How to Install a CO Detector

By Gene and Katie Hamilton

Tools Required
  • Pencil
  • Drill/drill bits
  • Screwdriver
  • Hammer
  • Ladder
Materials Required
  • Smoke/Carbon Monoxide Alarm

Before You Begin

Below you'll find the instructions to install a CO detector. If you don't want to do the job click Home Advisor, a free referral service that connects homeowners with local prescreened contractors.

  • Step 1 : Decide the best location for the alarm

    Safety experts say install an alarm on each level of a multi-level home, including every bedroom, hallway, finished attic and basement. If you have only one alarm, place it in the hallway outside of the main sleeping area. If someone sleeps with their door closed, install an alarm inside the room so it can be heard. For rooms longer than 30 feet, use two alarms at both ends of the room. Install the alarm at least 15 feet away from any fuel-burning appliance.

    Decide the best location for the alarm

    The best location is on the ceiling, next best is on the wall. Mount the alarm on the ceiling in the center of the room so it's closest to all points in the room because smoke, heat and combustion products rise to the ceiling and spread horizontally. Mount it on the ceiling at a minimum of 4" from the side wall. To install on the wall, use an inside wall with the top edge of the alarm at a minimum of 4" and a maximum of 12 " below the ceiling.

  • Step 2 : Install the batteries

    Install the batteries

    Remove the back of the unit and hold the mounting plate and twist it counterclockwise (left) to open the cavity for the batteries. Some alarms require a 9-volt transistor battery, others use a series of AA size batteries. Use only long life alkaline batteries. Insert them in the battery compartment following the battery polarity markings on the bottom of the compartment. Put the - end of the battery at the end marked - and the + end at the + mark. When installed correctly the alarm beeps once and the red LED light flashes. After 20-30 seconds the green LED light flashes indicating the unit is operational.

  • Step 3 : Install the base plate

    Install the base plate

    Remove the mounting plate from the back of the alarm by holding the rim of the mounting plate and twisting counterclockwise (left). Hold the mounting plate against the wall or ceiling location and mark the center of the holes with a pencil. Drill a hole through the pencil marks and use the screws and plastic wall anchors provided by the manufacturer to mount the base plate. Tap the anchors into the holes, put the plate in place, insert the screws into the anchor and tighten them.

  • Step 4 : Align the alarm on its base plate

    Adjust the alarm with the mounting plate and rotate clockwise (right) until the unit is aligned.

  • Step 5 : Test the alarm

    All units have some sort of testing device, usually it's a test button. Press the test button to verify it sounds. Be careful. The alarm is loud so stand an arm's length away from the unit when testing. Press the test/reset button for five seconds and a series of beeps will sound. Some units have a voice alarm and announce "Fire! Fire!" or "Warning! Carbon Monoxide", followed by additional alarm beeps. Then reset the alarm to activate the peak level memory.

    Illlustrations courtesy of Kidde Safety