Bests & Worsts Reviews from Amazon

I spent a good amount of time in the fire safety aisle of a local store, reading packages and comparing units before selecting this particular one to replace an aging smoke-only alarm. This one has two different-sounding alarms (3 beeps for fire and 4 beeps for carbon monoxide) and runs on 2-AA batteries. The batteries can be replaced without taking the unit off the ceiling and the compartment won't close without batteries in it. I installed it by myself in just a couple of minutes with a pencil, drill, hammer and flathead screwdriver. It has several features I chose not to use, most involve locking systems to prevent tampering, but it is nice that they are offered. Also has a photoelectric sensor claiming to prevent false alarms from food smoke and shower steam. I think it's a great value for my family's safety. **(12/20/08)**I would like to amend my review. A week after installing, the alarm started "chirping" 3 times at irregular intervals (once at 4:00am Sunday, then Tuesday at 1:30pm). I changed the batteries after a third incident (again in the early morning) and it was fine for another four days. The next time I took it down and noticed the back indicates the 3 "chirps" is to replace the alarm. I have had the thing less than a month and have to replace it already?!?!? What a CROCK! **(12/22/08)**I called and spoke to a rep from First Alert on the phone who explained to me the unit runs a self-test every 90 seconds and if it fails, the alarm 'chirps'. He asked me a few questions and promised me a new unit in a week to ten days. **(1/14/09)** I received a new unit in the mail today, hard to install with my fingers crossed. **(3/3/09)**Another malfunctioning alarm, at five o'clock in the morning. I am through with this junk!! Buy only if you want to replace every 4-6 weeks.