Detector Replacement
$75–$125 per detector
- Removal of old detector
- Installation of new hardwired detector
- Battery backup included
- Interconnect wiring verified
- Test all connected detectors
Replace existing hardwired detectors
Residential · Safety
Smoke & Carbon Monoxide Detectors in St. Charles & St. Louis County
Hardwired smoke and CO detector installation for complete home safety. Interconnected systems for whole-home protection throughout St. Louis and St. Charles County.
MO License #20250016884.9 Star Average. 410+ Reviews.In Business Since 2010Cottleville, MO
Is This You?
Signs You Need This
- Smoke detectors over 10 years old
- Smoke detectors lose sensitivity with age. The manufacture date is on the back. Replace any detector over 10 years old.
- Detectors chirp despite new batteries
- Chirping with fresh batteries indicates end-of-life. The detector's sensor has degraded and needs replacement.
- Only battery-powered detectors
- Battery-only detectors aren't interconnected: one can alarm while others stay silent. Hardwired systems wake the whole house.
- No detector in every bedroom
- Current code requires smoke detectors inside each sleeping room, not just in hallways. Many older homes don't comply.
- No carbon monoxide detectors
- CO is odorless and lethal. Any home with gas appliances, attached garage, or fireplace needs CO detectors near bedrooms.
- Detectors painted over
- Paint clogs smoke sensors, making them ineffective. Painted detectors must be replaced.
- Missing detectors in basement
- Basements often contain furnaces and water heaters, both fire and CO sources. Code requires detectors on every level.
- Frequent false alarms
- If detectors false alarm from cooking or steam, they may be wrong type or location. We'll relocate or replace with appropriate types.
Pricing
What It Costs
An estimate, not a quote. Estimates for installs and upgrades are free; your exact flat price comes after we see the job, and it's the price you pay.
Whole-Home System (4-8 Detectors)
$500–$1,000
- Smoke detectors in all required locations
- CO detectors near sleeping areas
- Hardwired with battery backup
- All units interconnected
- Heat detector for kitchen
- Complete system testing
Standard 3-4 bedroom home
Smart Detector System
$800–$1,500
- Nest Protect or equivalent smart detectors
- Phone alerts and voice warnings
- Self-testing with app notifications
- Professional installation
- App setup and training
- Integration with existing hardwired (where possible)
Modern connected home protection
How It Works
From First Visit to Final Inspection
Typical job: 2-4 hours.
Code Compliance Assessment
We evaluate your current detector setup against code requirements: smoke detectors inside each bedroom, outside sleeping areas on each level, and on every floor including basement. We also assess CO detector requirements based on fuel-burning appliances.
Location Planning
For new installations, we identify optimal mounting locations, typically ceiling-mounted, away from corners, HVAC vents, and windows. For kitchens, we plan heat detector placement instead of smoke detectors to reduce false alarms.
Quote & Scheduling
You receive a quote covering all detectors, interconnect wiring, and labor. For simple replacements of existing hardwired detectors, we can often complete the work during the same visit.
Power Off & Preparation
We turn off power to the existing detector circuit at the breaker. For new installations, we identify the best circuit to tap for power and plan the interconnect wire routing.
Wiring Installation
For new or expanded systems, we run the power and interconnect wiring through attic space or wall cavities to each detector location. All detectors must be interconnected so when one alarms, they all alarm.
Detector Mounting
We install mounting brackets, connect power and interconnect wiring to each detector, and secure the detectors in place. We install fresh backup batteries in every unit.
System Testing
We test each detector individually using the test button, then verify the interconnection works: pressing test on one detector should trigger all connected detectors to alarm. We document the test for your records.
Verified Reviews
Read all reviews What Homeowners Say About Our Work
Reviews that mention this work first.
Thea B.
bbb
06/20/2025
Monte M.
04/19/2025
Linda S.
angi
05/2017
4.9 Star Average. 410+ Reviews. Google, Facebook, BBB and Angi.
Fully licensed and insured in Missouri:MO State License #2025001688,St. Charles County #E25-000008,St. Louis County #ES4501.Lifetime workmanship warranty on installed work.
Service area + officeMon-Fri · 8:00 AM - 4:00 PM
Licensed Electricians Across St. Charles & St. Louis Counties
Flat-rate pricing before work begins, from an office in Cottleville.
First Choice Electric
5377 State Route N. Suite 437, Cottleville, MO 63304
Mon-Fri 8:00 AM - 4:00 PM
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FAQ
Questions About Smoke & Carbon Monoxide Detectors
How many smoke detectors do I need?
Code requires detectors in each bedroom, outside sleeping areas, and on each level including basement. We'll ensure proper coverage.
What's the benefit of hardwired vs. battery?
Hardwired detectors are interconnected, so all alarms sound when one detects smoke. They're more reliable and meet newer code requirements.
Do I need carbon monoxide detectors?
Yes. Missouri requires CO detectors near sleeping areas in homes with fuel-burning appliances or attached garages.
How often should smoke detectors be replaced?
Smoke detectors should be replaced every 10 years, CO detectors every 5-7 years. The manufacture date is printed on the unit.
Can you add detectors to my existing hardwired system?
Usually yes. We can add compatible detectors to expand your existing interconnected system.
What about smart smoke detectors like Nest?
We install Nest Protect and similar smart detectors. They provide phone alerts, voice warnings, and can interconnect wirelessly with existing detectors.
Should I use ionization or photoelectric detectors?
Photoelectric detectors respond faster to smoldering fires, ionization to flaming fires. We recommend dual-sensor models for best protection.
Do I need a heat detector in my kitchen?
Yes. Heat detectors replace smoke detectors in kitchens to reduce false alarms while still providing fire protection.
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Get Your Flat Price for Smoke & Carbon Monoxide Detectors
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