Kidde KN-COPP-3 Nighthawk Plug-In Carbon Monoxide Alarm with Battery Backup and Digital Display

We had had them for years and they ALWAYS read 0. When we started seeing it detect CO we knew we had a problem. Occasional low readings (such as near your kitchen on Thanksgiving if you have a gas stove) are ok, but any consistant reading is cause for real concern particularly if it is away from any known source of CO (stove, fireplace, etc).

I strongly reccomend folks place a detector on each occupied level of your home. If something happens you may very well get different readings on different levels (I did).

When selecting a CO detector be sure to pick an electornic one with a digital readout. They cost more, but are well worth it. The only maintenance with a unit like this one is replacing the backup battery. (BTW, a backup battery is a really good idea. Each year many folks die because they used various types of gas heating devices during power outages with inadequate ventalation.) Also, the digital readout will help track down problems envolving lower levels of CO and may give you earlier warning of a malfunctioning heating system.

Finally, this particular unit has an advantage in that it can be placed directly over an outlet, or the included power cord can be used to allow higher wall mounting or placement on a table/shelf/etc.


Battery problem solved   January 16, 2006
T. Jones (Wildwood, Mo United States)
74 out of 74 found this review helpful

I also had a problem with my two detectors using up the batteries in one to two months time. But I called Kidde customer service and after I gave them the model no and assembly dates from the back of the units, they confirmed that these models were defective. Apparently there is a faulty circuit that triggers the low battery indicator prematurely. So the batteries are actually not worn down completely. The problem is with the sensor that reads the battery levels. Kidde sent me two new detectors. They are working fine so far. I will know more after a couple months. If you have this problem, call Kidde customer service and they should take care of you.


An Excellent Alarm providing great feeling of safety   March 27, 2000
48 out of 49 found this review helpful

This alarm seems to be everything it claims to be. Initially plugged it in my garage until I brought it inside. The alarm went off when the garage door was closed too soon after our car was pulled out. I bought this before I read a great review on this product in Consumers Reports. This is a great product


The best Carbon Monoxide on the market.   July 25, 2000
canaduck (The Great White North)
87 out of 96 found this review helpful

I got this to protect my family and myself from any potential CO hazards. We have gas heat, fireplace, and stove. We had a cheaper model with those stupid cartridges. One day it went off and my wife called the police to ask what to do. Within 5 minutes, there were 3 police cars, 2 fire trucks, a rescue truck, and 20 firemen, paramedics, and police officers at the house. The neighbors all came out and the police had to direct traffic around all the vehicles parked in front of the house.

It was a false alarm, the cartridge was old and became saturated with CO over a long period of time (a common problem). Worse yet, the replacement cartridge cost almost as much money as a new unit. What a waste of money.

This one has a nice digital display and doesn't need a replaceable cartridge. I bought one for my parents to.

Get a CO detectors. The added security is well worth the money.


CO Detector False Alarms   January 14, 2001
Peter J. Romano (Yonkers, NY USA)
36 out of 38 found this review helpful

I have had this detector for a few years and it has worked flawlessly. I have always had very low CO readings in my house since it is 75 years old now. Recently, my wife while in the house, was talking on her Cellular Phone, and walked within 5 feet of this detector, and it set off the detector and caused the detector to generate false readings from the radiation that the Cell Phone was producing. She actually saw the display, displaying a series of random numbers, as she was talking on her cellular phone. We also have 900MHz cordless phones in the house and these do not appear to affect the detector.