5 Best Carbon Monoxide Detectors

Dubbed the ‘silent killer’, carbon monoxide (CO) is odourless, tasteless and colourless. It is still one of the most prominent causes of death due to poisoning, especially in the developing world. Elsewhere on this site, we discussed our safety checklist for carbon monoxide and where to place a CO detector.

On this page, we give you our opinion on the 5 best carbon monoxide detectors and 2 that you should probably avoid!

Which Carbon Monoxide Detector Should I Buy?

1. Nest Protect Smoke & Carbon Monoxide Alarm (Battery)

  • Manufacturer: Nest
  • Weight: 0.3 kg
  • Dimensions: 16 x 16 x 7.2 cm

The king of smart tech when it comes to smoke alarms and CO detectors. We weren’t going to include this in our list, but we needed to include one smart device otherwise we’d get complaints from those that are looking for smarter devices.

The nest looks very nice and can be mounted on a ceiling. It is visible and will get visitors talking about it. The alarm unit comes with self-tapping screws i.e. no need to pre-drill on plasterboard walls or traditional walls.

Nevertheless, we don’t think most homes need such a device, especially at the price point that they’re usually available for. It is quite gimmicky for what it’s supposed to do e.g. the light ring on the device’s central area will light up every time you walk past it when it’s dark.

For most homeowners, one of the four devices below would be more than adequate.


  • Detects both smoke and carbon monoxide.
  • Phone alerts: low battery, Smoke, CO, failure.
  • 10-year product lifetime


  • Very expensive
  • 6 x AA batteries required (not rechargeables)
  • A bit gimmicky for most households

2. Kidde 10LLDCO Carbon Monoxide Alarm

  • Manufacturer: Kidde
  • Weight: 0.16 kg
  • Dimensions: 11 x 7 x 4 cm

This economical option gets really good reviews. With a built in lithium battery – which is designed to last for up to 10 years – this lightweight alarm comes with a digital display. There are 3 LEDs indicating alarm, operate and fault. An end of life warning will come on, but this is something to be expected towards the end of a 10 year term.

The digital display will show CO levels between 11 to 999 parts per million (ppm). Hopefully your reading will be edging towards zero, but it’s nice to see a read out on the display.

The alarm is priced competitively and comes with a long term guarantee – what more can you ask for?


  • Digital display that shows current CO levels.
  • 10 year sealed battery.
  • 10 year manufacturer's warranty.


  • Some say the battery doesn't last for 10 years.
  • Customer service isn't great for replacements.

3. FireAngel CO-9X Carbon Monoxide Alarm

  • Manufacturer: FireAngel
  • Weight: 0.14 kg
  • Dimensions: 14.2 x 11.7 x 4.6 cm

We’ve found very few faults with this alarm. It’s a really simple to install and use. It’s a good compact size and fits into the palm of your hand.

If you’re looking for an economical and functional CO detector that does exactly what it says on the tin, then you can’t go far wrong with the FireAngel CO-9X. The instructions are clear and it’s easy to maintain. It is wall mountable, but we also decided to leave it next to the boiler on top of a wardrobe. You don’t need to really drill this into anywhere and it looks fine being placed on a shelf.

Two thumbs up from us.


  • Sealed in power - no need to change battery.
  • 10 Year warranty.
  • Lightweight and durable.


  • Some are 7 year lifetimes - check yours is 10.

4. X-Sense CO03D Carbon Monoxide Detector with LCD Display

  • Manufacturer: X-Sense
  • Weight: 0.32 kg
  • Dimensions: 10.7 x 10.7 x 3 cm

This is a very stylish and futuristic looking detector. It comes with a backlit digital display, easily visible during the day or the evening. Easy to set up in minutes and easy to install. It comes supplied with all the screws and plugs and 3 AA batteries.

As for functionality, we tested it out and the readings are very accurate. It reads CO concentration build-ups from 30 to 300+ ppm.

On the downside, this alarm comes with a 5 year warranty, which is a little less than other like for like CO alarms.


  • Easy to set up.
  • Supplied with 3 x AA batteries
  • Looks stylish with a premium feel


  • High pitched beeping sound can be irritating
  • Isn't suitable for ceiling mounting
  • Warranty is only for 5 years

5. Fireangel CO-9D Digital Carbon Monoxide Alarm

  • Manufacturer: FireAngel
  • Weight: 0.12 kg
  • Dimensions: 4 x 12.5 x 7.4 cm

We have another FireAngel CO alarm on our list and for good reasons. This well priced and functional CO aarm doubles up as a thermometer, meaning you can monitor the temperature as well as CO levels.

The FireAngel CO-9D provides early warning of both low or high levels of CO in your property via an LCD display and beeping. The alarm shows low levels of CO from 10 ppm, but maybe this isn’t low enough for some?

The small, portable nature of the alarm means you can use it at home in addition to taking it on holiday to your hotel room, holiday home, caravan or canal boat. It’s better to be safe than sorry!


  • 7 year lithium battery supplied.
  • Large multi-function digital screen.
  • Additional temperature feature.


  • Issues with battery failure - rare, but happens.
  • Not great for low CO readings