Battery powered alarms can be installed easily and all models include a test button, hush button, power indicator light, battery locking, and low battery warning indicator. Kidde battery operated smoke alarms offer an inexpensive and easy way to protect homes that don't have hardwired smoke alarms.

CR's take: Another top performer in our tests is the Kidde PI2010, which receives the highest scores possible in our flaming fire and smoldering fire tests. This hardwired, dual-sensor alarm features a battery backup, a hush button, and the ability to interconnect with other compatible detectors.

Kidde offers photoelectric and ionization smoke alarms as well as a dual-sensor alarm that combines both technologies in one unit, all of which meet the current UL standard for smoke alarms and can be purchased nationwide at retailers or online.

10-year The smoke alarm shall be Kidde unit i9010/i9010CA or approved equal. It shall be powered by a non-replaceable lithium battery with a 10-year life. The lithium battery shall be sealed in the unit to prevent removal and/or tampering.

A proprietary radio signal joins multiple alarms together so that when one alarm sounds, they all sound. Wire-free or hardwire interconnect triggers each connected alarm in the network to sound once smoke or CO is detected, which can provide more time to react to a hazard.

Smoke sensitivity; 2.31+/-1.37%/FT Obscuration(UL stan- dard),0.086dB/m~0.140dB/m Power supply: 9V battery;100/110/120/220/230/240 VAC,50/60HZ for AC versions Battery Life: At least 30 months under normal conditions with Alkaline cell Battery Low Battery life: Up to 30 days warning signal Alarm Indicator: Continuosly ...

Overall, we recommend the First Alert SA3210 because it combines photoelectric and ionization sensors that detect low and smoky fires as well as high flames. It's also battery-operated, so it's easy to install. If you're looking for a bargain, the Kidde I9030 is a basic smoke detector that does the job at low cost.

Best Overall For a reliable, long-lasting, and effective smoke detector, we recommend the First Alert BRK 3120B Smoke Detector. This 10-year, hardwired model is equipped with both a photoelectric and an ionization sensor. “Dual detectors allow the device to detect both smoky fires and flames,” says Mock.

Mechanical point sensors are working according to the principle of specific thermal expansion: If a fixed temperature is exceeded a signal is transmitted to the corresponding control unit. After the fire is extinguished and the temperature had dropped down the point sensor simply resets.

Generally, there are two types of home smoke alarms: photoelectric and ionization.

Ten-year sealed battery smoke alarms are powered by sealed lithium batteries that have a life span of ten years.

It is recommended you test your alarms at least once a month to ensure they are working properly, and replace the batteries in your smoke alarm every six months. The detector itself should be replaced at least every ten years. For 10-year lithium-powered smoke alarms, you won't need to replace the battery.