Key takeaways
- Smoke alarms go inside every bedroom, outside each sleeping area and on every level, including the basement.
- Get both ionization and photoelectric sensing, or dual-sensor alarms, and interconnect them if you can.
- Test monthly and replace smoke alarms every 10 years. For CO, choose alarms that meet UL 2034.
Where smoke alarms go
- Inside each bedroom and outside every sleeping area.[1]
- On every level of the home, including the basement.[1]
- On the ceiling, or high on a wall following the manufacturer's instructions; CPSC describes the center of the ceiling or 6 to 12 inches below it on a wall.[1,2]
- Away from the stove: if cooking sets an alarm off, USFA suggests moving it several feet farther from the kitchen.[1]
Ionization vs. photoelectric: why you want both
Ionization alarms tend to respond faster to flaming fires, while photoelectric alarms tend to respond faster to smoldering fires. Because you cannot predict which kind of fire you will have, CPSC and the U.S. Fire Administration recommend having both types, or dual-sensor alarms that combine them.[1,2]
Interconnected alarms sound together: smoke in the basement sets off the alarm outside the bedrooms too. That can buy precious escape time.[1,2]
Carbon monoxide alarms
Carbon monoxide has no color or smell. CPSC reports that more than 200 people in the U.S. die each year from CO produced by non-automotive consumer products.[3]
- Install CO alarms on every level of the home and outside sleeping areas.[3]
- Keep them away from heating vents and furniture. CPSC does not recommend placing them in the kitchen or directly above fuel-burning appliances. Follow the manufacturer's placement instructions.[3]
- Buy alarms that meet UL 2034, either battery-operated or plug-in with battery backup.[3]
Upkeep that takes five minutes a month
Alarm plan
- Smoke alarm in every bedroom and outside each sleeping area
- At least one smoke alarm and one CO alarm per level
- Both sensing types, or dual-sensor alarms
- Interconnected where possible
- Test monthly; replace smoke alarms at 10 years
Sources
Every figure in this guide comes from the official sources below. We summarize them in our own words; check the source for the full guidance.
- 1Smoke AlarmsU.S. Fire Administration (FEMA)
- 2Smoke Alarms: Why, Where, and Which? (Publication 559)U.S. Consumer Product Safety Commission
- 3Carbon Monoxide Fact SheetU.S. Consumer Product Safety Commission
- 4CO AlarmsU.S. Consumer Product Safety Commission
This guide is general consumer information, not medical, legal or professional advice. Always follow the manufacturer’s instructions for your product. See our editorial policy and affiliate disclosure.
