Smoke Detector Buying Guide

Smoke detector types

Smoke detectors come in two basic types: ionization and photoelectric, also known as optical. Most experts recommend using a dual smoke detector that combines both detection systems.

Ionization smoke detectors contain a small amount of radioactive material that ionizes the air within the device and triggers the alarm when the airflow is interrupted. These alarms are best at detecting high-flaming fires caused by flammable or combustible liquids (such as gasoline or acetone), paper or electricity. Ionization smoke detectors are usually battery-powered and are the least expensive type of alarm, with different models ranging from $7-$10.

Photoelectric smoke detectors use a beam of light and a sensor that triggers the alarm when particles interrupt the beam. These alarms respond to smoky, flameless, slow-starting fires, such as those caused by smoldering clothes, bedding, upholstery or curtains. Photoelectric smoke detectors are more expensive than ionization detectors, with prices averaging about $30.

It is best to buy a smoke detector that contains both ionization detection technology as well as photoelectric detection technology for places where both flaming and smoky fires are possible. These “dual” smoke detectors are often more expensive than single detection alarms, but it is more cost effective to buy a dual smoke detector than it is to purchase two separate units. Dual smoke detector prices start at around $40.

Combination smoke and carbon monoxide detectors are also available. These types of detectors track carbon monoxide, a clear, odorless, poisonous gas produced in homes by things like heating equipment and stoves. At high levels, carbon monoxide can poison a person, potentially resulting in death. Combination carbon monoxide and smoke detectors usually use ionization to detect smoke and should be supplemented with a photoelectric smoke detector.

Smoke detector features

Any smoke detector you purchase should be UL listed. This certifies that the smoke detector has been tested and approved by Underwriters Laboratories, a nonprofit organization that inspects and rates electrical and fire safety equipment according to recognized standards.

Some models can be connected to other smoke detectors in your home. This feature is called interconnectivity, and when an alarm is triggered in one room of a house, all the other smoke detectors in the house will also be triggered. The obvious benefit is that everyone in the house is warned when there is a fire; however, there are some setup limitations depending on power supply. If you live in a condo or an apartment, you probably won’t need a smoke detector with this feature.

Remote-control smoke detectors save the hassle of climbing up to the ceiling when you want to test the batteries or turn off the detector after a false alarm. For windowless hallways and bedrooms, consider a smoke detector with an exit light that illuminates the way to safety.

If you have small children or teens, consider a smoke detector that allows you to record a message that plays instead of the traditional beeps. According to a recent study published in Pediatrics, children between the ages of 6 to 12 are more likely to wake up to a recording of a parent’s voice than to a smoke detector’s screeching.

For some installations, look for a smoke detector with a feature called Intelligent Sensing. This differentiates nonthreatening conditions, such as bathroom steam or small amounts of kitchen smoke, from real emergencies and also runs a daily, automatic self-check test.

Power supply

The two main ways of powering your smoke detector are batteries or the household’s power source. Battery-powered smoke detectors are more common and are much easier to install. However, you risk having the batteries fail without your knowledge unless you change them twice a year. To prevent this, change all your smoke detector batteries at daylight savings time or routinely change them on a family member’s birthday. Ionization smoke detectors have the added benefit of sounding when the battery starts to fail.

Smoke detectors that are connected to the household’s power source can be more reliable. Look for smoke detectors that are backed up by a battery power source, in case the household power fails—a common occurrence in electrical fires that start near the main or fuse box. A common power source also allows smoke detectors to be interconnected. You’ll need an electrician to help you install hard-wired smoke detectors, and the cost of installation could run up to $1,000, depending on your home’s wiring.

Smoke detector placement

A general rule of thumb is to have one smoke detector on each habitable level of your home. If you only need one smoke detector in your home, a dual detector will cover you for all types of fires. If you need several smoke detectors, it might not be necessary to have a dual alarm in all locations.

Since ionization smoke detectors are best at detecting high-flaming fires, they are best placed near storage closets, garages, kitchens and bathrooms. Never place these smoke detectors in the kitchen or bathroom, as cooking or hot water steam could set off a false alarm. Photoelectric smoke detectors, best at detecting smoky fires, should be placed near bedrooms, living rooms and clothes closets.

While every home should have at least one dual smoke detector in a central location, smoke detectors in other spots can be suited to the type of fire that is more likely to occur at that location. Tailoring your smoke detector placement this way can help save money.

Shelf Life

The National Fire Protection Agency recommends replacing your smoke detector every 10 years. Individual models promise a different shelf life, with some smoke detectors guaranteeing longer-than-average lives. In the all-too-common event that you fail to purchase a new smoke detector after 10 years of use, these longer-life alarms could give you a little extra leeway.

Need to know more?

• Buying a Smoke Detector
  http://www.epa.gov/rpdweb00/sources/smoke_buying.html
• Product Safety Tips: Smoke Alarms
  http://www.ul.com/consumers/smoke.html
• Fire Escape Planning
  http://www.nfpa.org/categoryList.asp?categoryID=393&URL=Research%20&%20Reports/Fact%20sheets/Escape%20planning