Last updated: August 10, 2021

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Carbon monoxide is a poisonous gas that can be life-threatening to humans. The gas can be produced by fireplaces and heaters. The gas is also dangerous because it is odourless, tasteless and colourless, and can only be detected with the help of a CO detector. These can save lives in an emergency.

In our comprehensive CO detector test 2021 we want to help you find the best CO detector. We present many different models for this purpose. These include standard CO detectors, but also mobile detectors and networked detectors are compared in our test. In addition, we inform you about the advantages and disadvantages of the models, which should help you with your purchase decision.




The most important facts

  • Carbon monoxide is a poisonous gas that is difficult to notice because it is odourless, tasteless and colourless. It is produced by incomplete combustion of substances containing carbon. A CO detector is needed so that the gas can be detected at all. It sounds an alarm as soon as a certain value is measured.
  • An alarm must be taken seriously, as carbon monoxide poisoning can lead to death
  • CO detectors can only detect an increased level of carbon monoxide and therefore do not replace smoke detectors

The Best Carbon Monoxide Detector: Our Picks

Buying criteria for carbon monoxide detectors

In the following section, we will show you which aspects and criteria to look out for when deciding on a CO detector.

The criteria for deciding on the right CO detector are:

We go into more detail about the criteria in the following paragraphs.

Product size

The size of the product is especially important for mobile devices. So if you plan to move the device often or take it with you on holiday, it makes sense to go for a smaller model. Larger models are impractical for longer transports or take up unnecessary space.

Power supply

Most devices are battery-powered. Most give you a signal when the battery is low and needs to be replaced.

When the battery is weak, the accuracy of the measurement decreases.

The signal is in the form of a light signal on the detector or appears on the LCD display.This can often be overlooked as less attention is paid to these devices in everyday life.

Some models are therefore equipped with lithium batteries. If your sensor has a lithium battery, you no longer need to worry about the power supply, as the battery will last as long as the built-in sensors.

Sensor life

The sensors are very sensitive and only last for a certain amount of time. After this time, you should replace your detector to avoid any risk. This is because outdated sensors can trigger false alarms or, in the worst case, fail to sound an alarm. When buying a detector, you should therefore pay close attention to how long it will last. The service life for sensors is a maximum of 10 years, whereby this value varies greatly depending on the model.

When buying, this is one of the most important criteria, because if the sensors no longer work after 2 years, you have to buy a new CO detector.

It is worth investing in models with a long service life, as this means you do not have to replace the CO detectors every few years

Operating temperature

The operating temperature tells you at which temperatures the CO detector is still fully functional.

Most detectors function in a range between 0°C and 45°C. For example, if you are installing the detector in a room that is not heated, you should check to see if the temperature falls below 0°C. If it does, you should replace it. If this is the case, you should make sure when buying the detector that it also works at minus temperatures.

Memory function

This function is there to tell you whether an increased value has occurred during your absence or whether an alarm has possibly been triggered. This function is especially helpful if you are often away from the house for a longer period of time.

Because even a small increase in CO detectors should be taken very seriously. They can be an indication of a dangerous source.

LCD display

Having an LCD display gives you more options for using the CO detector. If you want more than just an alarm when the threshold value is exceeded, then it makes sense to choose a model with a display.

Features such as the current ppm value and the battery level can be quickly read on a display. Operating the detector is also easier if you can see what you are doing.

Application area

It is important to consider where the detector is to be used. Not every detector can be used in every area. You should also pay attention to where you want to use detectors, because they are not needed everywhere.

Decision: What types of CO detectors are there and which is the right one for you?

In the following, we will provide you with an overview of the different models, which should help you with your purchase.

What distinguishes a standard CO detector and what are its advantages and disadvantages?

Standard CO detectors are designed to trigger an alarm when a dangerous amount of carbon monoxide is detected. The standard devices usually trigger an alarm in the form of a beep. They are made for indoor use.

Not all standard CO detectors are the same, as some devices have additional features such as an LCD display.

Advantages
  • Signal tone when the carbon monoxide concentration is too high
  • Comparatively cheaper than other models
  • Easy to operate and install
Disadvantages
  • Only signal tone as danger detector
  • Reacts only to carbon monoxide
  • Signal tone may not be heard at a greater distance

What distinguishes a networked/smart CO detector and what are its advantages and disadvantages?

Networked/smart CO detectors can be connected to other CO detectors in the home. In addition, Smart CO detectors can be controlled with an app and as soon as a signal is triggered, the owner receives a message on the mobile phone. This means that an alarm triggered on one device is forwarded to the others and thus gets a wider range.

Advantages
  • Long range
  • Can be extended at any time
  • Smart CO detectors also provide notification when the owner is away
Disadvantages
  • Cost-intensive
  • Radio signal can be interfered with
  • To work perfectly, all CO detectors should be from the same brand

What are the advantages and disadvantages of a combination of smoke and CO detectors?

Another option is a combination of smoke and CO detectors. This means that fewer devices need to be installed in the household. However, certain things must be taken into account.

Smoke and carbon oxide behave differently. This can lead to problems with the placement of the device. This is because smoke detectors should be placed higher up in the room, while CO detectors should be about head height.

Advantages
  • Can alarm for more than just carbon monoxide
  • Less equipment on the walls
  • Less work for installation and maintenance
  • False alarm risk is reduced
Disadvantages
  • Hard to find a suitable place
  • Costly

What are the features of a mobile CO detector and what are its advantages and disadvantages?

Mobile CO detectors can be transported and do not have to be permanently mounted on a wall or ceiling. Firefighters, rescue services and chimney sweeps often use mobile CO detectors for their missions.

But mobile CO detectors can also be purchased for private use. These are well suited for travelling, as they are usually very small and light.

Advantages
  • Can be taken anywhere
  • Compact
  • Can also be used in mobile homes and cars
Disadvantages
  • Mostly they are not radios, so cannot be connected to others

This is not directly a CO detector, but an additional module that can be connected to networkable devices.

As soon as an alarm is triggered, the module receives a radio signal and starts to generate strong light flashes, thus creating an additional optical signal. In addition, there is a vibration pad that can also send an alarm while sleeping.

Advantages
  • Safety for the hearing impaired
  • Vibration cushion for sleepers optional
  • Free choice of mounting, as no values are measured with it
Disadvantages
  • Extra costs for the module
  • Cannot measure values itself

Guide: Questions you should ask yourself before buying a CO detector

When buying a CO detector, there are many things for you to consider, as this should not be an impulse purchase. In the following, we have selected some questions that we think are relevant.

Why is a CO detector useful?

Carbon monoxide detectors can save lives. Carbon monoxide is a poisonous gas that is odourless and colourless. This gas can lead to life-threatening situations if the gas is not detected. Due to the properties of carbon monoxide, it is difficult to detect the gas without an appropriate device. Smoke dete ctors are not CO detectors. Smoke detectors do not alarm when carbon monoxide levels are too high.

Kohlenmonoxid Melder-1

Gas cookers are a potential source of danger, so make sure you have a working flue
(Image source: pixabay.com / Image: PhotoMIX-Company)

Carbon monoxide is produced during combustion processes of substances containing carbon such as wood, oil and petrol. In addition, carbon monoxide is highly flammable. These situations can arise in households due to defective gas cookers or gas heaters, for example. These defects are often not discovered immediately and thus lead to dangerous situations.

A CO detector is also useful during the winter time, as most people air their homes less during this time and heat more at the same time. This increases the danger.

Carbon monoxide value Symptoms
30 ppm Max. Permissible value in Germany
200 ppm Mild headache within 2 to 3 hours
400 ppm Headache within 1 to 2 hours
800 ppm Nausea, dizziness and twitching within 45 minutes
1600 ppm Nausea, dizziness and headache within 20 minutes, death within 2 hours
3200 ppm nausea and dizziness within 15 minutes, death within 30 minutes
6400 ppm nausea and dizziness within 5 minutes, unconsciousness and death within 20 minutes
12800 ppm unconsciousness after 2 to 3 breaths, death in under 3 minutes

Who needs a CO detector ?

In principle, anyone who wants to protect themselves against carbon monoxide. Especially in flats and houses where gas combustion is still used. CO detectors serve as a safety measure against the poisonous gas and are a precautionary measure.

It is also important to have a CO detector in garages and basements, as the concentration of the gas can rise very quickly there. So that a dangerous situation can be avoided.

A CO detector is particularly useful in flats with gas heating and fireplaces, as combustion takes place there.

There are also professions where a CO detector is a must. For example, chimney sweeps and firemen are dependent on a CO detector.

How does a CO detector work?

Sensors are built into a CO detector. They detect the concentration of carbon monoxide in the air by means of an electrochemical process. As soon as the threshold value is exceeded, an alarm is triggered.

All CO detectors are based on a fixed standard. This standard was laid down in EN 50291 and applies to all common devices on the market. In addition, there is a time delay for weak values.

There are also CO detectors available in the trade that are equipped with a pre-alarm. This indicates even small amounts of carbon monoxide in the air, which is not yet dangerous to humans. These are indicated by a light signal or as a value on the display and not yet by an alarm sound.

Co levels time to alarm
30 ppm alarm within 2 hours
50 ppm alarm within 60 to 90 minutes
100 ppm alarm within 10 to 40 minutes
300 ppm alarm within 3 minutes

How much does a CO detector cost?

The price range for CO detectors is very wide. Standard CO detectors can be bought for just under 15 euros, but other CO detectors could be purchased for over 150 euros.

When buying a CO detector, the quality should be the main consideration, not the price.

Of course, there are also differences in size and quality. Therefore, about 40 to 100 euros should be budgeted for the purchase.

However, the choice of a CO detector should not depend on the price, because the price also varies greatly depending on the area for which the CO detector is needed and with which features.

Therefore, the choice should depend on the quality and your needs. After all, in case of an emergency, it is important that the alarm is triggered in time. In the course of this article, the different types will be presented.

Where should a CO detector be placed?

CO detectors should be placed where carbon monoxide can be produced. Most CO detectors are mounted on the wall. It is important that you place the CO detector where it is easily visible. Also, the CO detector should be placed at least 1.5 metres away from the potential source of danger.

Kohlenmonoxid Melder-2

Carbon monoxide is produced by combustion in fireplaces, so it makes sense to install a CO detector here.
(Image source: pixabay.com / keresi72)

They should be mounted on the wall at a height of about 1.5 to 2 metres. It should also be noted that the detectors should not be placed directly next to a window or a fume cupboard, otherwise the results may be distorted.

The CO detector should also be at least 15 cm away from the ceiling and at least 30 cm away from the nearest wall.

How many CO detectors are needed?

Simply put, CO detectors are needed wherever carbon monoxide can be produced. This means that if a household has several carbon monoxide sources, all sources should be protected with one CO detector.

It is not necessary and also not sensible to have a detector in every room, because this only increases costs unnecessarily and at the same time does not increase safety.

However, each floor should have one.

Furthermore, you should note that the detector must not be laid flat or behind furniture or curtains. Otherwise the carbon monoxide value cannot be measured correctly.

What requirements must a CO detector meet?

It is important for a CO detector to comply with the EN 50291 standard. All devices must comply with this standard. This European standard specifies general rules such as construction and operating behaviour. The CE marking is another characteristic of a good CO detector.

It is also important to note the serial number or code of the device, which indicates the date of production. Furthermore, it is important to be able to trace the origin of the CO detector. Therefore, the name and address of the manufacturer should be known.

A seal of approval from TÜV is another sign of good product quality.

CO detectors are also counterfeited. Look for the appropriate markings on the product and if you are not sure, ask a professional

What alternative options are there to a CO detector?

Gas and smoke detectors are no substitute for a carbon monoxide detector. However, an alternative is to combine the detectors. It is possible to buy a device that is a smoke and CO detector in one. However, a combination device is not necessary in most cases, as smoke detectors are already compulsory in almost every building and most homes are already equipped with them.

How is a CO detector properly installed?

In this section, we will show you how to properly install a CO detector in your home. Most of the time, you will receive installation instructions for your device when you buy it. You should follow these instructions.

It is always important that the CO detector is not installed next to a window or an air vent, otherwise the measurement results can be falsified.

In rooms with open sources of danger, such as a fireplace, the CO detector should be at least 1.3 metres away from the source of danger. It should also be mounted on the wall higher than the door. You should also ensure that the detector is at least 15 cm from the ceiling and at least 30 cm from the nearest wall.

In rooms such as bedrooms and living rooms without an open source of danger, it makes sense to install the detector at a height of about 1.5 metres and 1.7 metres. The detector should not be covered by furniture or curtains.

What to do if the CO detector sounds the alarm?

It is important to remain calm. Panic will not solve any problems. But alarms should always be taken seriously in order to minimise health hazards.

  1. Open all windows and doors: Do this only if you do not put yourself in danger
  2. Leave the building: Make sure everyone has left the building, but do not put yourself in danger
  3. Call the local emergency services: Here you can usually contact the fire brigade. In some cities
  4. Wait: Do not re-enter the building until it has been cleared by the emergency services.

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Carbon monoxide is very toxic to humans. Get to safety immediately and let the emergency services deal with the situation.
(Image source: pixabay.com / Jennifer Beebe)

Image source: KINGMA/ 123rf.com

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