Smoke Detector Installation Cost: Hardwired & Interconnected
Replacing a single hardwired smoke detector runs about $100 – $150 for a one-off visit, but in quantity the per-unit cost drops to $40 – $80 each because the electrician is already on site. A brand-new interconnected hardwired system, wiring runs included, typically costs $400 – $900 for a whole house.
Talk through this project
Describe the job, get matched with a local licensed pro on the line.
(612) 353-8317New installs, replacements & repairs · No obligation
| Scope | Typical range | Notes |
|---|---|---|
| Single hardwired swap (one visit) | $100 – $150 | Service-call minimum dominates the price |
| Per unit, replacing several at once | $40 – $80 | Marginal cost once on site |
| Whole-home detector replacement | $300 – $700 | Swapping 5–8 existing hardwired units |
| New interconnected system | $400 – $900 | Includes running interconnect wiring |
| Combination smoke/CO units | +$15 – $40 per unit | Higher device cost than smoke-only |
| Line item | Typical range | Notes |
|---|---|---|
| Detector unit (smoke only) | $15 – $45 | Hardwired with battery backup |
| Combination smoke/CO unit | $35 – $70 | Required near sleeping areas in many codes |
| Labor, single visit | $80 – $130 | Service-call minimum |
| New wiring run per unit | $100 – $250 | Interconnect cable through walls and ceilings |
Want a real number instead of a range?
Calls are answered around the clock and routed to a licensed electrical pro serving your area.
Call & describe the job
Tell us what you need: a new install, an upgrade, or something that stopped working.
Get matched on the line
You are connected with a local licensed electrical pro who serves your area.
Compare your numbers
Use the ranges on this page to sanity-check the quote before you commit.
Hardwired and interconnected: what code wants
Most modern building codes require hardwired, interconnected smoke alarms with battery backup in new construction and major remodels. Interconnected means that when one alarm senses smoke, all of them sound, so a fire in the basement wakes the bedrooms upstairs. The hardwired part means the units draw 120V power, with a battery only as backup.
The standard placement under current codes is one alarm inside each bedroom, one outside each sleeping area, and one on every level including the basement. Where fuel-burning appliances are present, pair that with the right carbon monoxide detector placement. That is why a typical house has five to eight units, and why whole-home counts drive the budget more than any single device price.
- ·One inside each bedroom
- ·One outside each sleeping area (hallway)
- ·One on every level, including basement and finished attic
- ·Combination smoke/CO units where carbon monoxide rules apply
Why one detector costs more than five do each
Smoke detector pricing is dominated by the service-call minimum. An electrician coming out to replace a single chirping unit charges a visit minimum of $80 – $130 regardless of how little wire and time the one swap takes, so the all-in cost lands around $100 – $150.
Replace all the units in the house on the same visit and the math flips. The travel, setup, and minimum are spread across every unit, so the marginal cost of each additional detector drops to $40 – $80, device included. If your alarms are near or past their 10-year replacement date, doing them all at once is the efficient spend.
Replacement vs a brand-new system
Swapping existing hardwired units is the common job: the wiring and interconnect already exist, so the electrician disconnects each old detector, transfers the wiring harness, and clips in the new one. A whole-home swap of five to eight units runs $300 – $700.
Installing a new interconnected system where none exists is a bigger project because it means running interconnect cable through finished walls and ceilings to tie the alarms together. That fishing and patching work pushes a new system to $400 – $900, more in homes with limited attic or basement access. Where running new wire is impractical, wireless interconnected battery alarms are an alternative, though many jurisdictions still require hardwiring in new and remodeled construction.
The 10-year replacement rule
Smoke alarm sensors degrade over time, and manufacturers and fire authorities recommend replacing the entire unit every 10 years, not just the battery. Many newer units have a manufacture date printed on the back and a built-in end-of-life chirp that signals when the whole detector, not the battery, needs to go.
Because the sensors age together, the units in a house usually reach end of life around the same time. That is the moment to do a whole-home replacement at the $40 – $80 per-unit rate rather than paying the single-visit minimum repeatedly as each one starts chirping or beeping.
Ready to get it handled?
One call, no obligation. Describe the job and compare the quote against the ranges above.