Continuing our exploration of home fire safety, we now turn to wired smoke alarms. Unlike battery-powered models, wired smoke alarms connect directly to a home’s electrical system, ensuring continuous operation without worrying about battery life.
Most models also feature battery backups to maintain functionality during power outages.
In this review, we compare some of the best wired smoke alarms on the market, providing insights into their features, strengths, and ideal use cases.
Understanding Wired Smoke Alarm Technology
Wired smoke alarms share the same fundamental sensor technology as battery-powered models, with two main types:
- Photoelectric Sensors (Recommended): These alarms excel at detecting slow-burning, smoldering fires, such as those caused by electrical faults or unattended cigarettes. They are less prone to false alarms from cooking fumes, making them ideal for placement near kitchens and living spaces.
- Ionization Sensors: These alarms respond more quickly to fast-flaming fires, such as those ignited by paper, grease, or gasoline. However, they tend to be more sensitive to non-threatening smoke, increasing the likelihood of false alarms near kitchens or bathrooms.
Most wired smoke alarms also offer an interconnectivity feature, allowing multiple alarms to trigger simultaneously when smoke is detected in any area of the home. This significantly enhances safety in larger residences.
Why Are Most Wired Smoke Alarms Ionization-Based?
Many wired smoke alarms use ionization sensors primarily due to legacy system compatibility and cost-effectiveness.
Older interconnected alarm systems were largely built around ionization technology, making manufacturers continue to produce compatible models.
Additionally, ionization sensors are generally cheaper to manufacture, making them more cost-effective for widespread adoption. However, modern fire safety recommendations increasingly favor photoelectric sensors due to their superior performance in detecting smoldering fires and reducing false alarms.
| Brand | Model | Price Range | Sensor Type | Backup Battery | Interconnect Capability |
| First Alert | SMI100-AC | $25-$35 | Ionization | 9V Battery | Yes |
| First Alert | 9120B | $30-$40 | Ionization | 9V Battery | Yes |
| First Alert | SMI105-AC | $35-$45 | Ionization | 10-Year Battery | Yes |
| Kidde | i12040 | $20-$30 | Ionization | 9V Battery | Yes |
| Kidde | i4618AC | $30-$40 | Ionization | 9V Battery | Yes |
| Kidde | 20SA10 | $40-$55 | Photoelectric | 10-Year Battery | Yes |
Choosing the Right Wired Smoke Alarm: Key Differences
Kidde 20SA10: The Best Overall Choice
Among all the wired smoke alarms reviewed, Kidde 20SA10 stands out as the best option. It features photoelectric sensor technology, which provides superior detection of slow-burning fires while minimizing false alarms from cooking smoke.
Additionally, its sealed 10-year battery backup ensures uninterrupted protection, eliminating the need for frequent battery replacements.
The only downside to Kidde 20SA10 is its higher price point, but for homeowners prioritizing safety, reliability, and long-term convenience, it remains the top recommendation.
Ionization vs. Photoelectric: The Core Consideration
If you are looking for an alarm with quicker response times to fast-flaming fires, ionization-based models like First Alert SMI100-AC and Kidde i12040 provide excellent protection.
However, if you prefer an alarm that minimizes false alarms from cooking smoke and is better suited for detecting slow-burning fires, photoelectric models like Kidde 20SA10 are a better choice.
(First Alert SMI100-AC)
(Kidde i12040)
Battery Backup: 9V vs. 10-Year Lithium
Most traditional wired smoke alarms, such as First Alert 9120B and Kidde i4618AC, use 9V backup batteries, which require periodic replacement.
For those seeking a long-term maintenance-free option, First Alert SMI105-AC and Kidde 20SA10 include sealed 10-year lithium batteries, ensuring continuous protection without the hassle of changing batteries.
(First Alert 9120B)
Interconnectivity and Expanded Safety
All the models in this review offer interconnect capabilities, allowing multiple alarms to trigger simultaneously when one detects smoke.
This feature is particularly useful for larger homes or multi-story residences. If you’re looking for a cost-effective interconnected system, Kidde i12040 and First Alert 9120B offer solid choices, whereas those prioritizing extended battery life should consider First Alert SMI105-AC and Kidde 20SA10.
Installation Guide for Wired Smoke Alarms
nstalling a wired smoke alarm requires a basic understanding of electrical wiring. If you are not comfortable working with electricity, it is best to hire a qualified electrician. Follow these steps to install a wired smoke alarm safely:
- Turn Off Power – Before starting, switch off power to the circuit at your home’s breaker panel to prevent electrical hazards.
- Choose the Installation Location – Mount alarms on ceilings or high on walls, following the manufacturer’s recommended placement for optimal detection.
- Remove the Old Alarm (If Replacing) – If you are upgrading from an older model, carefully disconnect the wiring harness and remove the mounting bracket.
- Connect the Wires – Match the corresponding wires: black (hot), white (neutral), and yellow/orange (interconnect, if applicable). Use wire nuts to secure the connections.
- Attach the Alarm to the Mounting Bracket – Secure the alarm in place and ensure it is properly aligned.
- Restore Power and Test – Turn the breaker back on and press the test button to verify functionality. Ensure interconnected units trigger simultaneously.
Additional Tips:
- Avoid placing alarms near air vents, windows, or ceiling fans, as this can interfere with smoke detection.
- If installing multiple alarms, make sure they are properly interconnected for maximum protection.
- Regularly test and maintain alarms by checking batteries (if applicable) and cleaning dust buildup.
Final Thoughts
Wired smoke alarms provide an added layer of reliability by connecting directly to a home’s electrical system while still offering battery backup. Among the brands, Kidde and First Alert remain industry leaders due to their affordability, reliability, and widespread availability.
For those looking for a traditional wired smoke alarm with reliable performance, First Alert 9120B and Kidde i4618AC are strong options. If you prefer long-term maintenance-free operation, First Alert SMI105-AC and Kidde 20SA10 provide extended battery life and robust performance.
For those who want the best overall wired smoke alarm, Kidde 20SA10 is the top recommendation despite its higher price. It delivers the best combination of detection technology, battery backup, and reliability for long-term home safety.
No matter which wired smoke alarm you choose, ensuring proper placement and regular maintenance is key to maximizing fire safety in your home.
Stay safe, and choose wisely🏠