Carbon monoxide poisoning is the leading cause of accidental poisoning deaths in America, according to the Centers for Disease Control. To combat this, Kidde recommends installing a CO alarm on every floor of your home, as well as 5-20 feet from sources of CO such as a furnace, water heater, or fireplace. For more information on placement, check out Placement of CO Alarms.
Many states have specific laws about CO alarms. See what the laws are where you live.
Once you've decided on a location for your alarm, here's how you get it into place:
There's a mounting base that has screw holes to allow you to fasten the base in your chosen location. Select a drill bit slightly smaller than the size of the included wall anchors to ensure a snug fit.
Use the base to help mark where the screw holes will go, then drill the holes in the marked placements.
Using a hammer, tap the plastic screw anchors provided into the drilled holes.
Drive the screws partially into the anchors, and line up the mounting base with the screws.
Install the batteries, then place and twist the alarm into position, tightening with a screwdriver.
Now that your alarm is in place, be sure to properly maintain it.