What smoke alarm means
A smoke alarm is a self contained device that senses smoke and sounds an alarm. Hardwired alarms are interconnected so one sets them all off.
Where it matters on a home inspection job
Missing or outdated alarms are frequent inspection findings, and remodels often trigger updating them. Know the local rule for locations and interconnection before quoting.
What the model code says
- Smoke alarms go in each sleeping room and outside each separate sleeping area near the bedrooms. (IRC 2021, Chapter 3)
- They also go on each additional story, including basements and habitable attics. (IRC 2021, Chapter 3)
Check which code edition your building department enforces for smoke alarm before you quote.
What it costs
The smoke detector installation cost guide has the typical job at $110 and the usual range at $70 to $150. The guide shows its sources and what moves the price.
Work it out
- Cost guide: Smoke detector installation cost
- Tools, templates and guides: Free home inspection resources
Sources: 2021 International Residential Code, Chapter 3, Building Planning (ICC). Checked October 9, 2026.