Where to Install Smoke Alarms

Every bedroom, every hallway outside the bedrooms, every level.

A smoke alarm only helps if it can sense smoke early and you can hear it. Here is where the NFPA and fire marshals across the country say they belong.

The rooms that need one

  • Inside every bedroom.
  • Outside each sleeping area, usually the hallway that leads to the bedrooms.
  • On every level of the home, including the basement. In the basement, put it on the ceiling near the bottom of the stairs.

Bigger homes may need more than that. Long hallways, open floor plans and rooms far from the bedrooms all deserve a closer look. Interconnecting the alarms means that when one goes off, they all go off.

How high to mount it

Smoke rises, so alarms go on the ceiling or high on a wall.

  • Ceiling mount: keep the alarm at least 4 inches from the wall.
  • Wall mount: the top of the alarm should be no more than 12 inches below the ceiling.
  • Peaked or cathedral ceilings: mount it within 3 feet of the peak, but not in the very top point, where a pocket of trapped air can keep smoke away. About 4 inches down from the peak works.

Places to avoid

  • Within 10 feet of the stove. Cooking smoke is the top cause of nuisance alarms. Near the kitchen, use a photoelectric alarm or one listed as cooking-resistant. Here is why.
  • Bathrooms with a shower, and right outside their doors. Steam can set alarms off.
  • Next to windows, doors, heating and cooling vents or ceiling fans. Drafts can blow smoke away from the sensor.
  • Garages, furnace rooms and unheated attics. Exhaust, dust and temperature swings cause problems. Ask about heat alarms for those spaces.

Follow the instructions in the box. Every manufacturer includes placement guidance for its model, and your city or state may have its own code requirements. If you are replacing hardwired alarms, the wiring has to be done safely. When in doubt, hire a licensed electrician.

A quick home checklist

  1. Sketch your floor plan. Mark every bedroom, each hallway outside the bedrooms and each level.
  2. Walk the house with the sketch. Check off every alarm you find and note the date printed on it.
  3. Fill the gaps. Add alarms where your sketch has none and replace anything 10 years or older.
  4. Test them all. Use the monthly test to confirm each one sounds.