How Does A Carbon Monoxide Detector Work?

If you’ve ever asked the question how does a carbon monoxide detector work, then this article will explain exactly how it works, and how it helps keep you and your family safe at home, and free from the potential of carbon monoxide poisoning.

As most of us know by now, carbon monoxide is poisonous gas that has the potential to be a silent killer.

You can’t see it, you can’t feel it, you can’t smell it and you can’t taste it.

So that’s why it is vital you have a working carbon monoxide detector in your home, garage or camper van.

Below is a handy table of contents. Clicking on any of the article headers below will jump you straight to the place on this page you are interested in.

How Does A Carbon Monoxide Detector Work?

So how does a carbon monoxide detector work?

In short, a carbon monoxide detector is made up of the following components:

  • A casing and attachement method, or stand.
  • An electrochemical sensor.
  • A power source.
  • An alarm which produces sound.
  • A Test button.
  • Other features (which vary from model to model) such as low battery alert, smart capabilities.

A carbon monoxide detector works by measuring the amount of carbon monoxide (CO) in the air and sounding an alarm if it reaches a dangerous level.

But how exactly do they do that?

How does it know there is carbon monoxide in the air, and how does it know when too much is too much?

The Sensor

The most common type of carbon monoxide detector found in homes is the electrochemical sensor.

This type of sensor is made up of two electrodes that are separated by an electrolyte solution.

One electrode is made of lead dioxide, while the other is made of porous platinum.

When CO molecules come into contact with the sensor, they react with the electrolyte solution and generate an electrical current.

This current is then measured by the detector’s circuitry, and if it reaches a certain level, the alarm is triggered.

The Power Source

Now, let’s talk about the other components found in a home carbon monoxide detector.

First up, we have the power source.

Most detectors run on batteries (and these are the easiest and cheapest to buy and install), but some are hardwired into the home’s electrical system (which will require an electrician).

It’s important to make sure your detector has a reliable power source and that the batteries are changed regularly.

The Audible Alarm

Next, we have the alarm itself.

This is what lets you know if there’s a dangerous level of CO in your home.

The alarm can be a loud beep, a flashing light, or a combination of both.

Some of the more expensive detectors also have a digital display that shows the current CO level in parts per million (ppm) in real time.

The Test Button

Another important component of a carbon monoxide detector is the test button.

This button allows you to check that the detector is working properly by triggering the alarm.

It’s a good idea to test your detector at least once a month to make sure it’s functioning correctly, and if it’s not, to replace the batteries immediately or replace the detector if it’s past it’s sell by date.

Additional Features

Lastly, some detectors come with additional features like a low battery indicator or a “peak level” memory.

The low battery indicator lets you know when the batteries need to be changed, while the peak level memory stores the highest level of CO detected since the last reset.

This can be useful information for technicians trying to diagnose problems with your appliances.

How Is Carbon Monoxide Created In My Home?

I’ve looked at the question how does a carbon monoxide detector work, but how is carbon monoxide created in the first place?

As I’ve already stated above, CO is a colourless, odourless, and tasteless gas that can be extremely dangerous when it’s present in high concentrations in a small area.

People die in the UK every year due to carbon monoxide poisoning in their homes, their garages, their camper vans or their narrowboats.

Below is a table of recorded deaths from carbon monoxide poisoning over the last few years, taken from the Office Of National Statistics.

carbon monoxide deaths chart uk

As you can see, as a country, we’ve got better at preventing deaths from CO poisoning, yet, in 2020, 116 people needlessly lost their lives because they didn’t have a functioning CO detector in their home, van or narrow boat.

And I say needlessly with a real heavy heart – every single one of those deaths were 100% avoidable.

Carbon monoxide is produced by incomplete combustion of fossil fuels like natural gas, propane, and petrol, as well as in any appliance where wood, charcoal or oil are burned.

how a carbon monoxide detector works

And unfortunately, it’s pretty common in homes since many appliances use these fuels, such as gas fires, wood burners, water heaters, gas boilers and gas stoves.

Using and operating BBQ’s or camping stoves inside, and turning on car or motorbike engines or lawn mower engines in your garage or outbuilding, can also cause a build-up of carbon monoxide, especially if

How To Detect Carbon Monoxide?

So, how do we detect CO? Well, that’s where a home carbon monoxide detector comes in.

I’ve already written an excellent article on the best carbon monoxide detectors for home use (UK Top 3), so if you haven’t already got a CO detector, now’s the time to check that article out and buy one.

However, a carbon monoxide detector is not just for homes. Camper vans, van conversions, narrowboats and garages should all be equipped with a working CO detector.

In addition to having a detector, there are other steps you can take to reduce your risk of CO poisoning.

Make sure your appliances are properly installed and maintained (like getting your boiler serviced regularly for example), and never use a gas-powered generator or grill inside your home or garage.

It’s also a good idea to have your chimney inspected by a professional at least once a year, if you have one.

Carbon Monoxide Poisoning

Carbon Monoxide poisoning isn’t easily spotted if you don’t know the symptoms, but even if you do know the symptoms, some of them are quickly dismissed because some of them are common low level medical nuisances that we all suffer from now and again.

The symptoms are:

  • headache
  • dizziness
  • feeling sick or being sick
  • feeling weak
  • confusion
  • chest and muscle pain
  • shortness of breath

If you experience any of these symptoms, open all windows and doors immediately, go outside and seek medical advice.

How Does A Carbon Monoxide Detector Work uk homes

If you think one of your gas appliances is leaking and you have a problem with carbon monoxide, call the free National Gas Helpline immediately on 0800 111 999.


So in short, that’s how a carbon monoxide detector works and all the components that make it up.

Remember, it’s extremely important to have a functioning CO detector in your home.

CO poisoning can cause symptoms like headaches, dizziness, nausea, and even death. And since CO is odorless and tasteless, you won’t know it’s there without a detector.

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My name is Richard.

I'm 40 years old. And I have nearly 20 years experience in various safety and security industries.

I'm here for you, sharing all my knowledge and experience to help you create a safe and secure home for you and your family.

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