Smoke alarm placement: where to put them, how to test them and when to replace them

Where to put smoke alarms in your home

USFA says to install smoke alarms in every bedroom, outside each separate sleeping area, and on every level of the home, including the basement. The CPSC and the Red Cross give the same advice. USFA adds that a closed door may slow the spread of smoke, heat and fire.

In existing homes where alarms are not yet in place, the Red Cross says to install them at a minimum on every level and outside each sleeping area. It adds that if a fire occurs inside a bedroom, dangerous gases can cause heavier sleep, so for the best protection you should install interconnected alarms in each bedroom and throughout the home.

• Every level of the home, including the basement
• Inside every bedroom
• Outside each separate sleeping area
• Consider placing alarms along your escape path

Ceiling, wall and places to avoid

USFA says to put smoke alarms on the ceiling or high on the wall, and to check the manufacturer's instructions for the best place for your alarm. The CPSC says that in general you should place alarms in the center of a ceiling, or 6 to 12 inches below the ceiling if you mount them on a wall.

Some spots are best avoided. The CPSC says not to place an alarm too close to a kitchen appliance or fireplace, and to avoid locating alarms near bathrooms, heating appliances, windows or ceiling fans. To prevent nuisance alarms, another CPSC leaflet says to install alarms at least 10 to 15 feet from the kitchen range.

Garages are different. USFA says smoke alarms are not required, or designed for use, in garages, and that they can sound there because of changes in temperature and humidity, dust, fumes and insects. Heat alarms respond to high temperatures rather than smoke and are ideal for garages, and many models can be connected to your home's fire detection system.

Which type of smoke alarm to choose

There are two basic types of smoke alarm: ionization and photoelectric. USFA says they detect different types of fires, so it recommends every home and place where people sleep have both types, or dual-sensor alarms that contain both. The CPSC adds that ionization alarms respond quickly to flaming fires, while photoelectric alarms respond more quickly to smoldering fires.

USFA says to choose interconnected alarms, so that when one sounds, they all sound. The CPSC says interconnected alarms are typically connected with a wire, but newer wireless technology can interconnect them without wires. Only qualified electricians should install hardwired smoke alarms.

Alarms run on a disposable 9-volt battery, a nonreplaceable 10-year lithium-ion battery, or your home's electrical system. Hardwired alarms usually have a backup battery, and the CPSC says alarms with battery back-up still protect you during power outages. Your city, county or state may require a specific type of alarm, so check with your local fire marshal. Our smoke alarm comparison lists the options.

Testing, batteries and replacement

USFA says a smoke alarm only works when it is properly installed and regularly tested, and that an alarm with a dead or missing battery is the same as having no alarm at all. The CPSC says smoke alarms most often fail to alarm because of missing, drained or disconnected batteries. Take care of your alarms according to the manufacturer's instructions.

Use the test button. The Red Cross says the test feature tests all electronic functions and is safer than testing with a controlled fire such as matches, lighters or cigarettes. It also says to vacuum cobwebs and dust from your alarms monthly. If an alarm begins to chirp, signaling low battery power, the CPSC says to replace the batteries immediately.

Ready.gov gives different numbers. Its escape plan page says to test alarms twice a year, and its home fires page says to replace batteries twice a year unless you use 10-year lithium batteries. Testing monthly, as USFA, the CPSC and the Red Cross advise, more than covers a twice-a-year test. On batteries, the Red Cross says changing them twice a year will not hurt, but fresh batteries typically last at least a year, so more frequent replacement is not necessary unless the alarm begins to chirp.

Alarms wear out, too. USFA says they need to be replaced 10 years from the manufacture date, and the Red Cross notes that smoke alarms become less sensitive over time. Here is USFA's routine for each type of alarm.

• 9-volt battery: test monthly, replace the batteries at least once every year, replace the entire alarm every 10 years
• 10-year lithium-ion battery: test monthly, replace the entire alarm according to the manufacturer's instructions
• Hardwired: test monthly, replace the backup battery at least once every year, replace the entire alarm every 10 years

Nuisance alarms: what to do instead of removing the battery

If a smoke alarm sounds while you are cooking or taking a shower with lots of steam, USFA says not to remove the battery. Open a window or door and press the hush button, wave a towel at the alarm to clear the air, or move the entire alarm several feet away from the kitchen or bathroom. The Red Cross adds that if nuisance alarms are a persistent problem, you should look for a different type of smoke alarm and make sure alarms are installed in the correct areas of the home.

Smoke alarms for people who are deaf or hard of hearing

USFA says there are alarms for people with hearing loss. These alarms may have strobe lights that flash and/or vibrate to alert those who are unable to hear standard smoke alarms when they sound. If you are deaf or hard of hearing, USFA says to use alarms with a vibrating pad, flashing light or strobe light, which start when your alarm sounds.

Ready.gov says alarms with a vibrating pad or flashing light are available for the hearing impaired, and audible alarms are available for visually impaired people. USFA's advice for older adults is that if you cannot hear your smoke alarm, consider getting one that has a different sound or comes with a bed shaker or strobe light. The CPSC adds that children, older adults and the hearing-impaired may sleep through a fire alarm or may need assistance in escaping, so practice your escape plan at night as well as during the day.

USFA also says to interconnect your alarms so that when one sounds, they all sound, and that caregivers should check the smoke alarms of anyone who cannot do it themselves. The Red Cross now offers fire safety videos and resources in ASL to meet the needs of the Deaf and Hard of Hearing community. See our older adults preparedness guide for more.

Free alarms, carbon monoxide alarms and your escape plan

USFA says some fire departments will install battery-operated smoke alarms in your home at no cost, so contact your local fire department's nonemergency phone number. The Red Cross also lets you sign up for a home fire safety visit, including a free smoke alarm installation, from your local Red Cross, though availability depends on your location.

Pair smoke alarms with carbon monoxide alarms. The Red Cross says to install carbon monoxide alarms in central locations on every level of your home and outside sleeping areas, and to replace their batteries at the same time as your smoke alarm batteries. See our carbon monoxide alarm comparison and carbon monoxide poisoning guide.

When a smoke alarm sounds, USFA says you may have less than 2 minutes to get everyone outside and safe. The CPSC says working smoke alarms and a fire escape plan together increase your protection in a fire, so make and practice a home fire escape plan.