The best carbon monoxide detectors and alarms: Tried and tested

A truly 'smart detector', the Google Nest Protect is more than just a smoke and carbon monoxide alarm; it's a reassuring presence in your home. With a friendly human voice, it provides early warnings, telling you exactly where danger is. And because it connects to your phone, you'll get alerts even when you're away. If carbon monoxide levels become dangerous, the alarm sounds alongside pulsing red lights to ensure you're aware.

Our Editor, Claire Tapley, tested this for Yours.co.uk and was particularly impressed with its smart features, noting how the built-in pathlight makes nighttime trips easier. Whether heading to the bathroom or grabbing a midnight snack, there's no need to switch on bright overhead lights. She also highlighted how the Nest Protect syncs seamlessly with your phone, allowing you to check a timeline of events and control it remotely. With self-tests running over 400 times daily, it's a set-it-and-forget-it safety measure that offers real peace of mind.

While it may be pricier than other testers included on our list, Claire thinks it's well worth the investment, especially for those already using Nest devices, as they can all be managed from one app.

Upon opening the Kidde 5CO Battery Powered Carbon Monoxide Alarm, I felt like it was easy to use, and I was correct. I slotted in the two batteries that came with the product, and it beeped once (which was so loud that it made me jump) to indicate that it was on and working.

Then, I slotted on the baseplate, pressed the 'TEST WEEKLY/RESET' button to give it a try and it the 'OPERATE' button lit up green, indicating that it was on. It does 4 beeps and then has a five-second pause, before beeping again.

I like its flexibility, as it can be mounted onto the wall with the kit provided, or it can work just as well freestanding, making it ideal for taking with you on holiday if you want some peace of mind.

Unlike some of the options on the list, it doesn't have a digital screen, but this isn't necessarily needed as the light indicators are simple enough to understand.

Reviewed by Yours Commercial Content Writer, Arabella Horspool.

Fireangel's multi-function carbon monoxide detector will provide audible and visual warnings of the early presence of CO in your home. I loved how the LCD screen constantly monitors CO levels, but the real bonus? It also gives you humidity and temperature readings, which are super handy for keeping an eye on your home environment. The LCD screen was easy to read but one slight niggle I have with it is that it doesn't display all the information that it's caple of doing (like the humidity and temperature readings) all on the same screen so you need to cycle through all the displays with the button.

It self-tests the environment so you have peace of mind that it's always doing its job. The self-testing is quite quiet, so there are no annoying beeps while you're trying to relax, just almost-silent reassurance that it's working. The 10-year lifespan means you don't need to worry about changing it every so often, and it's also portable, meaning you can take it with you to a holiday home, etc.

Reviewed by Yours Commercial Content Writer, Arabella Horspool.

Not only is this device modern-looking and sleek, but it's also highly accurate and efficient. Designed in a way to give you the earliest possible warning of carbon monoxide presence, the X-Sense alarm will put your mind at rest. The unit is battery-operated, so there's no need to worry about playing around with wires. Measurements are taken every 10 seconds and are clearly displayed on the large LCD display. Keep in mind that this one is designed to be wall-mounted, so you won't be able to use it freestanding around your home.

I put the batteries in and pressed the test button and boy, was it loud - It has such a loud and high frequency that I'd recommend it for large homes or businesses, as well as those that may be hard of hearing.

Reviewed by Yours Commercial Content Writer, Arabella Horspool.

With a seven-year lifespan, the Mercury 350.139 Carbon Monoxide Detector/Alarm is a fantastic and reliable carbon monoxide detector. It's battery-operated, meaning it will still work during power cuts and provides clear, confident CO readings on the LCD display. Its more compact size and the fact it's battery-operated and freestanding means you can easily move this around your home or take it with you on holiday. The LED lights will beam green for power, amber for fault, and red for alarm, keeping you alert and informed at all times.

It has more of a higher-pitched, faster beep than the other carbon monoxide alarms I tested. One thing that lets it down slightly in my eyes is that the base is quite loose, but that could just have been the one I tried that had this issue.

Reviewed by Yours Commercial Content Writer, Arabella Horspool.

This Kidde Lifesaver Carbon Monoxide Alarm Twin Pack is the same alarm that we've featured above as 'best for flexibility' but it comes in a handy two-pack. You can ensure the safety of your home by equipping it with a crucial defence against the 'silent killer,' carbon monoxide, but equally keep another one in your bag and use it for peace of mind when you're travelling. Both alarms operate using battery power, so it's simple to set them up, but you know they'll also both work during a power cut, too.

While both the Kidde alarms in this duo pack don't have a digital display, when Arabella tested the single one, she found it still had a very clear way to see if carbon monoxide is detected in the home with light indicators as well as a loud alarm. The alarm might make you jump if you're not expecting it, but the loudness is great if you're hard of hearing.