FAQ / Troubleshooting: How to choose a smoke alarm

Your application or local codes will drive what type of alarms to choose. Whether you’re replacing existing alarms or adding in new, follow these simple steps:

Step 1
Determine Primary Application:

Battery Operated

  • Existing Multi-family/single family (no code for wired-in alarms)
  • Replacement of existing battery operated.
  • Interconnected alarms not required

Wired-in

  • Replacement of existing wired-in
  • New construction or remodel (code driven)
  • Need to have interconnected alarms either by choice or required by code.

Wireless

  • Existing Multi-family/single family (no code for wired-in alarms). Exception: Wireless alarms with both wireless and wired-in features.
  • Need interconnected alarms but can’t easily pull wires through existing walls or ceilings.
  • Use to bridge between floors
  • Use to bridge between old and new construction
  • Use to bridge between wired-in and battery operated
  • Generally more expensive per alarm but savings are realized through retrofitting costs savings in time, materials and labor.

Step 2
Determine Battery Type:

Battery Operated

  • Carbon Zinc (standard life) lasts at least 1 year
  • Alkaline (extended life) lasts about 2 years
  • Lithium (long life) lasts 6-10 years
  • Sealed Lithium (true 10 year) lasts at least 10 years

Wired-in

  • AC only: Where codes allow such as some motel/hotel applications. Will not operate without AC power.
  • AC with battery backup: Required by most codes today. Provides alarm function when power is out.

Wireless
Choose either:

  • Battery operated
  • Wired-in with battery backup (bridge unit).

Step 3
Determine Sensor Type:

Battery Operated

  • Ionization: Widely used sensor for many applications, detects small particles produced by flaming fires.
  • Photoelectric: detects large particles produced by smoldering fires. Better for nuisance control around kitchens and baths. Required by code in some areas of country like Massachusetts.

Wired-in

  • Photoelectric or Ionization (see above)

Wireless

  • Photoelectric or Ionization (see above)