Best Smoke & Carbon Monoxide Alarms Under $100 (2026)
We ranked units under $100 by a value score combining detection features (smoke and CO), power/interconnect options, user ratings, and practical controls
Top Picks
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1
First Alert hardwired smoke and CO detector with battery backup
Hardwired smoke and carbon monoxide alarm with battery backup for continuous monitoring and an audible 85 dB siren. Easy replacement for older units; tests and ventilation indicators help verify status
- combines CO and smoke detection
- battery backup for power outages
- indicator lights and loud siren
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2
First Alert combination smoke & carbon monoxide alarm
Combination smoke and carbon monoxide alarm with interconnect and battery backup. Early warning alert and easy plug-in installation. Customers note easy installation and reliable functionality
- Interconnect capability
- Battery backup
- Easy installation
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3
X-Sense 2-in-1 Smoke and Carbon Monoxide Detector Alarm
Dual sensor detector protects against smoke and carbon monoxide with a 10-year battery. One customer notes easy installation and good value
- dual threat protection
- long-life battery
- easy installation
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4
First Alert 2-in-1 smoke & carbon monoxide alarm
2-in-1 smoke and carbon monoxide detector with test and silence button. Battery-powered for easy installation and maintenance. Customers note easy installation but mixed feedback on beeping and nuisance alarms
- 2-in-1 smoke and CO protection
- battery-powered for easy install
- test/silence button for verification
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5
X-Sense wireless interconnected smoke & CO detector (1-pack)
Wireless interconnected smoke and CO detector with LCD display and 10-year battery. Interlocks with other alarms for full home protection; easy installation noted by customers. One reviewer mentioned it comes pre-installed
- 10-year battery
- LCD display
- interconnected alarms
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6
First Alert powered alarm SCO5CN smoke and CO detector
A battery-operated smoke and carbon monoxide detector that provides combined alerting. Customers cite easy installation and good value, with mixed feedback on functionality and battery life
- combined smoke and CO detection
- battery operated
- easy installation
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7
X-Sense combo smoke and carbon monoxide detector XP02-WR
X-Sense combination smoke and carbon monoxide detector with voice location. Provides voice alerts and location cues, plus battery/malfunction voice reminders. 1-pack
- voice location guidance
- voice reminders for status
- wide transmission range
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8
X-Sense 2-in-1 Smoke and CO Detector SC01
Standalone smoke and carbon monoxide detector with a 10-year sealed battery and display. Easy to install; works without wireless interconnection. Customer note: easy setup and reliable battery life
- 10-year life battery
- 2-in-1 smoke and CO detection
- standalone unit with display
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9
X-Sense XP02-AR hardwired smoke and CO detector with voice location
Dual-sensor hardwired detector with voice location alerts for smoke and carbon monoxide. Provides clear spoken warnings and location of danger
- Dual-sensor protection
- Voice location alerts
- Hardwired with battery backup
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10
4-in-1 CO detector & gas leak detector
4-in-1 detector with CO, combustible gas, temperature, and humidity monitoring. Provides quick alerts and clear readings with battery backup for safety at home or on the go. Customers note easy installation and a loud, clear alarm
- 4-in-1 sensing
- battery backup
- compact design