Smoke alarms only help if they are in the right places and working. Fire safety groups including NFPA, the U.S. Fire Administration and the CPSC agree on the basics: inside every bedroom, outside each sleeping area and on every level. This guide covers placement, interconnected alarms, kitchens, carbon monoxide alarms and when to replace them.
The basic rule
NFPA, the U.S. Fire Administration and the CPSC all give the same core placement advice.
Inside every bedroom
Outside each sleeping area, such as the hallway outside the bedrooms
On every level of the home, including a basement if there is one
Ceilings and walls
Smoke rises, so alarms go on the ceiling or high on the wall. The USFA advises mounting them on the ceiling or high on the wall. Follow the manufacturer’s instructions for exact spacing from corners and peaks, since these vary by model.
Keep alarms away from places where air movement can push smoke away from them, such as right next to a ceiling fan or an air supply vent. The instructions that come with the alarm list these spots.
Kitchens and nuisance alarms
Alarms that go off every time someone makes toast are a real safety problem, because people take the batteries out. NFPA advises keeping smoke alarms at least 10 feet from a cooking appliance to reduce false alarms.
If an alarm goes off while you cook, the USFA says not to remove the battery. Open a window, press the hush button, or have the alarm moved farther from the kitchen.
Interconnected alarms
Interconnected alarms are linked, so when one sounds, they all sound. NFPA and the USFA both recommend them. If a fire starts in the garage or a back bedroom, you hear it right away in your own bedroom, even with the door closed.
Interconnection can be done with wiring between hardwired alarms or with listed wireless alarms that talk to each other. Many newer homes already have hardwired, interconnected alarms with battery backup. Older homes may have alarms that only sound in the room where they are.
Types of smoke alarms
There are two main sensing types. Ionization alarms tend to react faster to flaming fires. Photoelectric alarms tend to react faster to smoldering fires. The USFA recommends having both types, or dual-sensor alarms that have both.
Carbon monoxide alarms
Carbon monoxide has no color or smell. Homes with gas appliances, a fireplace or an attached garage, and anyone who might run a generator during an outage, should have CO alarms.
The CPSC recommends CO alarms in a central spot outside each separate sleeping area and on every level of the home. Combination smoke and CO alarms are available and can save space on the ceiling.
Testing and replacement
Alarms wear out. The sensors lose sensitivity over the years, even if the test button still beeps.
Test each alarm monthly with its test button
Replace batteries at least once a year, unless the alarm has a sealed 10-year battery
Replace the whole smoke alarm 10 years from the date of manufacture printed on the back
Follow the manufacturer’s replacement date for CO alarms
If an alarm chirps, it usually needs a battery or has reached the end of its life
Common placement mistakes
Walk through your home and look for these gaps.
A bedroom with no alarm inside it, often a guest room or a room turned into an office
Only one alarm for a long hallway that serves bedrooms at both ends
An alarm so close to the kitchen or a bathroom door that steam or cooking sets it off
Alarms that are older than 10 years, or with no date you can read
Smoke alarms only, with no CO alarm in a home with gas appliances or an attached garage
Alarms painted over or covered by decorations
Help with high ceilings and testing
Climbing a ladder to test or change an alarm is a fall risk, especially on a high or vaulted ceiling. It is fine to ask family or an electrician to help. Some people choose alarms with sealed long-life batteries or hardwired alarms so there are fewer battery changes overhead.
How Solana Electrical can help
Our electricians install hardwired smoke and CO alarms, replace old alarms that have reached the end of their life, and add interconnection so every alarm sounds together.
Call us at (602) 999-2770 and a real person answers, any hour. Tell us how many alarms you have and how old they are, and you will hear the price before anyone drives out. Our work carries a two-year warranty on labor and material, and we are licensed under AZ ROC #341966.
If a smoke alarm sounds and you see or smell smoke, get out and call 911 from outside. If a CO alarm sounds, move everyone outside to fresh air and call 911.
Common questions
How many smoke detectors does a home need?
At least one inside every bedroom, one outside each sleeping area and one on every level of the home. Larger homes may need more.
How far should a smoke detector be from the kitchen?
NFPA advises keeping smoke alarms at least 10 feet from a cooking appliance to cut down on false alarms.
How often should smoke detectors be replaced?
Replace smoke alarms 10 years from the manufacture date on the back of the alarm, and test them every month.
