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.

The Kidde KN-COEG-3 Nighthawk is well made, easy to use and well worth the cost! Our home seemed to have had a slight gas odor lingering for a few weeks after having our water heater replaced. We could not tell if it was from that or not though because in weeks prior we began having problems with our gas range. Since we only had a the standard Kidde Smoke Alarm and CO2 Detector installed (in the ceiling) and did not have an explosive gas detector, we picked this one up with hopes it would help us determine where the gas odor was coming from by testing each room for gas levels. Having an alkaline 9 volt battery (included) backup; it can be unplugged from the outlet and moved from room to room for testing. You can plug it right into a 110 volt outlet or slide out a built in stand and sit it on the counter. The moment the battery was installed and the detector was set up to test it with an open gas valve, it emitted a very loud piercing blast! It's sure to wake up even the soundest sleepers!! Fortunately, we were able to determine where the gas was coming from and in turn had the problem addressed and resolved in a timely fashion. Pros: Battery Length, Clear Instructions, Easy Installation, Easy Replacement, Easy to Use, Lots of Features, Plug-in and Battery Backup, Very LOUD!!!!!!!! Cons: Somewhat large but not a deal breaker for me obviously Highly recommend!!

Good: The perfect alarm for a detached garage. Detects smoke, CO, natural gas AND propane, with a display on the front that shows levels of same even when they're too low to trigger the alarm. Alarm is loud enough to hear in the house, eight feet away. Plugs directly into an outlet, or you can detach the power supply and mount the alarm away from the outlet. Pricey, but you get a lot for that price. Bad: Not the most stylish unit. But, in the garage, who cares? At this price point, would have preferred a 10-year lithium backup battery in place of a 9-volt. Bottom line: This is the second unit of this type I've owned, the first reaching end of life after 10 years (CO alarms wear out eventually) and cheeping nonstop to announce same. I tested this one, briefly, with my lawn mower running in a closed garage (with me outside a cracked side door, just in case.) It did indeed start reporting CO levels at around 40 ppm, which steadily climbed until the alarm sounded at about 100 ppm. (Whereupon I held my breath, quickly went in, shut down the mower, opened the big door, went back out and waited until the CO level became too low to measure.) The only additional function I wish it had is a remote link, wifi or whatever, to notify me when I'm unable to hear the alarm. No complaints otherwise. Five stars.