Kidde AC Plug-in Carbon Monoxide and Explosive Gas Detector Alarm | Nighthawk Sensor Technology | Model # KN-COEG-3

I'm about to wax poetic about the "Safety Siren Pro Series 1000" (or whatever demonic device this is). Let's be clear, this thing detects carbon monoxide like a bloodhound sniffs out a dropped hotdog at a picnic. No complaints there. If there's a rogue molecule of CO within a five-mile radius, this thing will know. It's like having a tiny, hyper-vigilant, gas-detecting chihuahua with a PhD in atmospheric chemistry. But, and this is a BIG but, when those batteries start to wane, oh. sweet merciful heavens... it's like a tiny, metal-clad demon has taken up residence in my home. The beeping... the BEEPING... isn't your standard, "Oh, batteries are low, please replace me" chirp. No, this is a sustained, high-pitched, soul-rending wail that sounds like a chorus of dying smoke detectors harmonizing with a dentist's drill. It starts subtly, a little "beep" here, a little "beep" there. You think, "Oh, I'll change them tomorrow." WRONG. You've just signed a pact with auditory torment. Within hours, it evolves into a relentless, rhythmic pulse of pure, unadulterated annoyance. My cat now hides under the sofa, my plants have visibly wilted, and I've started having flashbacks to that scene in Reefer Madness where the guy leaps out the window, convinced he's being chased by jazz demons. I swear, this thing is less a safety device and more a psychological warfare instrument. It's so effective at alerting you to low batteries that you'll replace them out of sheer, unbridled terror. You'll be sprinting to the store, batteries clutched in your trembling hands, like you're carrying the antidote to the apocalypse. Five stars for gas detection, minus a million for auditory assault. If you value your sanity, buy this thing, but keep a fresh pack of batteries on standby, and maybe invest in some industrial-grade earplugs. You've been warned.

Haven't seen such a well engineered product in years. It has a plug that is snug for wall mounting, can be rotated, and can even be detached to use as a power brick. Battery backup and comes with a Duracell battery. Documentation seems like it was written by an engineer a tad, but it's a great product. Has a small kickstand too. As far as plastic goes, it seems like it's very good quality. The test works well. Nice to see 0 PPM of explosive gas in the home. Hopefully I never have to review its detection ability. Great job, Kidde, and please don't let your product slide like 95% of modern companies are.

I didn't have a natural gas detector so I got this one to put in my basement, which is the only place in my home with natural gas. Installation is easy, just plug it in. The plug portion can be removed from the back of the unit and the main part located at a different level than the plug. Natural gas is lighter than air and propane is heavier so they recommend that it be located high in the room if you have natural gas and low if you have propane. A lot of the negative reviewers don't appear to understand when the unit is supposed to sound the alarm. Carbon monoxide is poisonous at high concentrations. Natural gas and propane are not poisonous but can be explosive at high concentrations, the levels are well established. At very high concentrations they can cause suffocation because they displace oxygen. The packaging says that it might take up to 4 hours to sound depending on the concentration of CO, this is consistent with the UL standard. In fact a unit would fail the UL test if it went off within 30 days when there are low levels of CO. This is to minimize nuisance alarms, the alarm wouldn't do any good if people got frustrated and disabled it. The gas detector alarm is specified to sound by the time the concentration reaches 25%, this is below the explosive threshold. Just because there is a heavy gas odor doesn't mean there is an immediate danger. One negative reviewer tried to test it with a cigarette lighter, which typically use butane. This unit is only specified to test for natural gas (methane) and propane. The warranty is 5 years, the unit will stop working after 7 years and should be replaced. This is a safety feature, not planned obsolescence.

Good CO detector, has 12v backup battery and 110 v plug in main power supply with a long (4’cord). This is a replacement for the first one I purchased 5 years ago. These units have a 5 year design life once they are plugged in. After 5 years of operation they automatically stop working and sound an alarm and message to replace the unit. I like the display, bright and legible red lettering and the alarm is loud enough for me to hear it upstairs even though it’s located in the basement. Yes, I will probably purchase again.

Year old, with a bad battery. I ordered and received the unit the same day. It was new old stock (NOS) made late 2024. Not idea. AND even worse, as soon as I plugged it in, the unit alarm started sounding with what looked like an "L6" error display. Turns out that was actually a "L" as in "Low" and "b" as in "battery". So I checked and indeed the shipped bat was low. I replaced it, after calming my family down about false alert, and the unit is now working properly. I'm ordering two more and will update this review if those two are newer and/or have good batteries.