Best Smoke and Carbon Monoxide Detector: A Complete Buyer’s Guide for 2025

Safety starts at home, and the best smoke and carbon monoxide detector is your first line of defense against fire and deadly gas leaks. A reliable combination smoke and CO detector provides peace of mind by detecting smoke and carbon monoxide (CO) early, alerting you before it becomes life-threatening.

With smart features, battery backup, and interconnected capabilities, modern detectors are more effective than ever. In this comprehensive guide, we will explore the top-rated smoke and carbon monoxide detectors, their features, types, brands, prices, and how to choose the right one for your home, RV, garage, or commercial space.

Why You Need the Best Smoke and Carbon Monoxide Detector

• Fire safety: Detects smoke from fires quickly.
• CO protection: Carbon monoxide is odorless, colorless, and lethal.
• Interconnected alerts: All alarms sound if one detects danger.
• Smart notifications: Mobile app alerts if you’re away from home.
• Peace of mind: 24/7 monitoring for your family and property.

Types of Smoke and CO Detectors

Top Brands of Smoke and Carbon Monoxide Detectors

• First Alert smoke and CO detector
• Kidde smoke and CO detector
• Nest (Google)
• X-Sense
• Honeywell

Top 10 Best Smoke and Carbon Monoxide Detectors (2025)

Key Features to Look For

• Smoke and carbon monoxide detector with voice alerts
• Smoke and CO detector with mobile app control
• Smoke and carbon monoxide alarm with battery backup
• Interconnected smoke and CO detectors for multi-room safety
• Smart smoke and carbon monoxide alarm compatible with Alexa and Google Home
• Hardwired smoke and carbon monoxide detector with battery backup
• Portable smoke and CO detector for travel, RV, and garage safety
• Digital display smoke and carbon monoxide detector with real-time ppm CO readings

Best Detectors for Different Needs

CO and Smoke Detection Technology Explained

Modern detectors combine photoelectric smoke sensors for smoldering fires and electrochemical CO sensors for accurate carbon monoxide detection. Features like digital ppm readings for carbon monoxide, mobile alerts, and interconnected alarms enhance safety.

Detector Lifespan and Maintenance

• Average lifespan: 7-10 years
• Test monthly
• Replace batteries annually (unless sealed 10-year models)
• Clean with a vacuum or soft brush twice a year
• Replace the detector at the end of its service life (check the label)

Reviews of some of the top-rated and best smoke and carbon monoxide detectors

Here’s the detail

Google Nest Protect (2nd Gen) – Best Smart Smoke and CO Detector

Rating: ⭐⭐⭐⭐⭐ (4.8/5)
Price: $119 – $129

Key Features:

• Smart smoke and CO detector with Wi-Fi and app alerts
• Split-Spectrum Sensor (detects both fast-burning and smoldering fires)
• Voice alerts with location (e.g., “Smoke in the kitchen”)
• Self-testing and battery status notifications via the Nest app
• Works with Google Home, Alexa via routines

Pros:

• Premium build quality and reliability
• Mobile notifications even when away
• Voice alerts reduce panic
• Color-coded LED ring for status
• Long battery life (5-10 years)

Cons:

• Price is higher than standard models
• Requires Wi-Fi for smart features

Best For:

Smart homes, tech-savvy users, large houses.

First Alert Onelink Safe & Sound – Best for Smart Homes with Alexa

Rating: ⭐⭐⭐⭐ (4.5/5)
Price: $199 – $219

Key Features:

• Smoke and CO detector with Alexa built-in
• Premium speaker with AirPlay 2 for music and alerts
• App control with mobile alerts
• Voice location alerts

Pros:

• Doubles as a smart speaker
• Compatible with Apple HomeKit and Alexa
• Easy to install
• Accurate smoke and CO detection

Cons:

• Expensive
• No Google Home support
• Larger than standard detectors

Best For:

Smart home enthusiasts wanting built-in Alexa.

Kidde Smoke & Carbon Monoxide Detector (Model: 21026065) – Best Budget Pick

Rating: ⭐⭐⭐⭐ (4.3/5)
Price: $45 – $65

Key Features:

• Battery-operated
• Voice alerts for smoke or carbon monoxide
• LED indicators
• Test/Hush button

Pros:

• Affordable
• Reliable detection
• Easy to install with no wiring
• Voice distinction for smoke or CO events

Cons:

• No smart features
• Battery needs manual replacement

Best For:

Budget-conscious users, renters, small homes.

First Alert SCO7CN – Best Battery-Powered Detector

Rating: ⭐⭐⭐⭐ (4.5/5)
Price: $50 – $70

Key Features:

• Battery-operated smoke and CO detector
• Voice alerts specify “Fire” or “Carbon Monoxide”
• Photoelectric sensor (for smoke) and electrochemical sensor (for CO)

Pros:

• Reliable dual-sensor technology
• Clear voice alerts reduce confusion
• Simple installation
• Affordable price

Cons:

• Not interconnected
• No smart app or Wi-Fi features

Best For:

Apartments, condos, and renters.

X-Sense SC01 – Best for Large Homes

Rating: ⭐⭐⭐⭐ (4.6/5)
Price: $65 – $85

Key Features:

• Wireless interconnected smoke and CO detector (connects up to 24 units)
• LCD display shows CO levels in real time
• 10-year sealed lithium battery
• Photoelectric smoke sensor + Electrochemical CO sensor

Pros:

• Real-time digital display
• Long battery life (no battery changes needed)
• Easy wireless interconnection
• Great for large or multi-story homes

Cons:

• No app control or smart features
• Initial setup requires syncing devices

Best For:

Large homes, multi-room setups.

First Alert BRK SC7010BV – Best Hardwired with Battery Backup

Rating: ⭐⭐⭐⭐ (4.4/5)
Price: $65 – $80

Key Features:

• Hardwired with 9V battery backup
• Voice alerts specify the type and location
• Interconnectable with other BRK/First Alert detectors

Pros:

• Very reliable, no battery worries unless backup kicks in
• Voice and alarm alerts
• Good for long-term installations

Cons:

• Installation requires wiring
• No smart features

Best For:

Permanent homes, renovations, new builds.

Kidde KN-COSM-IBA – Best for Interconnected Systems

Rating: ⭐⭐⭐⭐ (4.3/5)
Price: $60 – $75

Key Features:

• Hardwired with battery backup
• Interconnects with up to 24 Kidde devices
• Voice alert and LED status

Pros:

• Reliable interconnected alarms
• Voice alerts reduce confusion
• Backup battery for power outages

Cons:

• Not smart/home compatible
• Wired installation

Best For:

Whole-home protection, especially during renovations.

Conclusion – Which One is Best?

Expert Recommendation:

• For smart features and best performance, go with Nest Protect.
• For budget-friendly yet reliable protection, choose Kidde 21026065.
• For hardwired, interconnected setups, First Alert BRK SC7010BV is solid.
• For large homes, the X-Sense SC01 offers excellent wireless connectivity.

Smoke and CO Detector Battery Replacement Tips

• Replace batteries at least once a year (unless it’s a 10-year sealed battery).
• Replace when the detector chirps (low-battery alert).
• Test detectors monthly after battery replacement.
• Use high-quality alkaline batteries (e.g., Energizer, Duracell).
• For 10-year sealed units, replace the entire detector after the end of life.
• Clean battery contacts with a dry cloth when changing batteries.
• Keep spare batteries on hand for emergencies.

Where to Install Smoke and Carbon Monoxide Detectors in a Home

Smoke Detector Placement:

• Inside every bedroom.
• Outside each sleeping area (like hallways).
• On every level of the home, including the basement.
• In rooms with fire hazards: kitchen (but 10 ft away from stove), laundry room, furnace room.
• Ceiling-mounted for best detection (at least 4 inches from walls).

CO Detector Placement:

• Outside sleeping areas.
• On every floor (including the basement).
• Near fuel-burning appliances (furnaces, fireplaces, water heaters).
• Near or inside attached garages.
• Mounted at knee height (CO mixes evenly but tends to rise with warm air).

How Smoke and CO Detectors Work Together

• A combination detector has two sensors:
  • Photoelectric or ionization sensor for smoke detection.
  • Electrochemical sensor for carbon monoxide.
• The alarm distinguishes between:
  • Smoke/fire alert: Loud alarm + voice (“Fire detected”).
  • CO alert: Loud alarm + voice (“Carbon monoxide detected”).
• Smart detectors send alerts to your smartphone, providing real-time updates whether you’re home or away.
• Some models interconnect, so when one detects danger, all alarms sound simultaneously.

Smoke and CO Detector Maintenance Checklist

Smart Wireless Interconnected Smoke and CO Detectors for Large Homes

Top Picks:

• X-Sense SC01/SC07: Connect up to 24 units, wireless, LCD display.
• Google Nest Protect: Wi-Fi connected, mobile alerts, smart home integration.
• First Alert Onelink: Alexa built-in, app alerts, premium design.

Benefits:

• When one detects danger, all alarms sound.
• App notifications provide real-time alerts.
• Ideal for multi-story homes, large layouts, or detached garages.

Best Commercial-Grade Smoke and CO Detector for Offices & Warehouses

• First Alert BRK SC7010BV: Hardwired, interconnected, with voice alerts.
• Kidde KN-COSM-IBA: Hardwired with battery backup, scalable.
• System Sensor CO1224T + Smoke Detectors: For large-scale commercial installations with control panels.

Features for Commercial Use:

• Hardwired with battery backup
• Interconnectable
• Meets UL 2034 (CO) and UL 217 (Smoke) standards
• Loud alarms (85 dB or more)
• Visual indicators (LED status)

Smoke and CO Detector with Real-Time Air Quality Monitoring

• Google Nest Protect: Monitors smoke, CO, and self-tests sensors.
• Airthings View Plus (CO + Air Quality): Combines CO detection with radon, PM2.5, humidity, VOCs, and more (works alongside smoke detectors).
• X-Sense SC07-W: CO ppm levels display on LCD.

Ideal For:

Homeowners concerned about overall air quality, not just emergencies.

Easy-to-Install Smoke and CO Detector for Renters

• Kidde Battery-Operated Combination Detector (21026065): No wiring, affordable.
• First Alert SCO7CN: Battery-powered with voice alerts.
• X-Sense SC01: Wireless, 10-year sealed battery.

Benefits for Renters:

• No drilling or wiring needed.
• Easy to relocate when moving.
• Long-life sealed battery options reduce maintenance.

Best-Rated Detector for Furnace, Kitchen, Garage, or Basement Safety

• Furnace/Basement:
  First Alert BRK SC7010BV (Hardwired + Backup)
  X-Sense SC01 (Battery with CO display)
• Garage:
  Kidde KN-COB-B-LPM: CO only, specifically recommended for garages.
  Nest Protect: Monitors both smoke and CO with smart alerts.
• Kitchen:
  Google Nest Protect: Smart false alarm reduction near kitchens.
  First Alert SCO7CN: Voice alerts; keep it at least 10 feet from cooking appliances.

Conclusion:

• For large homes: Choose smart, wireless interconnected detectors like X-Sense SC01 or Nest Protect.
• For commercial spaces: Use hardwired detectors like First Alert BRK SC7010BV or System Sensor.
• For renters: Go with battery-powered, easy-to-install models like Kidde 21026065 or First Alert SCO7CN.
• For specialized areas: Use targeted detectors with high reliability for garages, basements, or kitchens.

Battery-Powered Smoke and CO Detector with Digital Display

Recommended Model: X-Sense SC07-W

Features:

• Digital LCD shows real-time CO levels (ppm)
• Photoelectric smoke sensor + electrochemical CO sensor
• Battery-powered with a 10-year sealed lithium battery
• Loud 85dB alarm

• Pros:
  • Easy to install (no wiring)
  • Clear digital readout for CO
  • Long battery life
  • Reliable dual-sensor technology
• Cons:
  • No smart features or app connectivity
• Best For:
  Homes, apartments, renters needing visibility of CO levels.

Combination Smoke and Carbon Monoxide Detector with Voice Alerts

Recommended Model: First Alert SCO7CN

• Features:
  • Voice alert distinguishes “Fire” or “Carbon Monoxide”
  • Photoelectric (smoke) + Electrochemical (CO) sensors
  • Battery-powered
  • Test/Silence button
• Pros:
  • Clear voice announcements reduce confusion
  • Affordable
  • No wiring required
  • Compact design
• Cons:
  • No digital display
  • Not interconnected
• Best For:
  Bedrooms, hallways, living spaces.

Hardwired Smoke and CO Detector with Backup Battery

Recommended Model: First Alert BRK SC7010BV

• Features:
  • Hardwired with 9V battery backup
  • Photoelectric smoke sensor + Electrochemical CO sensor
  • Voice alerts specify type and location
  • Interconnectable with other BRK/First Alert devices
• Pros:
  • Continuous power with battery backup
  • Voice and alarm alerts
  • Reduced false alarms
  • Meets building code requirements
• Cons:
  • Requires electrical wiring for installation
  • No smart features
• Best For:
  Permanent homes, offices, and new builds.

Affordable Smoke and Carbon Monoxide Detectors with Long Battery Life

Recommended Model: Kidde 21026065

• Features:
  • Combination smoke and CO alarm
  • Voice alerts
  • 9V battery-powered
  • LED indicators for smoke/CO
• Pros:
  • Very affordable
  • Long battery life (1 year standard, or opt for lithium)
  • Easy wall/ceiling mount
  • Simple operation
• Cons:
  • No digital display
  • No interconnected features
• Best For:
  Budget-conscious homeowners, renters.

Best Smoke and CO Detector Compatible with Alexa and Google Home

Recommended Model: Google Nest Protect (2nd Gen)

• Features:
  • Works with Google Home; routines via Alexa
  • Mobile notifications, voice alerts, and self-tests
  • Split-spectrum smoke sensor + electrochemical CO sensor
  • App control with history, testing, and battery status Pros:
  • Industry-leading smart features
  • Beautiful design with LED status ring
  • Reliable and accurate
  • Works with smart home ecosystems
• Cons:
  • Higher price point
  • Requires Wi-Fi for smart features
• Best For:
  Smart homes, families, tech enthusiasts.

Smoke and CO Detector with App Notifications and Remote Monitoring

Recommended Model: First Alert Onelink Safe & Sound

• Features:
  • App notifications for smoke and CO alerts
  • Built-in Alexa speaker and AirPlay 2 compatibility
  • Voice alerts with location
  • High-end sound system plus alarm
• Pros:
  • Excellent for smart homes
  • Combines safety with entertainment (speaker)
  • Real-time notifications anywhere
• Cons:
  • Expensive
  • Bulky compared to basic detectors
  • Google Home not directly supported
• Best For:
  Smart homes, large households, users who want integrated alarms + entertainment.

Portable Dual-Sensor Smoke and CO Detector for RV or Travel

Recommended Model: Kidde KN-COEG-3

• Features:
  • Portable, plug-in CO and explosive gas detector
  • Battery backup included
  • Detects CO, propane, and natural gas
  • Loud 85dB alarm
• Pros:
  • Compact and portable
  • Great for RVs, motorhomes, or travel
  • Multiple gas detection (CO + explosive gases)
• Cons:
  • Plug-in required (120V), but has battery backup
  • Not a smoke detector — pair it with a portable smoke alarm

For True Portable Dual Smoke & CO:

Combine with First Alert SCO5CN (battery-powered smoke + CO).

• Best For:
  RVs, travel trailers, camping cabins, tiny homes.

Frequently Asked Questions (FAQs)

What is the best smoke and carbon monoxide detector for home use?

Google Nest Protect and First Alert Onelink Safe & Sound are top choices for smart features and reliability.

What’s better: battery-powered or hardwired smoke and CO detectors?

Hardwired detectors with battery backup are more reliable for permanent installations, while battery-powered models are portable and easier to install.

Do smart detectors work with Alexa or Google Home?

Yes. Models like Nest Protect and First Alert Onelink are Alexa-compatible and work with Google Home for voice commands and alerts.

How often should I replace smoke and CO detectors?

Most detectors should be replaced every 7-10 years, depending on the manufacturer.

Can I use the same detector for smoke and carbon monoxide?

Yes, a combination smoke and CO detector handles both threats effectively.

Which is the best wireless interconnected smoke and CO detector?

X-Sense SC07-W is a top-rated wireless interconnected smoke and CO detector with 10-year battery life.

Are there detectors suitable for RVs or garages?

Yes, portable smoke and CO detectors like those from Kidde or X-Sense are designed for RVs and garages.

Do detectors show real-time CO levels?

Some models, like digital display smoke and CO detectors, show ppm readings for carbon monoxide.

What is the best affordable smoke and CO detector?

Kidde KN-COSM-BA offers a balance of affordability and reliability.

Are energy-efficient smoke and CO detectors available?

Yes. Nest Protect and First Alert Interconnected detectors are known for long battery life and energy efficiency.

Summary

Choosing the best smoke and carbon monoxide detector is crucial for safety. Whether you prefer a battery-powered, hardwired, or smart smoke and CO detector, ensure it meets your home’s needs. Features like voice alerts, app control, digital displays, and interconnectivity offer enhanced protection.

Brands like First Alert, Kidde, and Nest lead the market with reliable and smart models. Whether it’s for your house, RV, garage, or commercial building, investing in the right detector can save lives.

Conclusion

A smoke and carbon monoxide alarm with battery backup and smart features is no longer a luxury—it’s a necessity. Prioritize models with voice alerts, mobile app integration, and interconnected systems. Whether you’re looking for the best wired, wireless, portable, or plug-in smoke and CO detector, this guide provides everything you need to make an informed decision.