Over a year ago I purchsed a new Kidde Nighthawk Premium plug-in CO detector (Model 900-0076 AC) for my house. Initially it seems to work fine, but after several weeks it started giving single beep every hour or so.
At first I thought the battery was dead so I replaced it with a new one. It didn't help.
So, I called Kidde who, based on the error code on the LED display, immediately sent me a new unit (didn't even ask for the defective one to be returned).
Then the story repeated itself after several weeks. I called Kidde again and again they sent me another new unit.
Then the story repeated itself after several weeks... At this point I gave up on Kidde, realized that they have an inferior product marketed cleverly and decided not to buy any CO detector for the home until I find something that I am convinced works (I used to have the excellent AIM
So time went by (and we are still alive) and I discover that finally there is some home for a better alternative: Model CO851 by American Sensors.
I also just found the following interesting article:
Thanks! Sam