements.

Sadly, there are some definite disadvantages to modern, energy efficient homes. One of the largest disadvantages of these designs is the fact that they minimize the interfacing between indoor and outdoor atmospheres which can cause pollutants to build up indoors.

Common Sources in the Home

Carbon Monoxide Poisoning and You

The most common source of carbon monoxide within a home is gas-fired appliances. Any sort of fuel which is burning indoors can cause the gas to increase its atmospheric share indoors since combustion is rarely complete.

A misfiring furnace, water heater, or other device can cause a rapid build up of CO within the home and it can turn deadly faster than you’d think. This means it’s important to keep an eye on any appliance which uses natural gas or has fire. A significant malfunction can boost things to obscene levels rather quickly.

Try not to use any kind of generator or fuel-powered tool within your home. There may be instances where this is unavoidable, but if that occurs then you need to make sure things are well vented in order to avoid any danger.

Other sources are pretty varied, and primarily occur accidentally or during misuse of an appliance, but some of the various things which have killed or harmed people over the years include:

  • Idling a vehicle in a closed garage for an extended period.
  • Use of barbecue pits indoors for heat in emergencies, or in an enclosed garage space for whatever reason.
  • Using a portable generator indoors.
  • Using ovens for warmth while open as a back-up heater

Common sense can usually protect you, but the chance of a misfiring appliance occurring at least once in your lifetime is pretty high so it’s better to make sure you’re prepared.

Symptoms of Carbon Monoxide Poisoning

Even with the best alarm, mistakes can happen.

The first thing to manifest in non-fatal carbon monoxide poisoning is generally flu-like symptoms which clear up when you go outside.

If you feel the sudden onset of this then it’s best to get outside. Leave the door open behind you, but it’s time to call in a professional if this happens.

Acute poisoning from carbon monoxide can require medical treatment even if your symptoms have you “in the clear” by just going outside. This is because of delayed neurological effects which can occur.

These are pretty severe, including full-blown delirium, psychosis, sudden bouts of depression despite the lack of previous instances and more. These effects can occur 2-40 days after the initial poisoning incident.

The first symptom is a constant headache. At 35ppm this headache will begin to occur after six to eight hours of exposure. It’s actually recommended to never expose yourself to 25ppm or over for more than an hour by the CDC, so this is already a dangerous level.

At higher levels even a couple of breaths can be fatal, at a level of 12,000+ppm it’s been found that people fall unconscious within a couple of breaths.

Most cases of CO poisoning are acute, but long term exposure to levels over 5ppm can also cause some pretty serious problems. These include increased risk of cardiovascular problems, depression, and a whole host of symptoms.

The basic idea is that you want to minimize your exposure to this gas at all costs.

Picking Your Carbon Monoxide Detector

Fortunately, there’s one way to make sure that you’ve got a great carbon monoxide detector in your home: only purchase detectors which are signed off on by the Underwriter’s Laboratories(UL).

Other than that, however, there’s a few different things you may wish to keep in mind when it comes time to select your CO detector.


The battery life of your carbon monoxide detector can be a bit of a concern. At the very least you should be testing your device at least once every couple of months, if not every month. Unlike a fire detector, there’s no real way to just test one out so you’ll usually have a test button.

There are several models which are plug-in. We don’t recommend using a completely hard-wired CO detector, as often the actions which will cause rising levels occur when there’s a power outage.

On the other hand, hard-wired models with a battery back-up can be quite useful. They’re probably our favorites of the bunch, but when it comes down to it the main takeaway is to not go with a model which is only powered by a plug.

Also, remember to replace the batteries every six months if your model has them, even if it doesn’t seem like you need to. Remember that carbon monoxide is virtually undetectable.

Voice Alarms

Many carbon monoxide detectors have an additional feature: they have a voice alarm in addition to the standard beeping. Quite often these come in combination with a fire alarm.

These are great for most homeowners, allowing you the additional warning instead of you wasting valuable time searching for the source of the beeping.

Digital Display

Having an LCD display which allows you to view the parts per million is super important. This lets you know what kind of levels you’re experiencing on a day to day basis.

While ideally there should be no carbon monoxide contained within your home, realistically you’re probably looking at levels of 0.5-5ppm depending on the appliances running in your home and how air-tight things are.

You also want some backlighting to go with it, especially if the model you’re looking at is a plug-in with a battery back-up.

We especially recommend getting an LCD display for those with energy efficient homes. Their nature means that air has a tendency to stay inside and be recirculated which can lead to higher carbon monoxide levels if something is going wrong.

Built-in Memory

Built-in memory is important for more than one reason.

The biggest reason is a bit morbid, but it may come in handy: it’ll let doctors or emergency personnel know what kind of levels they’re dealing with in the event of an acute case of carbon monoxide poisoning.

It can also let you figure out what risk factors are in your house when it comes down to it, since you’ll know when levels peak and fall.

Combo Options

CO detectors are often combined with smoke alarms. This allows you to make sure that you have both of these vital realms covered.

Since some municipalities can require quite a few alarms, you may want to consider going down this route in order to make sure that each room is fully covered with a single device.

The only real problem is the fact that many combo alarms that are affordable are going to lack LCD displays This is an issue if you’re concerned about monitoring levels.

Placing Your Carbon Monoxide Detector

Knowing how to place your CO detector is just as important as making sure that you’ve got them initially.

Ideal Placement for Your Detector

Like we discussed earlier carbon monoxide has a tendency to disperse evenly through air but the initial sources are almost always heated.

This means that convective action will cause the gas’ tendency to rise when initially released.

Obviously, you’re going to want to place them higher up on the wall. It’s a fairly common myth that recommends they be placed low on your wall due to the density, but the difference is so minute that it’ll disperse once the convective action has been settled.

You’ll also want to place them away from any kind of heater or gas-fired appliance. This actually includes devices like space heaters, since they can also cause partial oxidation of carbon molecules in the air.

Vents, registers, and other sources of air flow which are attached to your furnace should be avoided as well.

You also want to avoid very humid areas, since it can affect the accuracy and lifespan of the detector.


  • Carbon monoxide detectors function best when they’re placed about five feet off the ground. This makes LCDs easy to read as well as allowing them to read the air at the “average” level.
  • Place them at least five feet away from ovens, stoves, furnances, and other devices which will cause some level of increased CO in the air upon starting. If you don’t, you could find yourself having to respond to a ton of false alarms.
  • Keep them away from registers, vents, and ducting in order to make sure that you don’t get false-positives… or false negatives, depending on the source of carbon monoxide within your home.
  • Avoid placing them in or near humid rooms such as bathrooms to prolong their lifespan and ensure that you continue to get accurate readings.

How Many to Place

In an ideal home setup, you’ll want to place a carbon monoxide detector in the common areas of each floor and in each room where someone will be sleeping.

This is pretty much the safest way to utilize them, and if you go for a combo option then you’ll also have your fire detector needs covered at the same time.

This is what we recommend for most people, but if budget dictates a lesser amount then you should at least have one in a central area of your home.


Carbon monoxide detectors are one of the essential safety features available in the modern home. Hopefully you’ll never have to test yours, but in the event you do need one they’re a lifesaving and invaluable device.

We recommend making your choice carefully in order to ensure you get the best carbon monoxide detector for your needs, rather than just a random one that you hope works. Stay safe out there!


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Max Perzon

About Max Perzon

Max is a 28 year old blogger from Sweden that loves to review home related products, and now writes for Homethods full-time. Read more about him