Kidde Nighthawk KN-COPP-3 Review

The Kidde Nighthawk KN-COPP-3 carbon monoxide detector has a number of features that we like, and we think you'll like them too when you read this review.

If you like having constant updates of the CO levels in your home, then you'll love the digital display which updates every 15 seconds. The read-out also shows the highest levels recorded since you last reset it.

The digital read out lets you see what's going on even when the alarm is not beeping.

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For detailed specifications download the Kidde Nighthawk KN-COPP-3 Manual.

Kidde Nighthawk KN-COPP-3 Features

  • Single 9v battery backup.
  • 6 foot extension cord so you can mount it at eye level and still have it plugged in to the power supply.
  • The digital read out provides readings from from 30 to 999 PPM (parts per million).
  • It has a self diagnostic function where an LED lets you know whether or not it is functioning correctly - you can also press a button for a manual test.
  • It automatically requires replacement after 7 years of operation - this is a feature you really want because sensors can degrade after that period of time.


  • It comes with Battery back-up which means it doesn't need to be plugged in, and it will also keep working when connected to a power outlet in the event that the electricity fails - which is the most likely time you'll turn to non-electric fossil fuel burning for heating which is also the riskiest time for CO level increases inside the home.
  • Comes with a 5 year warranty.


  • It lets you plug it into a power outlet which can make it tempting to plug it in near the floor - don't do this because you position it at eye level in order to read it easily, and because most importantly that's where you get the most accurate carbon monoxide levels detected.


The Kidde KN-COPP-3 Nighthawk carbon monoxide detector has been on the market for over 7 years and has proven itself to be highly reliable.

Click here to purchase this product on Amazon.

Please understand that you need multiple CO alarms in your home in order to safely cover all the possible carbon monoxide build ups - for more information see Carbon Monoxide Detector Placement Instructions.