HH Homeowner's Handbook
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TASK NO. 097 Upgrade

Install smart smoke/CO detectors

Upgrades & Smart Home
Trigger
Upgrade for interconnected alerts
Who does it
DIY or Pro
Est. time
1-2 hrs per unit
Est. cost
$40-120 per unit
Difficulty
●●●○○
Step by step
  1. Plan detector locations: every bedroom, hallway, and level of the home.

  2. Turn off power at the breaker if hardwiring; verify with a tester.

  3. Mount the new base plate and connect the wiring harness/pigtail.

  4. Pair each unit with the manufacturer's app and assign it to a room.

  5. Test all units and set up mobile alerts.

Questions to ask your pro
  • Are you a licensed electrician for hardwired installations?
  • Will all detectors be hardwired and interconnected so every unit sounds when one triggers?
  • Are these units compatible with my existing alarm wiring?
  • Do they meet current building code requirements for placement and quantity in my jurisdiction?
  • Do they include both smoke and carbon monoxide detection in one unit?
  • What is the battery backup duration in a power outage?
  • What is the useful lifespan and when will I need to replace the sensors?
Video guide
How to Install Smart Smoke and CO Detectors - This Old House
Watch this guide
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