Previously, we explored both smoke alarms and carbon monoxide detectors separately.
However, for many households, a combination alarm that detects both smoke and CO is a more convenient and effective solution.
These dual-function devices eliminate the need for multiple units, saving space and simplifying maintenance.
More importantly, they provide comprehensive protection by detecting different types of fire hazards and CO leaks, ensuring a safer home environment.
In this article, we review and compare the top battery-powered combination smoke and CO detectors available in 2024.
| Brand | Model | Battery Life | Display | Size (inches) | Weight (ounces) | Price Range |
| Kidde | 9th Edition | 10 years | No | 5.6 x 5.6 x 1.8 | 7.7 | $45 – $55 |
| Kidde | 6th Edition | 10 years | No | 5.6 x 5.6 x 1.8 | 7.7 | $45 – $55 |
| First Alert | SMCO210 | 10 years | No | 5.9 x 5.9 x 1.8 | 8.2 | $30 – $40 |
| First Alert | SMCO100 | 10 years | No | 5.9 x 5.9 x 1.8 | 8.1 | $30 – $40 |
| X-Sense | SC07 | 10 years | Yes | 5.7 x 5.7 x 2.0 | 8.0 | $30 – $40 |
| X-Sense | SC01 | 10 years | Yes | 5.7 x 5.7 x 2.0 | 8.1 | $30 – $40 |
In-Depth Reviews
All the models reviewed use photoelectric smoke sensors paired with electrochemical CO sensors, which are the industry standard for accurate detection and minimal false alarms.
This ensures that all units provide consistent performance in detecting both smoldering fires and harmful CO exposure.
Kidde 9th Edition: What’s New?
Kidde remains one of the most recognized brands in fire safety, and both models offer robust performance.
Kidde’s 9th Edition is an upgraded version compared to its 8th Edition, with improvements in sensor technology and overall reliability.
One of the key enhancements is a faster response time for smoke detection, reducing false alarms while maintaining accuracy.
Additionally, Kidde has improved battery efficiency, ensuring that the 10-year battery lasts its full lifespan without performance degradation.
Compared to X-Sense, Kidde does not offer an LCD display, but it remains a leading choice for users who prioritize trusted brand reliability and proven sensor accuracy.
First Alert SMCO210 vs. SMCO100
(SMCO210)
(SMCO100)
First Alert’s SMCO210 and SMCO100 models share many similarities, but there are notable differences that may influence purchasing decisions.
The SMCO210 includes enhanced CO detection accuracy, with improved sensitivity to lower concentrations of carbon monoxide, making it a better choice for homes with older heating systems or attached garages.
In contrast, the SMCO100 is a slightly more compact option, designed for easy installation in smaller spaces without compromising detection efficiency.
Another distinction lies in the alarm loudness—while both models meet industry standards, the SMCO210 emits a slightly louder, more piercing alert tone, which could be an important factor for individuals with hearing impairments.
For those prioritizing precise CO detection, the SMCO210 is the better choice. If space efficiency and a more discreet alarm are preferred, the SMCO100 provides solid value at a slightly lower profile.
X-Sense SC07 vs. SC01
(SC07)
(SC01)
X-Sense’s SC07 and SC01 are functionally identical, both featuring a 10-year sealed battery, LCD display for real-time monitoring, and compact design.
While both are reliable options, they are priced competitively within the same range, making them strong choices for those who want an easy-to-read display and dependable performance.
Compared to other brands, X-Sense offers a more modern design with a sleek appearance that integrates well into contemporary home settings.
Comparing Across Brands
- Kidde vs. First Alert: Kidde’s alarms are more advanced with later-generation sensors, whereas First Alert is a more budget-friendly option without sacrificing essential safety features.
- Kidde vs. X-Sense: X-Sense provides a modern design and LCD display, while Kidde offers proven reliability and brand recognition.
- First Alert vs. X-Sense: X-Sense wins in terms of design and ease of monitoring, while First Alert is a practical choice for those seeking a no-frills, cost-effective device.
Final Thoughts: Which One Should You Buy?
Choosing the right combination smoke and CO alarm depends on your priorities:
- If you want a display, the X-Sense SC07 or SC01 are excellent choices.
- If you prefer Kidde’s trusted reputation, the 9th Edition is the best pick for an upgraded model.
- For a budget-friendly option, First Alert’s SMCO210 or SMCO100 deliver great value.
- If reliability and brand recognition matter most, Kidde remains the strongest option overall.
Regardless of which model you choose, ensure proper installation and regular testing to maintain optimal safety.
A well-placed and functional smoke and CO alarm is a vital investment in your home’s security.