Kidde Nighthawk Carbon Monoxide detector reviews – how to install?


What CO levels does it measure? This CO meter uses an electrochemical sensor and features a clear digital display screen to monitor and record any CO levels in any room of your house. It measures CO levels between 30 and 999PPM, and the display will also indicate if the battery needs to be replaced. When the CO alarm detects carbon monoxide gas, 4 beeps will sound & a number reading will appear on the digital display that measures the CO concentration. These CO levels will be stored it the detectors memory until its reset. Get details in Kidde Nighthawk Carbon Monoxide detector reviews.

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In the box

  • One 9V battery
  • One user manual
  • One CO alarm, model KN-COPP-3
  • One mounting hardware packet (for wall-mount option)

Pros & Cons


  • Three mounting options offer installation flexibility
  • Easy to setup
  • Bright digital display
  • Loud alarm
  • Alerts you when batteries are low
  • Affordable price
  • Digital display
  • Positive customer reviews
  • Backup battery


  • Intermittent beeping noise may take you a while to notice
  • Without instructions, display messages can be confusing
  • Only detects carbon monoxide, not smoke


  • Product Name: Nighthawk Plug-In AC/DC Carbon Monoxide Alarm Detector
  • Product Brand: Kidde
  • MPN: KN-COPP-3
  • Price: $69.99
  • Weight: 1.06 lbs.
  • Product Dimensions: 6.06 x 3.75 x 1.75 in.
  • What’s Included: Carbon monoxide detector and 9V battery


At $69.99, the Nighthawk falls in the higher mid-price range for carbon-monoxide-only detectors but is definitely on the low end if you include smoke/carbon monoxide detectors with smart capabilities. 

Kidde Nighthawk Carbon Monoxide detector reviews


‎ Kidde Nighthawk Carbon Monoxide detector comes with a dimension of 6.06 x 3.75 x 1.75 inches and weighs only 1.04 pounds. It also has a peak level memory, which allows you to see the highest CO level the alarm has detected since its last reset.


Of course, you don’t need to manually check its digital display every now and then. This Kidde carbon monoxide detector emits four 85-decibel beats every five seconds when it detects unhealthy CO levels. It also has a blinking dot to let you know that it’s working and refreshes every 15 seconds to check for any alarming changes.

This CO alarm fits into a standard outlet so that it can be placed anywhere in your home. The plug can be rotated, so the alarm is vertical or horizontal depending on how the socket is mounted. The blinking dot in the lower right corner denotes normal operation. 

Kidde Nighthawk Carbon Monoxide detector Installation reviews

It offers three installation options: direct plug-in, wall mounted, and tabletop. After going through the process ourselves, the direct plug-in and tabletop installations proved to be as simple as they come.

For direct plug-in, all you have to do is open the back, install the battery, and plug the alarm into an outlet. You can even take out the adapter and rotate it so the alarm can be mounted on horizontal outlets. The slide support—located on the back at the bottom—locks into several positions and needs to be used when the alarm is plugged directly into an outlet or used on a tabletop as it supports the alarm’s weight. Sometimes, heavier plug-in devices pull the plug out of the outlet, but we didn’t have this issue so long as the slide was in place. 

The second installation option—wall mounted—is slightly more labor intensive. The alarm includes two mounting screws and anchors (for plasterboard or drywall). If you choose to wall mount, you’ll need a screwdriver or drill. You’ll also have to make sure the alarm is within six feet of an electrical outlet because it still needs to be plugged in to operate correctly.

Tabletop installation is even easier than direct plug-in; you put the battery in, remove the adaptor and cord, plug in the alarm, and set it on the tabletop with the slide support extended.

How does it work?

there are four beeps followed by five seconds of silence before it repeats the pattern. The display then shows the carbon monoxide level—a number between 0 and 999ppm (parts per million). A reading of 0 to 50ppm is normal and safe, 50 to 100ppm isn’t dangerously high but should definitely be addressed. If you see a reading in this range, you need to ventilate the area and immediately find the source of the CO. Anything over 100ppm is dangerously high, and the area should be evacuated. 

Life span

After ten years, the Nighthawk’s end of life alarm will sound repeatedly to let you know it’s time to replace the whole unit. That really gave us some peace of mind. 

Alternate of Kidde Nighthawk Carbon Monoxide detector

Kidde Combination Smoke and Carbon Monoxide Alarm KN-COSM-BA amazon
Need both a smoke detector and a carbon monoxide alarm? Have the best of both worlds at the price of one with the Kidde Combination Smoke and Carbon Monoxide Alarm KN-COSM-BA. While this alarm comes at a pretty affordable price, it doesn’t sacrifice quality over affordability.

This Kidde smoke and carbon monoxide alarm offers a one-of-a-kind feature: a voice alarm. What it does is that it beeps four times and announces “Warning! Carbon Monoxide!” when it detects 100 ppm of CO and for smoke, it generates a loud “Fire!,” flashes the red LED, and beeps thrice. It’s like your best friend helpfully screaming at 85 decibels during emergencies—users happily report that it has saved their lives.

Because this Kidde smoke and carbon monoxide alarm is powered by batteries, it’s easy to mount wherever you like. It also comes with a front-loading battery door, letting you easily replace the batteries without having to dismount the alarm. Plus, it announces “low battery” followed by an alarm chirp so that you’ll know once the batteries need to be replaced.

With a voice announcement system combined with the features of both smoke and CO alarms, this Kidde detector is easily one of the best carbon monoxide detectors of 2021.

  • Includes Kidde KN-COSM-BA combination smoke and carbon monoxide alarm and 3 AA batteries
  • Sensor type Ionization sensor for smoke, electrochemical sensor for CO
  • Power source Battery-powered
  • Voltage 4.5 volts
  • Alarm noise level 85 decibels
  • Color White
  • Dimensions (DIA x W) 5.75 x 1.7 inches
  • Weight 12.8 ounces
  • Lifespan 10 years
  • Warranty 10-year limited warranty

Editor’s recommendations

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