DIWired power, dependable backup
Hardwired Smoke Detector Replacement
Hardwired alarms use household power and a backup source for outages. Replacing one requires attention to the existing interconnect, connector, age of companion units and the manufacturer’s compatibility requirements.
Why backup power still matters
A fire does not wait for utility power to return. The First Alert SM105-AC used by Detector Inspectors is hardwired and includes a sealed 10-year backup. That removes annual backup-battery changes for the replacement unit while preserving protection during outages.
Interconnection is part of the system
When compatible alarms are interconnected, one alarm can sound the others. That matters when smoke begins far from a sleeping area. The replacement should preserve the intended warning chain rather than treating every ceiling unit as isolated.
Price and next step
Detector Inspectors publishes $65 per hardwired smoke alarm replacement, including the specified unit, parts and labor. Call with the number of alarms and any model information you can safely read; do not climb if access is unsafe.
Safety references
Primary sources used for this page:
Manufacturer instructions and current local requirements control. For an emergency, call 911.