Smoke and Carbon Monoxide Alarms Buying Guide

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Smoke and carbon monoxide alarms can be lifesavers. (Photo: @KorneevaKV via Twenty20)
Nearly two-thirds of deaths in home fires happen in properties without working smoke alarms, according to the National Fire Protection Association (NFPA). In addition, carbon monoxide (CO) is an invisible, odorless gas that sickens 20,000 to 30,000 people each year and kills at least 500, according to Forbes. This means it’s important to install smoke and CO detectors throughout your house to keep yourself and your family safe.

Battery-Operated vs. Hardwired Detectors

When choosing a smoke or CO detector, you need to determine what kind of power source you want to use.
  • Battery-operated detectors: Smoke and CO detectors that use batteries sound a tone, usually a chirping, to let you know when the battery life is low. Regardless, you should test a detector at least once a month and replace the batteries if necessary.
  • Hardwired detectors: Hardwired detectors are tied directly to the power supply of your home. If the power goes out, a hardwired detector uses a battery backup. Just like with a battery-operated detector, you need to test a hardwired version at least once a month to make sure the battery still works.
  • Plug-in CO detectors: Some CO detectors plug into an electrical outlet. Just like hardwired models, plug-in detectors also have a battery to act as a backup in case of a power outage. You should test the device to make sure the battery is still good at least once a month.

Types of Fire Detectors

  • Photoelectric smoke detector: A photoelectric detector uses light reflecting off smoke particles to detect danger. This happens when the light produced by the bulb of the detector reflects back into the photocell.
  • Ionization smoke detector: An ionization detector identifies the presence of smoke by ionizing air particles in the vicinity of the detector. When attaching to smoke particles, the electric flow through the ionized particles is changed, setting off the alarm.

Types of Carbon Monoxide Detectors

  • Biomimetic detector: Biomimetic detectors use a synthetic hemoglobin that darkens in the presence of CO. You can find two types of biomimetic detectors: Those you have to look at to determine if CO is present and those that connect to a light sensor and sound an alarm if CO is present in the air.
  • Electrochemical detector: An electrochemical CO detector uses an electric current to determine the amount of CO in the air. When CO levels reach a high level, this highly accurate detector lets you know by sounding an alarm.
  • Semiconductor detector: In a semiconductor detector, the presence of elevated CO levels in the air allows a higher current to trigger an alarm by reducing resistance in a semiconductor sensor.

Common Smoke and Carbon Monoxide Detector Features

Once you decide on the type of detector you want to install in your home, you need to determine what other features you want, if any.
While all smoke detectors sound an alarm when smoke is present, some offer additional features such as:
  • Interconnectivity between detectors
  • Display screen
  • Low-profile or micro-design model
Some of the more common features in CO detectors are:
  • Interconnectivity between detectors
  • Voice alert
  • Digital display
  • Five-year lifespan (or longer)
As you can see, you have a lot of choices when picking the right smoke or carbon monoxide detector for your home. The most important thing to remember when maintaining detectors in your home is to check them regularly to make sure they are working properly, and to change them out when they malfunction. This can help protect you and your family from a fire or harmful carbon monoxide in your home.