Although none of the smoke or CO
alarms we tested did everything well
individually, you can combine various
types for optimal protection. Here are
the types of alarms to consider.
CO alarms We found wide variations in
performance, with some models
responding almost twice as quickly as
others in our tests. But any CO
detector is better than none at all.
Ionization smoke alarms The ones we
tested were all excellent at detecting
the small particles typical of fast,
flaming fires, but all were poor at
detecting smoky, smoldering fires.
Ionization units are generally prone
to false alarms from burnt food and
steam, so don't mount them near a
kitchen or bath.
Photoelectric smoke alarms The ones we
tested were all excellent at detecting
the large particles typical of smoky,
smoldering fires, but all were poor at
detecting fast, flaming fires.
Photoelectric units are less prone to
false alarms from burnt food and
steam, so you can use them around the
kitchen or bath.
Dual-sensor smoke alarms These combine
ionization and photoelectric
technology to save you the hassle of
installing two separate smoke
detectors. All the ones we tested were
excellent at detecting smoldering and
flaming fires. But you'll still need
separate CO units.
Combination smoke/CO alarms These can
detect smoke as well as CO. But those
we tested were excellent at detecting
either a flaming or a smoldering fire,
but not both. If you buy a combination
CO and ionization alarm, we recommend
that you also get a separate
photoelectric unit, or vice versa.
Power source Hard-wired smoke and CO
alarms tie into your home's wiring and
require professional installation
(about $250 per unit). Battery-only
alarms are simple to install, and they
work during a power failure, but most
batteries require yearly replacement.
Lithium batteries may last the life of
the alarm. There are also plug-in
smoke alarms. The drawback there is
that electric outlets are typically
low on the wall, while the optimal
placement is on or near the ceiling.
Battery backup A backup battery for
hard-wired smoke and CO alarms offers
security in case of a power failure.
Low-battery warning All
battery-powered smoke and CO units
warn you when the battery is low. Some
provide warning chirps, a "low
battery" voice message, or a visual
display.
Interconnectability You can link
some smoke and CO alarms so that all
go on when any one is triggered. If a
fire starts or CO rises to an unsafe
level anywhere, the alarms will alert
people throughout the house. Some
newer homes have wiring already in
place to link the alarms. In a home
without such wiring, you can buy
alarms that interconnect wirelessly.
Interconnecting alarms are a vital
safety feature in a home with multiple
levels. A standalone alarm may be
adequate for a small, single-level
home.
Digital CO display This important
feature displays CO concentrations in
parts per million, even when the
concentrations are below the level
that triggers the alarm. CO alarms
certified by UL must go off at no less
than 70 ppm, but as little as 30 ppm
may harm heart patients, pregnant
women, and children. 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. Expect to pay a little
extra for this feature: $5 or $10 for
standalone units, slightly more for
units that can be interconnected.
Hush button To silence a nuisance
smoke alarm, pressing a hush button is
more convenient than disabling the
unit, and it precludes the possibility
of forgetting to turn the power back
on. All the smoke alarms we tested had
this feature.
Strobe alarm Strobe lights are the
best warning for the hearing impaired.
Some smoke alarms have an integral
strobe light, and some accept add-on
strobes.
Voice alarm Children tend to sleep
deeper than adults and may not awaken
to a beeping sound. Some smoke and
combination CO/smoke alarms use a
voice command, but it's not clear
whether that's the most effective way
to wake children. According to one
study, many pre-teenagers who slept
through tone alarms awoke to the sound
of their mother's prerecorded voice.
But more research is needed.
Remote-control mute Some CO and
combination CO/smoke alarms can work
with a television remote control to
silence a nuisance alarm.
Safety lights Some smoke alarms
provide path illumination, a plus in
the dark.
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.or even call your cell phone.
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