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What Type of Batteries Does a Smoke Detector Take? 4 Types

The smoke detector is probably the most important safety device in your home, along with a carbon monoxide detector. It works around the clock to keep you and your family safe by detecting smoke particles and sounding an alarm, giving you more time to react. However, most of these devices run on batteries. Many people are concerned about what type of batteries they need and when to change them. If you are new to maintaining smoke detectors in your home, keep reading as we look at the different types of batteries that you might need and how long they last.

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The 4 Types of Smoke Detector Batteries

1. The 10-Year Sealed Lithium Battery

replacing smoke detector battery
Photo Credit By: Andrey_Popov, Shutterstock

One of the best options available to anyone looking to keep their home safe from fire is the 10-year sealed lithium battery smoke detector. As the name suggests, the lithium battery is built into the smoke detector and will last 10 years without any maintenance from you. When it’s time, you replace the unit with a new model. With a battery that lasts 10 years, you never need to worry about a lapse in coverage simply because you forgot to change a dead battery. Another benefit of these modern units is that many also have a built-in carbon monoxide detector.

2. The Alkaline 9-Volt Battery

The alkaline 9-volt battery is likely the most popular solution for powering smoke detectors in homes across America. Depending on the brand, these batteries usually last 6 months to 1 year. High-end batteries will last longer, while budget batteries will lose their charge faster. However, the difference isn’t likely to be too noticeable. These batteries lose their power slowly, so you have more time to change the battery once the low-battery alarm starts, to keep it from shutting off completely.

3. The Lithium 9-Volt Battery

man replacing smoke alarm battery
Photo Credit By: Andrey_Popov, Shutterstock

Lithium 9-volt batteries can hold their charge up to five times longer than a standard alkaline 9-volt battery, meaning you will hear fewer low-battery alarms. You can swap out an alkaline battery for the lithium version to take advantage of its longevity, but it is not without downsides. Lithium batteries are far more expensive than alkaline batteries, and they hold their full charge until the end of their lifespan, meaning you will have little time to replace the battery before the smoke alarm shuts down and stops protecting your home.

4. The AA Battery

Smoke detectors that use AA batteries are a great middle-of-the-road option for many people. These are alkaline batteries, but they last longer than the 9-volt versions, and the detectors can take two or three batteries, enabling some brands to also incorporate a carbon monoxide detector. Since these batteries lose their charge slowly, there’s plenty of time to change them once the low-battery alarm starts. The downside to AA batteries is that they don’t last as long as lithium ones, so you will need to change them frequently.

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How Do I Change the Battery in a Smoke Detector?

The steps to changing a battery in a smoke detector can vary from unit to unit, so it’s best to refer to your owner’s manual for the instructions. However, most smoke detectors sit on a base. Twisting or sliding the detector will help you remove it, gaining access to the battery compartment. Replace the old battery with a new one. The unit will often produce a test tone to show you that the battery works. Then, twist or slide the detector back onto its base.

How Many Smoke Detectors Should I Have?

You should have a smoke detector on every floor of your home, including the basement and attic. You need one close to your kitchen and at the top of any stairways. It’s also important to have a smoke detector in every divider


You will find one of four battery types in most smoke detectors: a 10-year sealed lithium battery, an alkaline or lithium 9-volt battery, and AA batteries. We recommend the 10-year sealed lithium battery if you are purchasing new alarms for your home. If these alarms are too expensive, go with one that uses AA batteries and has a carbon monoxide detector. If you are going with a 9-volt option, remember that lithium will last longer, but there is a greater chance that your home will go unprotected when the battery dies.

Featured Image Credit: MashaSay, Shutterstock


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