Replace the battery by opening the detector's cover, removing the old battery, and inserting a new one of the same type

ADT smoke detectors use a 9-volt battery as a backup power source. When the battery runs low, the detector will chirp every 30 to 60 seconds — that's your signal to replace it. The process takes less than a minute and requires no tools.

Most ADT detectors have a cover that twists or slides off. Once you open it, you'll see the battery mounted in a clip or holder. Write down the battery type printed on the holder before you go to the store — usually it says 9V. Buy an identical replacement, pop out the old one, and slide the new one in. The chirping should stop within a few minutes as the detector recognizes the fresh battery.

Key Takeaways

  • ADT smoke detectors chirp every 30 to 60 seconds when the battery is low, which is the signal to replace it.
  • The battery type is printed on the holder inside the detector — write it down before shopping so you buy the right one.
  • The detector cover twists or slides off by hand; no screwdriver or special tool is needed.
  • After you insert the new battery, wait a few minutes for the chirping to stop and the detector to recognize the fresh power.
  • If the chirping continues after you replace the battery, the detector itself may be faulty and should be replaced.

Locate the battery compartment on your detector

Look at the bottom or side of your ADT smoke detector. You'll see a cover or panel — this is the battery compartment. Some covers twist counterclockwise a quarter turn; others slide straight down or to the side. Check the detector itself for arrows or text that shows which direction to turn or slide.

If the cover is stuck, do not force it. Gently wiggle it while turning or sliding. If it still won't budge, the detector may be mounted too tightly to the ceiling or wall bracket — in that case, loosen the bracket slightly first, then open the cover.

Remove the old battery safely

Once the cover is open, you'll see the battery held in a plastic clip or spring-loaded holder. The battery terminals — the metal bumps on the ends — should face a specific direction, usually marked with a plus or minus sign on the holder.

Gently pull the battery straight out. If it's stuck, wiggle it slightly side to side while pulling. Do not pry it with a metal tool, as that can damage the holder or create a spark. Once it's out, set it aside. If the battery is swollen, leaking, or discolored, do not touch it directly — wash your hands after handling it and dispose of it at a battery recycling center or retailer that accepts old batteries.

Install the new battery in the correct direction

Before you insert the new battery, check the holder again for the plus and minus symbols. The positive terminal (marked +) should face the direction shown. Most 9-volt batteries have a snap connector on top, but some older ADT models use a clip holder instead.

Slide or snap the new battery into place, making sure it sits fully in the holder. You should hear a small click if it's a snap connector, or feel it settle firmly if it's a clip. Do not force it — if it doesn't fit smoothly, remove it and check that you're inserting it the right way.

Close the cover and test the detector

Twist or slide the cover back into place until it's snug. You do not need to tighten it hard — just enough that it won't fall off. Within a few minutes, the chirping should stop as the detector recognizes the new battery.

If the chirping continues after 10 minutes, remove the cover again and check that the battery is fully seated in its holder. If it is, the detector itself may have failed and should be replaced. If the chirping stops but returns within a week, the new battery may be defective — try a different brand or a fresh battery from a different package.

What to do if your detector keeps chirping

A detector that chirps even after a new battery is installed usually means one of three things: the battery is not fully seated, the detector is at the end of its lifespan, or the battery itself is faulty.

Start by opening the cover again and pressing the battery firmly into its holder. Make sure both terminals are making contact with the metal springs or clips. Close the cover and wait 10 minutes. If it still chirps, try a different new battery from a different store or brand — sometimes a single battery is defective.

If a second new battery does not stop the chirping, the detector itself has likely reached the end of its life. Most smoke detectors last 8 to 10 years. Contact ADT to report the issue — they may replace the detector under warranty or as part of your monitoring service agreement. Do not ignore a chirping detector; it means the device is not fully operational.

When to call ADT for help

If you open the cover and the battery holder is corroded, cracked, or leaking fluid, do not attempt to fix it yourself. Contact ADT and describe what you see. They can send a technician to replace the detector or the entire unit.

If your detector is hardwired to your ADT system (meaning it has wires running to a control panel), the battery is a backup only. Changing it will not affect your monitoring service. However, if you are unsure whether your detector is hardwired, take a photo of the inside and contact ADT before you open it — they can walk you through it or send someone to do it for you.

Frequently Asked Questions

What type of battery does an ADT smoke detector use?

Most ADT smoke detectors use a standard 9-volt battery. The exact type is printed on the holder inside the detector. Buy the same type and brand if possible, as some batteries perform better in certain detectors.

How often should I replace the battery?

Replace the battery when the detector chirps. In most homes, this happens once a year, though it depends on the battery brand and how often the detector runs. Some people replace batteries on a set date each year, like when they change their clocks for daylight saving time.

Can I use a rechargeable battery in my ADT detector?

No. ADT detectors are designed for single-use alkaline batteries. Rechargeable batteries have a different voltage and may not power the detector reliably or trigger the low-battery chirp when they are actually depleted.

What if I lost the cover to my detector?

Contact ADT and ask them to send a replacement cover. Do not leave the detector open, as dust and insects can enter the chamber and damage the sensor. If you need the detector to work when ready, cover the opening loosely with a small piece of tape until the new cover arrives.

Is it safe to change the battery myself, or should I call ADT?

Changing the battery is safe to do yourself — it takes one minute and requires no special training. You only need to call ADT if the cover is stuck, the holder is damaged, or the detector is hardwired and you are unsure how to open it.