Kidde 10SCO Combination Smoke & CO Alarm review

£16.00Typical price

Test result

PASS
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verdict: Outstanding

The Kidde 10SCO combination smoke and CO alarm is built to detect both smoke and carbon monoxide. This review covers how it fared in our tests when challenged to detect carbon monoxide back in 2018. It’s powered by a 9v battery and comes with a 10-year warranty and will sound to let you know when it’s reached the end of its working life. Read on for our full review to find out how this Kidde smoke and CO alarm fared in our  detection tests.

Pros
  • Outstanding at detecting all of the levels of CO we tested it with and continues to sound reliably even after being exposed to lots of CO. It also worked well after three months of usage.
Cons
  • None that we found in our tests – this alarm sounded at the right time in every single one of our tests.
This Kidde alarm did a fine job of detecting carbon monoxide in our tests. We set it the challenge of detecting a rising amount of the gas, from a very low level where the alarm shouldn’t sound, right up to levels that could kill. Each time we tested it, the Kidde 10SCO aced our tests and that’s why we’re very happy to make it a Best Buy as a carbon monoxide alarm. As a smoke alarm it wasn’t bad at all, but just fell short of breaking into Best Buy territory. So, don’t worry about this alarm not being a brand new design – it might be a 2018 model but it’s still one of the better alarms that we’ve tested.

Unbranded Carbon Monoxide Alarm 1 review

 

 

 

£8.99Typical price

Test result

FAIL

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 verdict: Unresponsive to carbon monoxide – Don’t Buy

We have tested six alarms that look like the alarm pictured here between 2016 and 2018 and each has failed to detect the presence of carbon monoxide reliably in our tests. If the CO alarm in your home looks like the one shown, you will need to replace it because our tests prove that it’s likely to be unsafe. We’ve given alarms that look like this one our Don’t Buy warning, based on the six seemingly identical alarms that failed our CO tests.

Pros
  • None – this is an unreliable carbon monoxide alarm that you shouldn’t buy.
Cons
  • Everything we’ve seen in our testing shows that alarms that look like this can’t be relied upon to detect carbon monoxide (CO).
Alarms that look like the one featured here may come with an unfamiliar brand name, or be unbranded, and the packaging can vary from alarm to alarm. But everything we’ve seen in the tests we’ve carried out on six alarms that look like this leads us to believe that they are the same products – and will regularly fail to detect carbon monoxide.We’ve tested six versions of this alarm that we bought for less than £10 from Amazon and eBay. Each of the alarms we tested, first in 2016 and then again in 2018, failed to reliably detect carbon monoxide. Because of this, we have made all alarms that share this design Don’t Buys.

Each alarm we’ve tested has come with instructions which wrongly advise consumers to not install the alarm in the kitchen, where in many UK homes you’ll find a gas boiler, which could be a potential source of carbon monoxide (CO).

 

Unbranded Carbon monoxide alarm 2 review

 

 

£6.00Typical price

Test result

FAIL
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 verdict: Doesn’t detect CO every time – Don’t Buy

This carbon monoxide (CO) alarm is dangerous and failed to detect CO in two of our carbon monoxide detection tests.  Following these gas detection failures, we’ve made it a Don’t Buy and our advice to you is to steer well clear of it. If you have one in your home, you should replace it with a well-known brand from a high street store or reputable online retailer.

Pros
  • None – this is a dangerous alarm and should be avoided.
Cons
  • Inability to detect carbon monoxide reliably
  • Unhelpful and potentially dangerous instructions.
This unbranded and dangerous carbon monoxide alarm is a Don’t Buy. It failed to detect the deadly gas twice in our CO detection tests. The failed tests involved testing it with a catastrophic concentration of CO and then seeing whether it could recover and work normally afterwards. In our tests, we found that it failed to detect the huge amount of CO and then failed to detect a lower concentration of CO and sound the alarm. We’ve made it a Don’t Buy because of these gas detection failures.

Unbranded Carbon monoxide alarm 3 review

 

 

£11.00Typical price

Test result

FAIL

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 verdict: Failed to detect carbon monoxide three times in our tests

This carbon monoxide (CO) alarm failed to sound in one of our initial carbon monoxide detection tests and also failed to respond and sound the alarm in two later gas tests. Because of this, we’ve made it a Don’t Buy. It’s sometimes known as the JKD-512COM, and in other listings it’s unbranded. Our tests show that you can’t rely on it to detect carbon monoxide every time, so our advice is to give it a very wide berth. If you have one in your home, replace it as soon as possible with an alarm from a well-known brand, and buy from a high street store or reputable online retailer.

Pros
  • None – this alarm can’t detect carbon monoxide reliably.
Cons
  • Poor at detecting carbon monoxide in our tests
  • Too quiet
  • Unhelpful and potentially dangerous instructions.
This unbranded carbon monoxide (CO) alarm failed to detect CO in three of our gas detection tests. The first failure was when we set it the challenge of detecting a potentially lethal, but low amount of the gas. Later failures were recorded when it failed to detect a huge concentration of the gas and then failed to detect a lower amount. The consequences of an alarm like this failing to sound in your home when you need it to don’t bear thinking about, and that’s why we’re making this dangerously unreliable alarm a Don’t Buy. Head over to our Best Buy carbon monoxide alarms to find the best alarm for you.

Unbranded Carbon monoxide alarm 4 review

 

 

£11.00Typical price

Test result

FAIL
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 verdict: Avoid this alarm – Don’t Buy.

This dangerous carbon monoxide (CO) alarm cannot be relied upon to detect CO and then sound the alarm when you need it to. That’s why we’re making it a Don’t Buy. It failed to detect CO in 17 of our detection tests and can’t be trusted to alert you if there’s a build-up of the deadly gas in your home. If you have this alarm, you should replace it as soon as possible with a model from a well-known brand.

Pros
  • None – this alarm poses a danger to the lives of anyone who has one in their home.
Cons
  • Inability to detect carbon monoxide reliably
  • Too quiet
  • Potentially unsafe instructions.
This dangerous carbon monoxide (CO) alarm has failed 17 of our CO detection tests. What’s more, the instructions don’t meet the requirements of the carbon monoxide alarms standard, and when it does sound it’s too quiet. So, all things considered, this cheap and nasty alarm is the epitome of a Don’t Buy and should be avoided.

Unbranded Carbon monoxide alarm 5 review

 

 

£5.00Typical price

Test result

FAIL

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 verdict: Unreliable at detecting carbon monoxide – Don’t Buy

Bought from an online marketplace, this is yet another cheap and unbranded carbon monoxide (CO) alarm that you simply can’t rely on to detect CO. We’ve made it a Don’t Buy, as our test results show that after failing to detect CO three times, it’s more likely to endanger lives than to save them. If you have one in your home, replace it with an alarm from a well-known brand that’s available on the high street or from reputable online retailer.

Pros
  • None – this dangerous alarm isn’t sensitive enough to detect CO reliably.
Cons
  • Very poor CO detection in our tests.
This cheap, nasty and above all dangerous alarm failed to sound in three of our CO detection tests. The instructions give the wrong advice on where to site it, too. It failed to sound in the presence of a huge amount of CO and then failed to recover and sound with a lower concentration of the gas. And in our 90 day test, where the alarm is tested on day one of testing and again on day 90, we found that it again failed to detect the gas. If our test results are mirrored in your home, this alarm would simply fail to detect CO reliably enough. That’s why we’ve made it a Don’t Buy and are warning consumers about it.

Lifesaver Carbon Monoxide Alarm 5CO review

£17.00Typical price

Test result

PASS
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 verdict: Excellent

The Lifesaver Carbon Monoxide Alarm 5CO comes with replaceable batteries that you’ll need to change every two to three years during its seven-year lifetime. In return for this upkeep, you’d expect to be able to rely on the Lifesaver Carbon Monoxide Alarm to live up to its reassuring name. To find out if this trust is justified, we tested it back in 2016 against four different levels of the poisonous gas in our test lab. Read on for the results of our test of this Lifesaver carbon monoxide alarm.

Pros
  • Excellent at detecting all levels of carbon monoxide
  • Loud enough for all to hear and robust enough to recover from a catastrophic gas incident to keep on working reliably.
Cons
  • None. During three months of testing
  • This alarm didn’t reveal any weaknesses.
This reliable and loud carbon monoxide alarm did brilliantly in our tests, which is why it’s a Best Buy. It detected all levels of carbon monoxide in our 30+ lab tests, it recovered well to sound again following exposure to a huge amount of the gas and it was just as effective at the end of our three months of testing as it was on day one. So, don’t let the fact that it’s a few years old now get in the way of you buying an excellent carbon monoxide alarm.

Unbranded Carbon monoxide alarm 6 review

Product alert

Don’t Buy this carbon monoxide (CO) alarm – it failed to sound in all 38  of our carbon monoxide detection tests

This alarm simply can’t detect carbon monoxide (CO) and should be avoided. In our tests it failed to detect the gas every single time and that’s why we have made it a Don’t Buy.

£8.00Typical price

Test result

FAIL

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 verdict: Dangerously unreliable – Don’t Buy

This unbelievably dangerous carbon monoxide (CO) alarm failed to detect the deadly gas in every single one of our 38 tests. That’s why we’re making it a Don’t Buy. We bought it from eBay, but it’s also available from other online marketplaces. If you have an alarm that looks like this in your home, your best course of action is to replace it with an alarm from a well-known brand that you buy from a high street shop or reputable online retailer.

Pros
  • None – this is a dangerous carbon monoxide alarm that you should avoid.
Cons
  • Inability to detect carbon monoxide reliably.
This alarm simply can’t detect carbon monoxide (CO) and should be avoided. In our tests it failed to detect the gas every single time and that’s why we have made it a Don’t Buy. And like many of the other alarms that we bought from online marketplaces, the instructions are misleading and potentially dangerous. So, ignore the cheap price and don’t buy this dangerously unresponsive alarm.

Unbranded Carbon monoxide alarm 7 review

£12.00Typical price

Test result

FAIL

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 verdict: Dangerously unresponsive – Don’t Buy

This unsafe carbon monoxide (CO) alarm failed to detect the deadly gas in all but one of our tests – registering 37 failures to detect CO and sound the alarm – so we’re making it a Don’t Buy. We bought it from eBay, but it’s available from other online marketplaces too. In common with a collection of other cheap and unbranded alarms that we have bought and tested through this kind of site, you simply can’t rely on it to detect carbon monoxide when you need it to. If you have an alarm that looks like this in your home, replace it with a well-known brand from a high street store or reputable online retailer. 

Pros
  • None – this is a dangerously unreliable smoke alarm.
Cons
  • Unable to successfully and reliably detect carbon monoxide
  • Too quiet
  • Misleading and potentially dangerous instructions.
This is yet another unresponsive and downright unsafe carbon monoxide (CO) alarm that we bought from an online marketplace. It failed all but one of our CO detection tests, so in your home you just wouldn’t be able to trust it to alert you about a potentially deadly build-up of the gas. It’s far too quiet when it does sound and the instructions are potentially misleading. This alarm is one of the more worrying and dangerous products that we’ve tested, because of this we’ve made it a Don’t Buy and we would strongly advise you against buying it.

Kidde Carbon Monoxide Alarm 7CO review

£19.99Typical price

Test result

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 verdict: Very good indeed

You’ll need to replace the batteries in the Kidde Carbon Monoxide Alarm 7CO every two to three years, but in return it promises a decade of faithful service. So, is this 2016 carbon monoxide detector a worthwhile investment? We tested its ability to alert you to the presence of carbon monoxide in a series of exacting tests, and assessed the clarity of its alarm and installation instructions. Check our results to discover if this carbon monoxide detector has what it takes to be a Best Buy alarm.

Pros
  • Excellent at detecting carbon monoxide
  • Durable
  • Resilient and loud enough for everyone to hear when the alarm sounds.
Cons
  • None. During our extensive lab tests
  • We found no drawbacks to this model.
This brilliant carbon monoxide alarm passed all 30+ gas detection tests we set it, including detecting low, middling and high levels of the gas. It was loud enough to wake the whole house and we liked the fact that it was just as good at detecting carbon monoxide on day 90 of our tests as it was on day one. All in all, a clear Best Buy and one for your shortlist despite its advancing years.

Unbranded Carbon monoxide alarm 8 review

 

 

£8.00Typical price

Test result

FAIL

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 verdict: Dangerously unresponsive – Don’t Buy

This a Don’t Buy carbon monoxide alarm and it should be avoided. In our tests it failed to detect the deadly gas a worrying 27 times. It doubles as a <a href=”https://www.which.co.uk/reviews/smoke-alarms/unbranded-smoke-alarm-in-blue-box”>smoke alarm</a> and it was just as bad when we tested its smoke detection abilities. We bought it from a seller on eBay, but you’ll also find it listed on other similar online marketplaces. If you have one in your home, replace it with a well-known brand from the high street or a reputable online site.

Pros
  • None – this is a dangerous alarm and one to avoid.
Cons
  • Not sensitive enough to detect carbon monoxide reliably.
This alarm is one of the more dangerous products we’ve ever tested. It’s both a carbon monoxide detector and a smoke alarm, and in the past year we’ve tested it in both modes. As a smoke alarm, it failed to sound in any of our eight smoke detection tests. And in our CO detection tests it failed to sound in 27 of our 38 CO detection tests and even when it does sound, it’s far too quiet. It’s one of the most obvious Don’t Buys we’ve seen and it’s one to avoid.

X-Sense CO03D review

 

 

 

£25.00Typical price

Test result

FAIL

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 verdict: Failed to detect CO every time – Don’t Buy

The X-Sense CO03D carbon monoxide alarm failed to sound in one of our carbon monoxide tests when we tested it in 2018. Because of the safety concerns we have based on the gas detection failure in our tests, we’ve made this X-Sense alarm a Don’t Buy. This product failed to sound when in the presence of a catastrophic concentration of carbon monoxide and all three of the samples of alarm we tested failed in the same way.&nbsp;

Pros
  • It failed one of our carbon monoxide tests and passed all of the rest of them. But one failure is enough for us to slap a Don’t Buy warning on it.
Cons
  • Three samples didn’t detect a huge concentration of carbon monoxide and that’s why we have made this alarm a Don’t Buy.
This alarm did a good job in almost all of our carbon monoxide detection tests, but due to it not being able to detect CO when exposed to a huge amount of the killer gas, we’ve made it a Don’t Buy. Your best bet is to pass on this model and to go for a Best Buy carbon monoxide alarm instead.

FireAngel CO-9B review

£14.00Typical price

Test result

PASS
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 verdict: An excellent alarm

The FireAngel CO-9B Carbon Monoxide Alarm will last for seven years before you need to replace it, although you’ll need to change the batteries once or twice during its lifetime. It may need a touch more maintenance than some other carbon monoxide detectors, but does it reward your efforts with effective carbon monoxide detection? We tested it back in 2016, so read on for our test results.

Pros
  • Outstanding at detecting low and high levels of carbon monoxide
  • Reassuringly loud
  • Just as good at detecting the gas on day 90 as it was on day one.
Cons
  • Our three-month-long tests uncovered no weaknesses with this detector
This excellent carbon monoxide alarm might be advancing in years, but it did a great job of detecting the gas in our tests. It’s a worthy Best Buy and you’ll have no problems hearing it when it sounds. We also liked how well it recovered from being exposed to a catastrophic amount of carbon monoxide, as it continued to work reliably even after such an event.

FireAngel CO-9D review

£18.00Typical price

Test result

PASS
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 verdict: Recommended

The FireAngel CO-9D Carbon Monoxide Alarm has a sealed battery, which means you’ll never have to buy replacements during its seven-year lifetime. It sounds like a convenient buy, but does it deliver where it really matters? To find out if you can trust this 2016 carbon monoxide detector when you need it most , we tested its reactions to different levels of carbon monoxide in a series of stringent safety tests.

Pros
  • Detects carbon monoxide regardless of the amount in the room
  • Very loud
  • Reliable and resilient enough to recover from a catastrophic amount of carbon monoxide.
Cons
  • Our three month-long tests uncovered no weaknesses with this alarm.
This carbon monoxide alarm might be a few years old now – we tested it back in 2016 – but we still have no hesitation recommending it to you. It sailed through all of our gas tests and detected carbon monoxide every time we set it the challenge. It’s a product that we think you can rely on and is therefore a Best Buy model that we would recommend.

FireAngel CO-9X-10T-FF review

£23.00Typical price

Test result

PASS
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 verdict: A very good alarm

If you buy the FireAngel CO-9X-10T-FF Carbon Monoxide Alarm you won’t need to replace it for a whole decade, which is about the top end of any carbon monoxide detector we’ve seen. It’s certainly long-lasting, but is it actually any good at sniffing out the deadly gas? We tested this FireAngel carbon monoxide detector back in 2016 to find out. Read on for the results of our carbon monoxide gas detection tests.

Pros
  • Excellent at detecting carbon monoxide
  • Loud enough to wake up the neighbours
  • Reliable and robust enough to recover from a serious gas incident and continue to detect well.
Cons
  • Our three-month-long tests didn’t uncover any weaknesses in this alarm’s performance.
This is a long-lasting carbon monoxide alarm that our test results show you can rely on. It’s up to the task of detecting both high and low levels of the deadly gas, it recovers admirably from exposure to super-high concentrations of carbon monoxide and you won’t have any problems hearing it when it goes off.

FireAngel CO-9X review

£19.00Typical price

Test result

PASS
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 verdict: Excellent in our tests

If you’re looking for a device that needs minimal maintenance, then the FireAngel CO-9X Carbon Monoxide Alarm may well catch your eye. It has a sealed battery, which means you won’t have to replace the batteries during its seven-year lifetime. We’ve tested its detection of killer carbon monoxide in a series of stringent lab tests back in 2016 to see if it pairs convenience with the quick reactions you need to keep you and your family safe in an emergency. Read on for the results of our tests.

Pros
  • Brilliant at detecting different levels of carbon monoxide
  • Reliable
  • Loud enough for all to hear
  • And robust enough to recover and continue to work following a serious carbon monoxide leak.
Cons
  • None. Our three-month-long tests uncovered no weaknesses with this alarm.
This excellent carbon monoxide alarm passed all of the 30+ gas tests it was faced with, sounding its alarm at the right time every single time. It has a loud alarm, and is robust and reliable. It was as sensitive to the threat of CO on day 90 of our tests as it was on day one and all of this makes it a worthy Best Buy. It might be a little long in the tooth now – we tested it back in 2016 – but it’s still one of the best carbon monoxide alarms we’ve seen, so don’t allow age to be a barrier.

Aico Ei208 review

 

 

 

£21.00Typical price

Test result

FAIL

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 verdict: Imperfect in our tests

The Aico Ei208 carbon monoxide alarm failed to sound in one of our 2018 carbon monoxide tests and that’s why we’ve made it a Don’t Buy. In one of our tests, we flooded three of the Aico alarms with a catastrophic level of carbon monoxide to which they responded correctly and sounded. But later, when we tested them with a lower but still dangerous level of the gas, none of the three alarms sounded. Aico told us that it’s concerned, that it takes all matters of alarm quality and reliability very seriously, that all of its alarms are independently tested, it hasn’t had a problem with these alarms since they were launched in 2010, and that it is confident its alarms meet the carbon monoxide alarms standard.

Pros
  • This alarm passed all but one of our tests. But because of the gas detection failure we found in one of our tests
  • We have made it a Don’t Buy.
Cons
  • The alarm failed to recover and sound following being exposed to a very high level of CO.
This Aico alarm failed one of our carbon monoxide detection tests and we have made it a Don’t Buy because of this failure. It passed all of our other carbon monoxide detection tests, but it was unable to recover and continue to sound reliably after exposure to a very high concentration of carbon monoxide.

Kidde Long Life Carbon Monoxide Alarm 10LLCO review

£18.00Typical price

Test result

PASS
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 verdict: First-class

The clue is in the name of the Kidde Long Life Carbon Monoxide Alarm 10LLCO – it should last up to 10 years before you’ll need to replace it. Along the way you won’t even need to replace the batteries, which are safely sealed inside the unit. But does it pair this long life with the ability to detect even small concentrations of carbon monoxide in the air? We put the Kidde carbon monoxide detector through a series of gas detection tests back in 2016 to find out.

Pros
  • Effectively detected carbon monoxide at four different strengths
  • Loud
  • Durable and resilient enough to recover from a carbon monoxide drenching to carry on working reliably.
Cons
  • None. During three months of testing this alarm didn’t reveal any weaknesses.
This Kidde carbon monoxide alarm did a first-class job of detecting the deadly gas in our lab when we tested it in 2016. And even after being presented with catastrophic levels of carbon monoxide, it recovered well to carry on working reliably. It’s as loud as an alarm needs to be, and its 10-year lifespan is impressive, too.

Nest Protect Smoke + CO Alarm review

£89.00Typical price

Test result

PASS
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 verdict: Truly outstanding

The Nest Protect Smoke + CO Alarm can send alerts about dangerous levels of carbon monoxide or smoke direct to your smartphone, which is a handy touch if you’re out of the house at the time. This more advanced two-in-one functionality, along with its 10-year lifespan, pushes the price up far above the price of a standard CO alarm. This review is of how well the Nest detects CO, but it’s also a smoke alarm and since testing it, the law on smoke alarms has changed in Scotland. This means that as the Nest doesn’t come with a heat detection function, it won’t be suitable for Scottish homes from 2022. We put the Nest Protect Smoke + CO Alarm through a series of stringent carbon monoxide safety detection tests to find out how well it detects the deadly gas. Read on for the results of our tests.

Pros
  • The smartphone alerts work well
  • It’s great at detecting various levels of carbon monoxide
  • Survives extremely high levels of the gas and is loud enough for everyone to hear.
Cons
  • Only the high price
  • But it is two products in one and will last for 10 years.
An innovative product that worked brilliantly as a carbon monoxide alarm in our tests. The alarm sounded exactly when it was meant to and a message was received by our smartphone around 30 seconds later. It’s loud enough and was as good at detecting the gas on day 90 of our tests as it was on day one. It’s also a Best Buy as a smoke detector, but from 2022, due to a change in Scottish law, it won’t be suitable for homes in Scotland as one.

FireAngel W2-CO-10XQ review

£49.99Typical price

Test result

PASS
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 verdict: Responsive and impressive

Offering a market-leading 10-year lifetime, the FireAngel W2-CO-10XQ promises a full decade of service before you need to replace it. Does it pair this long life with a first-class ability to detect poisonous gas? To find out we put this carbon monoxide alarm through a full range of safety tests back in 2016, assessing everything from the clarity of its alarm sound to how sensitive it is to four different levels of carbon monoxide. Read on for our summary of how this FireAngel carbon monoxide alarm fared in our lab tests.

Pros
  • Effective at detecting different concentrations of carbon monoxide
  • Reliable enough to keep on working after being exposed to high concentrations of the gas and loud enough to wake you in an emergency.
Cons
  • It costs around twice as much as other models with a similar lifetime guarantee.
This effective carbon monoxide alarm passed every single one of the 30+ gas tests we put it through and it was just as good at detecting CO 90 days into our testing as it was on day one. It’s loud enough for everyone to hear and we’re delighted to add it the list of Best Buy alarms that we recommend. So, don’t worry about this alarm being a few years old – it might be getting on a bit but it’s still one that we’d recommend to you.

Kidde 4MCO review

£50.00Typical price

Test result

PASS

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 verdict: An excellent alarm

The Kidde 4MCO mains-powered carbon monoxide (CO) alarm is designed to last for seven years before it will need to be replaced. It comes with a rechargeable backup battery so that it will sound even during a power cut. A test button allows you to check it’s working and the alarm chirps to let you know when it reaches the end of its life. It can be connected to other Kidde alarms so that if one detects danger, they will all sound. We tested the Kidde 4MCO – the 4MDCO is identical other than it has a digital display. We tested the Kidde 4MCO back in 2019 to find out how well it detected a variety of concentrations of carbon monoxide. Read on for our verdict on this mains-powered carbon monoxide alarm and to find out whether this is the right alarm for you.

Pros
  • Excellent at detecting both low and high levels of carbon monoxide
  • Loud enough for all to hear.
Cons
  • None in terms of how it performed
  • Mains alarms are more pricey than battery-powered counterparts.
This excellent and dependable carbon monoxide (CO) alarm was outstanding at detecting the deadly gas in our tests. We tested it with concentrations of carbon monoxide from 30 parts to million (PPM), where an alarm shouldn’t sound right through to a catastrophically high concentration of 5,000ppm. In each case this Kidde alarm was superb at detecting the gas and sounding the alarm in good time. It was easily loud enough too, and a worthy Best Buy even if it is a few years old now.

Ei Electronics Ei3018 review

£55.00Typical price

Test result

PASS

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verdict: Very impressive

The mains-powered Ei Electronics Ei3018 carbon monoxide alarm is built to detect CO for five years and has a warranty to cover this. There is a backup rechargeable battery, which kicks in if there’s a power cut. The alarm can be used in a network of other Aico/Ei alarms, so that if one detects danger, they all sound. You’ll need the Ei3000MRF interlink module (£48) to do this, which also sends data to your smartphone regarding when it detects CO. To find out how well this Ei Electronics mains-powered CO alarm detects the deadly gas, we tested it in 2019. Read on for our verdict on this alarm.

Pros
  • Brilliant at detecting carbon monoxide regardless of the amount of the gas we tested it with
  • Easily loud enough.
Cons
  • None we found in our tests
  • More expensive than a battery-powered CO alarm would be.
This is an outstanding mains-powered Best Buy CO alarm. It was excellent at detecting the gas and sounding the alarm in all our CO gas detection tests. It was well able to detect CO and raise the alarm whether being tested with low or high concentrations of the gas. It continued to detect reliably after being drenched with an ultra-high amount of the gas. It was as dependable on day 90 of our tests as on day one, and was more than loud enough.

Honeywell XC100 review

£25.00Typical price

Test result

PASS
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 verdict: A very good CO alarm

The Honeywell XC100 carbon monoxide alarm is built with longevity in mind. It comes with a sealed-in and tamper-proof 10-year battery, so you won’t need to worry about finding replacement batteries for it. It also comes with a backlit warning message in red, which shows through the case. When there’s CO in the air, the Honeywell not only sounds, but also displays the message ‘Alarm evacuate’. But how well does it detect carbon monoxide? To find out, we tested it back in 2018. Read on for the full results.

Pros
  • Detects when carbon monoxide is at dangerous levels and sounded the alarm every time in our tests.
Cons
  • None that surfaced in our tests.
This might be a little long in the tooth but it’s still a very good carbon monoxide alarm. We challenged it to detect CO at a range of concentrations, from very low levels where the alarm isn’t required to sound right up to catastrophic levels and everything in between. In all of our tests this superb alarm triggered when it needed to, it was loud enough and it was as good after three months as it was on day one. And that’s why it’s a Best Buy.