Every home with gas appliances, a fireplace, or wood burning stove should have at least one carbon monoxide detector or at least two if you have an upstairs area. Some localities require carbon monoxide detectors in rental properties and new constructions. In any case, a good detector can be bought for about $25, and is too important to risk your life over so little.
Some carbon monoxide detectors plug directly into an existing wall outlet. Most come with a six foot cord so it can be positioned approximately six to seven feet off of the ground above an electric outlet (we discuss proper placement in another section). Most of the direct plug in detectors have a battery backup in case of a power outage.
Some detectors run completely on batteries. These are convenient because you can place them anywhere you want them without having to be within six feet of an electric outlet. Some newer homes have carbon monoxide detectors hardwired into the electrical system wiring.
You can also interconnect carbon monoxide detectors, like many smoke detectors, to go off when any unit is triggered. If one alarm goes off in the far section of the house, the one in your area will begin to sound also.
Some carbon monoxide detectors have built in smoke alarms, so that one device does the work of two. The alarm will sound if smoke or carbon monoxide is detected.
Always look for the UL symbol. Underwriters Laboratory maintains a database of products tested that meet or exceed product safety standards. All UL listed carbon monoxide detectors must have an audible alarm that sounds when carbon monoxide levels of 150 parts per million (ppm) is maintained for more than 10 minutes, or if levels of 70 ppm are maintained for more than an hour. In other words, high levels for more than 10 minutes or low levels for more than an hour will trigger an alarm. UL listed detectors will sound again if high carbon monoxide levels are still present after six minutes.
If possible, select a detector with a digital display that will show you the actual parts per million amount and alert you to lower levels that will not trigger the alarm. As little as 30 ppm may harm infants, children, elderly and heart patients, but will not trigger an alarm. This will give you warnings of possible improperly functioning appliances or air vents.
Some detectors come with strobe lights for the hearing impaired. Check the batteries on carbon monoxide detectors and smoke alarms at least every six months. Old, wasted batteries are useless in an emergency. And it will always be an emergency that triggers an alarm.