Smoke Alarms

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The lack of a smoke or carbon monoxide alarm can have tragic consequences. Every home should have both, as they can detect smoke and harmful chemicals in the air before you detect them yourself, notifying you and allowing you time to get yourself and your loved ones to a safe location. There are several types and features available in the smoke and CO alarm market these days. Examine all your options before choosing the one that's right for you.

Types of Smoke Alarms

CO alarms are meant to detect carbon monoxide in the air, a must-have device in any home with fuel-burning appliances such as a furnace, water heater, range cooktop or grill. Even an all-electric home may benefit from a CO alarm, because using a generator during a blackout or a gas power washer after a flood produces CO.

Ionization smoke alarms are smoke alarms that create a conductive chamber with the use of radioactive materials. The conductivity of the chamber will fluctuate when particulates such as those associated with smoke enter the air, and if it detects a particulate level that may be dangerous, then it triggers a siren.

Photoelectric smoke alarms are meant to detect the large particles typical of smoky, smoldering fires. However, they are poor at detecting fast, flaming fires. They are less prone to false alarms from burnt food and steam, though, so you can use them around the kitchen or bath.

Dual-sensor smoke alarms combine ionization and photoelectric technology to save you the hassle of installing two separate smoke detectors. However, they do not detect carbon monoxide, so users will still need a separate CO alarm in their home.

Combination smoke/CO alarms can detect smoke as well as carbon monoxide. However, combination smoke/CO alarms will typically only detect one type of fire, either smoldering or flaming, but not both. If you buy a combination CO and ionization alarm, then you should also buy a separate photoelectric unit, and vice versa.

Important Smoke Alarm Features

  • Power source: Hardwired smoke and CO alarms tie into your home's wiring and require professional installation, usually at a cost of about $250 per unit. Battery-only alarms are simpler to install, and they also work during a power failure. They require a yearly replacement. Lithium batteries, on the other hand, will last the life of your alarm. Plug-in alarms are also available, but they are inconvenient in the fact that outlets are typically low on the wall, and optimal alarm placement is on or near the ceiling.
  • Low-battery warning: This is essential for all battery-powered units. The settings will warn you when the battery is low and needs replacing, either with a warning chirp, a "low battery" voice message or a visual display.
  • Interconnectability: You can link some smoke and CO alarms so that they all alarm when any one is triggered, an ideal feature if you have a large home. If a fire starts or if CO rises to an undesirable level anywhere in the home, then the alarms will alert people throughout the house. Some newer homes even have wiring already in place to link alarms. For those without, you can buy alarms that interconnect wirelessly.
  • Digital CO display: This will constantly display the area's CO concentrations in parts per million, even when the concentrations are below the level that triggers the alarm. The display can give you an early heads up if the CO level is inching up or is higher than usual. Some also show the peak level since they were reset, warning you of any spikes that occurred while you were away from home.
  • Hush button: The most common feature on smoke alarms, the hush button is extremely convenient for when the alarm is being a nuisance. It is much more convenient than disabling the unit, which actually risks later malfunction and leaves open the possibility that you'll forget to turn it back on. However, hush buttons should not be available on CO alarms, because carbon monoxide levels should never be ignored.
  • Strobe alarm: A strobe alarm is a great option for smoke and CO alarms for those who are hearing impaired. Some have an integral strobe light, while others accept add-on units. Strobe lights are also helpful for heavy sleepers, because the intense light streams are likely to wake you up.
  • Remote-control mute: Available on some CO and combination CO/smoke alarms, remote-control mute allows users to use their television remote control to silence a nuisance alarm, a convenient feature if your alarm is too high to reach.
  • Overall security system: You can incorporate some smoke and CO detectors into a system that sounds an alarm outside and inside the house. It can also have a monitoring service notify the police or fire department, or even call your cell phone, when an alarm is tripped.

Smoke Alarm Cost

You can buy smoke and CO alarms at most hardware and home-improvement stores, in addition to online. They are relatively inexpensive, starting at around $12 for basic models. CO alarms cost more, however, about $40 and up. Special features like strobe alarms, digital displays and interconnectability will add to the overall cost. Interconnectability, for example, will add $5 to $10 to the cost of each unit. Before making any alarm purchase, always check to make sure the alarm meets Underwriters Laboratories standards. Smoke alarms should meet UL Standard 217, and CO alarms should meet UL Standard 2034. Also look at the manufacture date on the back of the alarm. The fresher the device, the better its performance, as these devices lose their sensitivity over time.

Last Updated: July 22, 2011
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About Emelie Battaglia Emelie Battagila is a contributing writer for

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