Kidde Firex Smoke Alarm i4618AC Ionization Sensor
Best smoke detector for the price
Smoke detectors are among the most important security devices for your home. You never know when you’ll need them, but when you do, they will literally save your life.
According to the National Fire Protection Association, the winter months are when homes are at higher risk of fire-involved accidents, driven by an influx of candles, holiday decorations and your furnace running nonstop.
The larger your home, the more smoke detectors you will likely need, and the NFPA recommends that you install one on every floor, in each sleeping area, at the top of each stairway and stairway-adjacent ceiling if you’re in a basement. After putting six smoke detectors to the test, we found the top three that we’d recommend if you’re shopping for a new unit, or if you want to replace your old one.
As the name suggests, this Kidde smoke detector is equipped with dual sensors that allow it to efficiently detect either type of fire. It’s no surprise that it had the best performance detecting a slow-smoldering fire, averaging 24.1 seconds after initial exposure to smoke, and similarly, the second-best performance detecting a fast-flaming fire, averaging 17.9 seconds.
This ionization detector is a perfect fit if you’re on a budget and just want to make sure your home has a reliable smoke alarm. Featuring a compact size and easy installation, the Kidde Firex i4618AC is battery powered, but you can also wire it to a 120-volt circuit so that battery life is never an issue.
If you are looking for a high-tech device that you can control and communicate with, the Nest Protect is perfect for the task. It features a single button that has “hush,” “test” and “reset” functionality, and you can hard-wire it to a 120-volt circuit or run it on a battery.
Our smoke detection test chamber lets us test how quickly each model raises an alarm when smoke enters the environment.
How we test smoke detectors
When it comes to detecting smoke, time is of the essence. That is why we designed a test that simulates a real-life emergency.
The first thing to know is that there are two main types of fires that these products are designed for: smoldering fires and flaming fires.
A smoldering (or slow-burning) fire refers to the combustion that occurs at the surface of a solid material. Smoldering fires produce large amounts of thick smoke but can’t sustain a flame. Think of a cigarette slowly burning but never actually bursting into flames.
Smoke detection testing in progress.
A smoldering fire can and will become a flaming fire if proper action is not taken immediately.
Flaming fires are the ones we’re more familiar with, and they usually arise from the ignition of any flammable material, such as a flammable substance, wood, paper, etc. These generally produce less smoke than a smoldering fire but are obviously more destructive.
We built a chamber that houses the smoke detector under test and fed to it the two different types of smoke through a chimney. Then, we timed the quickness of the response. The faster the smoke detectors’ alarm was triggered, the better.
To simulate smoke coming from a smoldering fire, I ignited 300g of charcoal and let it heat up for 10 minutes before feeding the smoke. I wanted to make sure most of the coals were ignited and that the smoke was thick enough to trigger the alarm.
Recreating a flaming fire was easy, just 30g of shredded paper did the trick. Again, I ensured a significant amount of smoke was present before feeding it through the chimney and into the chamber.
To the great discomfort of my neighbors, who had to endure smoke alarms going off randomly, and to whom I sincerely apologize, I repeated the whole process three times per smoke detector model under test and per type of smoke, totaling six test runs per smoke detector. Finally, I averaged the response times. You can check them out in the chart below:
Other smoke detectors we’ve tested
First Alert SA320 Dual Sensor Smoke Detector: Ranked third in both tests, a solid option at an affordable price. The silence/test button is stiffer than most other models, which can be a pain if you’re trying to hush a false alarm or conduct a weekly test.
Kidde Firex PI2010 Hard-Wired Dual Sensor Smoke Detector: Lowest overall performance detecting a slow-smoldering fire, taking 83 seconds. Second-lowest performance detecting a fast-flaming fire, in 27.9 seconds. The device needs to be hard-wired, but it comes with a 9-volt battery as backup.
Onelink Battery Powered Smart Smoke and Carbon Monoxide Detector by First Alert: This model looked great at first. App-controlled, useful smart features, and it can be paired up with other smart home security devices, making it a strong contender for best for smart home. However, it did not impress us in the smoke detection test. It had the lowest performance detecting a fast-flaming fire and second-lowest performance detecting a slow-smoldering fire, taking almost twice as long as the Nest.
Smoke detector FAQ
Are there different types of smoke detectors?
Commonly, smoke detectors utilize different smoke detecting mechanisms, such as photoelectric sensors, ionization sensors or a combination of the two, called “dual sensors”. We don’t need to go too deeply into the science behind them but it’s useful to know that the main difference between the two is their ability to detect different types of smoke.
My smoke detector goes off, but there’s no smoke?
Some smoke detectors, like dual-sensors, and especially ionization detectors, are designed to sense disruptions in the circuitry of the device. The ionization sensor is inside a chamber, and has two electrically charged plates that ionize air between them. When smoke particles enter the chamber, they occupy the air within the plates, blocking the flow of ions and, consequently, triggering the alarm. Debris, dust, paint, cigarette smoke, dirt and steam particles can also have the same effect. Keep that in mind if you’re renovating your home or if you have your smoke detector installed near a kitchen. If you suspect your smoke detector has been contaminated with foreign particles, give it a good cleaning. Which leads us to…
How do I clean a smoke detector?
Smoke detectors will have instructions on how to clean the device in the user’s manual. However, there are a couple of easy fixes you can try if you don’t feel like looking for that elusive bit of paper. Grab a hand-held vacuum or a vacuum that’s equipped with the smallest nozzle piece. Then, simply vacuum every open spot you can find in your smoke detector. If you have an air blower, blow some air in those spots as well. If you’re renovating your home, make sure to cover your smoke detector or remove it from the work area to prevent it from going off when no smoke is present.
My smoke detector makes a chirping noise. What’s causing it?
Most smoke detectors will produce a low chirping noise, signaling their batteries are getting low or that the unit itself needs replacing. This is a common feature of most smoke detectors but occurs mostly during the night when your home’s temperature drops a couple of degrees. If the chirping continues during the day, it may be a sign of something else. Refer to your smoke detector’s manual for troubleshooting specific to your smoke detector model. Keep in mind that the average lifespan of a smoke detector is 10 years, so if your detector is close to that, it’d be a good idea to play it safe and replace it.
