Smoke and Carbon Monoxide Detectors to the Rescue

A small price to pay for saving lives

Smoke and Carbon Monoxide Detectors

A smoke alarm can make the difference between life and death. Every home should have smoke alarms in good working condition; in fact, many cities and states require them. You should probably also have at least one alarm for carbon monoxide (CO)–a colorless, odorless gas emitted by fuel-burning devices that has been dubbed the “invisible killer.” When in good working order, a fuel-burning appliance such as a stove or oven, water heater, furnace, or boiler produces little CO. But if the device isn’t working properly, it could be emitting dangerous levels of fumes. A car left running in an attached garage is also a hazard.

At home

  • Install smoke alarms in the right places. Put a smoke alarm on every level of the home, in every bedroom, and outside the bedroom areas. Err on the side of more alarms rather than fewer; they’ll provide better coverage of the whole house and give you earlier warning of a fire. But don’t put them in the garage, kitchen, or bathrooms, where false alarms can be triggered by car exhaust, cooking, and humidity.
  • Install CO alarms in the right places. In smaller one-story homes, one CO sensor in a central location is sufficient. In larger homes, install one on each level in a central location. Don’t install CO alarms next to windows or exterior doors; fresh air flow can cause readings to be lower than in the rest of the house. And don’t put a CO alarm in the garage; starting a car may set the alarm off.
  • Make sure your alarms work. The Consumer Products Safety Commission says millions of American homes have smoke alarms that don’t work, usually because of dead or missing batteries. If your alarms have batteries, test them monthly by pushing the test button. Replace the batteries annually.
  • Replace old alarms. Replace smoke alarms every 10 years and CO alarms every 5 years. Check the back of the alarm for the date it was manufactured.┬áCombination CO and Smoke alarms purchased after April 2007 should have a built-in end of life warning that will alert you to the need to purchas a new one after 5 years.

When shopping, look for

  • UL listing. To ensure quality, buy smoke and CO alarms that are certified by Underwriters Laboratories (UL).
  • Dual-sensor smoke alarms. Smoke alarms come with two types of sensors. Ionization sensors detect small particles produced by flaming fires. Photoelectric sensors detect larger particles from smoky, smoldering fires. The safest strategy is to install both types of sensors, or to buy a dual-sensor unit that uses both technologies.
  • Power options. The most basic smoke and CO alarms run on batteries that need to be replaced every year. Plug-in models are convenient for CO alarms, but don’t make as much sense for smoke alarms, which work best when mounted near the ceiling. Hardwired alarms are also available, and some building codes require them in new homes. If you choose plug-in or hardwired alarms, make sure they have a battery backup in case the power goes out. For larger homes, interconnected alarms (either battery-powered or hardwired) are a good idea; if there’s a problem in one part of the home, all the alarms will sound throughout the home. Some home security systems include smoke alarms.
  • Extra features. Some alarms have both a beeping alarm and a voice alert. If you think anyone in your household is likely to sleep through the beeping alarm, the voice alert might add another level of safety. For people with hearing impairments, there are smoke and CO alarms equipped with flashing lights.

Other Considerations

  • Fuel-burning appliances should be installed according to local building codes by trained professionals. It’s a good idea to have your heating systems inspected annually by a heating professional or your utility company. Be wary of a stove with orange instead of blue flames. It isn’t burning the gas completely and is producing too much CO.
  • Ionization smoke alarms contain a very small amount of a radioactive material called americium-241. The U.S. EPA says these devices are safe and pose no radiation health risk as long as you don’t tamper with the alarm or try to remove the americium. When disposing of an alarm of this type, discuss your options with your local recycling department or household hazardous waste facility.


…to your health
Smoke and CO alarms save lives. About two-thirds of the people who die in home fires in the United States each year were in homes without working smoke alarms. About 140 people die every year from unintentional CO exposure.

Early signs of CO exposure are similar to cold or flu symptoms, and include fatigue, headache, dizziness, shortness of breath, and nausea. If you suspect you’re being sickened by CO, leave the building immediately and call the fire department. Symptoms of CO poisoning will usually go away if you leave the building, whereas if you have the flu or a cold, you’ll still feel sick.

…to your wallet
Smoke and CO alarms are one of the least expensive life-saving purchases you can make. Smoke alarms start at about $7. You’ll spend $25 and up for a dual-sensor (ionization and photoelectric) smoke alarm, a CO alarm, or a combined smoke/CO alarm.

Less expensive CO models beep when CO exceeds threshold levels for a certain period of time. In addition to beeping, the more expensive CO alarms have digital displays that show the CO levels in parts per million.

Common Mistakes

  • Misusing appliances. Never use gas generators, camp stoves, or charcoal grills indoors, even if the windows are open. And never use them in an enclosed or semi-enclosed space like a garage, basement, or crawlspace. Never use a gas stove, oven, or clothes dryer to heat your home. Be extremely careful if using an unvented, portable kerosene heater for emergency or localized heat–unlike furnaces, kerosene heaters don’t have flues to vent exhaust gases. If using a kerosene heater, follow the manufacturer’s safety directions and always have a CO alarm in the room.
  • Idling a car in the garage. CO fumes from a car that’s left running in an attached garage for an extended period of time can kill the occupants of the house–even if the garage door is open.

Getting Started

When moving into a new home, test the alarms to make sure they are working. Check the back for the manufacturing date and replace them if you have a CO alarm more than five years old or a smoke alarm more than ten years old. If there is no date, replace them unless you know they are new.

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  1. Irene P. December 14, 2009
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  8. bennie January 15, 2010
  9. Dean Dennis February 5, 2010
  10. Jeff August 3, 2010
  11. Dirk Flail February 9, 2011
  12. Nelson May 8, 2013

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