At the end of last week...my wife, Cherie and daughter Kortney are home both complaining of not feeling well.  They're tired and just feeling sick.  Before laying down and taking a nap...coincidentally, Cherie passes our CO detector and notices some numbers on it.  We didn't realize it at first, but our CO Detector is pretty old (1996).  You're supposed to get it replaced every 5 years.  She finds it odd that it's reading anything and brings the detector out to the garage, plugs it in and it reads 0.  She brings it back into the house and it reads 24.  She calls the fire department. After forcing Cherie and the kids and dogs out of the house, they come in and their CO detectors start going off like crazy, picking up readings of well over 100!  Our detectors were not accurate at all.  After further investigation they find a gas leak in a pipe connected to our water heater.  We had to leave the house and stay in a hotel until the repair was done.  The fireman basically confirmed that I would have gotten home that night to a dead wife, kids and dogs if she wouldn't have noticed those readings and went to sleep.  Problem has been fixed.  I Replaced my CO detectors and even added a few more.  We're all good now.   Moral to the story...make sure you have CO detectors and get them updated every 5 years!!