Solved! Where to Place the Smoke Detectors in Your House

Install life-saving smoke detectors in the right locations throughout your home and ensure they’re all up to code.

Where to Put Smoke Detectors, Solved!


Q: We’re building a large addition on our house—to include two bedrooms, a vaulted great room, and two additional bathrooms. So, where do we put smoke detectors for the greatest fire safety?

A: Kudos to you for thinking about this small yet crucial detail! There are guidelines for the placement of smoke detectors you should keep in mind. In fact, while your current ones may be in the appropriate locations, you may need to upgrade the devices in the older parts of the house at the same time that you install new ones in the addition. International Building Code (IBC), a comprehensive compilation of safe building guidelines, includes a requirement to upgrade an entire home’s smoke detection system at the same time any major remodeling occurs, such as the large addition you’re building.

First, to meet code, know that smoke detectors must be connected to one another and wired to the home’s electrical system. This is called an “interconnected” system, and if one smoke detector goes off, all of them will, alerting folks throughout the house. The battery-operated smoke detectors already in your home will probably need to be replaced by an interconnected system.

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Call your local building authority to find out if your community has adopted IBC’s smoke detector rules. Fortunately, the guidelines as to where to put smoke detectors are simple, so keep reading to learn how many you’ll need and where to place them to protect your family.


Where to Put Smoke Detectors, Solved!


Install detectors on or as near to the ceiling as possible.

Many smoke detectors are designed to mount to a ceiling, but some can also be wall-mounted when attaching to a ceiling isn’t feasible, such as when it would be impossible to retrofit the wires necessary for connecting them. In this case, smoke detectors should be within a few inches of the ceiling. IBC requires a detector be installed within 12 inches of the ceiling, but the nearer, the better.

Install a smoke detector in every sleeping area.

This means every bedroom, sleeping porch, or any other space in your home where someone might sack out (perhaps a cushy window seat?) should have a smoke detector.

A detector should be installed in a hallway if one or more bedroom doors open from the hallway.

Just one detector is necessary for this spot, whether the hallway serves one bedroom or three. The detector should be centrally located between the bedroom doors.

Install a detector in any room that lies on the path between a sleeping area and the closest exterior door.

For example, if a bedroom door opens into a hallway and to get outside from there, you’d have to go through a great room, put a detector in the great room. If the route of escape then passes through the kitchen, a detector should be located in the great room and in the kitchen. Any room you’ll pass through from the bedroom to the exterior door should have a detector.

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Install at least one smoke detector on every level of your home.

While smoke detectors are vital in sleeping areas, you’ll need to put one on every floor, even if that floor has no bedrooms. This includes an unfinished basement.

To prevent false triggering of the smoke detectors, don’t install them too near a stove or a steamy bathroom.

Nothing’s more frustrating than all the detectors in the house going off because someone burned the toast. The IBC recommends positioning smoke detectors a minimum distance away from stoves, ovens, and bathrooms, depending on the type of detector being installed.

  • A photoelectric smoke detector (triggered when smoke or steam blocks a beam of light) should be located no closer than six feet from a cooking appliance, such as a stove or oven, and no closer than three feet from a bathroom door.
  • An ionization smoke detector (smoke enters a chamber and interrupts an electrical current, which triggers the alarm) should be installed no closer than 20 feet from a cooking appliance, and no closer than three feet from a bathroom door. Ionization smoke detectors are sensitive to even tiny amounts of smoke or steam.


Where to Put Smoke Detectors, Solved!


Measure distance horizontally, not vertically.

To ensure that you get the correct minimum setback from a stove or oven, don’t measure from the top of the appliance up the wall. Instead, measure from the outer edge of the stove horizontally, and then install the smoke detector above that point. Heat and smoke both rise, so positioning a detector directly above a stove will lead to numerous false alarms.

Your local building code might require additional smoke detectors.

The IBC serves as the minimum standard for safe construction, but many communities strengthen those codes with rules of their own. If your community has additional codes, in addition to the above guidelines, you may need to install detectors in rooms that have gas or wood-burning fireplaces, in laundry rooms, and other spots. Call your local building authority before installing a smoke detector system, and err on the side of caution—an extra detector is preferable to not enough.