Aqara U100 Smart Lock: Setup Tips, HomeKit Integration, and Matter with Home Assistant

When I was looking for a smart lock to add to our smart home setup, I wanted to make sure it worked well for my family’s situation.

• Works with Apple Home Key (everyone in the house uses Apple devices)
• Integrates with Home Assistant
• Offers multiple unlock methods: PIN, NFC, fingerprint, and traditional key
• Works in the cold North Dakota winters
• Looks good on the door (my wife’s requirement)

The Aqara U100 seemed like it checked those boxes. Here’s how it went.

Devices Used

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• Aqara U100 Smart Lock
• Aqara Hub
• MIFARE Classic 1k NFC Tags

If you want to use Apple Home Key with multiple people, you’ll need a home hub like the HomePod, HomePod Mini, or Apple TV. Of course, you’ll also need an iPhone—and optionally an Apple Watch.

Installation Experience

The installation is straightforward and is very similar to installing a standard deadbolt lock. The Aqara app does a great job of guiding you through the physical installation and the initial setup. I did need to adjust the strike plate on the doorjamb, as it was too tight for the lock to consistently engage. It had been like that since the day we moved in—I just finally had a reason to fix it.

I did have one instance where the lock wasn’t working. I found the cable that connects the inside and outside parts of the lock was getting pinched. I wrapped it with electrical tape to protect it a little more and haven’t had any issues since.

I’ve found the batteries last about a year for my use case. We mostly use the garage to enter the house and use the front door a few times a day in the summer when walking the dogs. I use lithium batteries. Since the battery compartment is on the inside of the door, I don’t need to worry about them freezing in the winter. Using the Battery Notes integration from HACS is great for getting reminders whenever batteries need to be replaced in any of your smart home devices.

After the lock is installed, the Aqara app will walk you through creating an initial user, setting up a PIN, and adding your fingerprints.

Adding Additional Users

1. Open the Aqara App
2. Touch Accessories
3. Touch your Smart Lock U100
4. Touch User Management
5. Touch Add under Admin or General User depending on the type you are adding
6. Enter a name
7. Touch Add under Fingerprint and follow the instructions
8. Touch Add under Password and follow the instructions

HomeKit Integration (iOS & Apple Watch)

Under the battery cover there is a HomeKit QR code and a HomeKit button.

1. Open the Home app on your iPhone
2. Touch the + > Add Accesory
3. Press the HomeKit button on the lock
4. Scan the HomeKit QR code on the lock with your phone
5. Follow the steps to finish setting up the lock and HomeKey

Home Assistant via Matter

If you’ve already connected your Aqara Hub to Home Assistant using Matter, the U100 Smart Lock should show up automatically as a Matter device—no extra steps needed.

If this is your first time setting up Matter with an Aqara Hub, here’s how to get started:

1. Open the Aqara app on your iPhone
2. Tap Accessories
3. Select your hub
4. Tap the three dots in the top right
5. Tap Expose to Matter
6. Tap Matter Pairing Code
7. Tap Copy pairing code

Now switch over to Home Assistant:

1. Open the Home Assistant Companion App
2. Tap the hamburger menu (☰)
3. Tap Settings
4. Tap Devices & Services
5. Tap Add Integration
6. Tap Add Matter Device
7. Tap No, it’s new
8. Tap More options…
9. If your Aqara Hub appears, select it. If not, tap My Accessory Isn’t Shown Here
10. When prompted, paste the Matter code:
    • If you selected the Hub, it may auto-fill—just confirm it.
    • If not, tap Enter Code and paste it manually.
11. Tap Continue

Adding Additional Users

1. Open the Aqara App
2. Tap Accessories
3. Tap your Smart Lock U100
4. Tap User Management
5. Tap Add under Admin or General User depending on the type you are adding
6. Enter a name
7. Tap Add under Fingerprint and follow the instructions
8. Tap Add under Password and follow the instructions

HomeKit Integration (iOS & Apple Watch)

Under the battery cover there is a HomeKit QR code and a HomeKit button.

1. Open the Home app on your iPhone
2. Tap the + > Add Accessory
3. Press the HomeKit button on the lock
4. Scan the HomeKit QR code on the lock with your phone
5. Follow the steps to finish setting up the lock and HomeKey

Home Assistant via Matter

If you’ve already connected your Aqara Hub to Home Assistant using Matter, the U100 Smart Lock should show up automatically as a Matter device—no extra steps needed.

If this is your first time setting up Matter with an Aqara Hub, here’s how to get started:

1. Open the Aqara app on your iPhone
2. Tap Accessories
3. Select your hub
4. Tap the three dots in the top right
5. Tap Expose to Matter
6. Tap Matter Pairing Code
7. Tap Copy pairing code

Now switch over to Home Assistant:

1. Open the Home Assistant Companion App
2. Tap the hamburger menu (☰)
3. Tap Settings
4. Tap Devices & Services
5. Tap Add Integration
6. Tap Add Matter Device
7. Tap No, it’s new
8. Tap More options…
9. If your Aqara Hub appears, select it. If not, tap My Accessory Isn’t Shown Here

10. When prompted, paste the Matter code:

    • If you selected the Hub, it may auto-fill—just confirm it.
    • If not, tap Enter Code and paste it manually.
11. Tap Continue

Third-Party NFC Tags

Why You Need MIFARE Classic 1k NFC Tags

One of the features that drew me to the Aqara U100 was the ability to unlock it with NFC tags. I already had some NTAG215 keychain tags lying around, figured I’d toss one on my keys and maybe hand a few out to family.

Nope.

The lock didn’t react at all. No beep, no error—just silence.

After some digging, I found the issue: the U100 only supports MIFARE Classic 1k tags. The NTAG215 tags I tried use a different NFC standard (ISO 14443-A), which the lock doesn’t recognize or respond to.

Here’s the gist:

• NTAG215 and similar tags are great for phones and most NFC automations, but the U100 ignores them.
• MIFARE Classic 1k uses a different protocol and memory structure, and that’s what the lock is built to read.
• There’s no fallback. If it’s not a MIFARE Classic tag, the U100 pretends it doesn’t exist.

Once I switched to MIFARE Classic 1k keychain tags, everything worked perfectly. I’ve now got one on my keyring and a few extras set aside for my parents or anyone I trust with access to the house.

It’s a solid option if you don’t want to store your fingerprint, and you don’t use the lock often enough to reliably remember a PIN. Just tap the tag and walk in.

Adding Tags in the App

You’ll use the Aqara app on your phone to assign each NFC tag.

1. Open the Aqara App
2. Tap Accessories
3. Tap your Smart Lock U100
4. Tap User Management
5. Tap the user you want to assign the tag to
6. Tap Add under NFC Device
7. You’ll be instructed to place the tag near the NFC reader on the lock
8. When the tag is detected, the app will prompt you to name the tag.

Sample Home Assistant Automations

This automation locks the door 5 minutes after it’s been unlocked—but only if the door is actually closed. It’s a nice fallback in case someone forgets to lock up, and it helps prevent the lock from trying (and failing) to engage while the door is still open.

alias: Auto Lock Front Door
description: "Automatically re-locks the door 5 minutes after it’s unlocked, if the door is closed."
trigger:
  - platform: state
    entity_id:
      - lock.[LOCK_ENTITY_ID]
    to: "unlocked"
    for:
      minutes: 5
condition:
  - condition: state
    entity_id: binary_sensor.[DOOR_CONTACT_SENSOR]
    state: "off"  # off = closed for most contact sensors
action:
  - service: lock.lock
    target:
      entity_id: lock.[LOCK_ENTITY_ID]
mode: single

This automation sends a push notification to your phone whenever the front door is unlocked. It’s a simple way to keep track of who’s coming and going—especially useful if you’ve given out NFC tags or temporary access codes to family or guests.

alias: Notify on unlock
description: "Sends a notification when the front door is unlocked."
trigger:
  - platform: state
    entity_id: lock.[LOC_ENTITY_ID]
    to: 'unlocked'
action:
  - service: notify.mobile_app_[device]
    data:
      message: "Front door was unlocked."

This automation turns on the entryway light when the front door is unlocked after sunset. It’s a small touch that makes coming home feel a little more welcoming—especially when your hands are full or it’s dark out. It also avoids turning the light on unnecessarily by checking that it’s currently off before running.

alias: Turn On Light When Door Unlocks After Dark
description: "Turns on the entry light when the door is unlocked after sunset."
trigger:
  - platform: state
    entity_id: lock.[LOCK_ENTITY_ID]
    to: "unlocked"
condition:
  - condition: sun
    after: sunset
  - condition: state
    entity_id: light.[ENTRY_LIGHT]
    state: "off"
action:
  - service: light.turn_on
    target:
      entity_id: light.[ENTRY_LIGHT]
mode: single

Final Thoughts

I’ve had the Aqara U100 Smart Lock for a little over a year now. It’s worked great, and I recommend it often when people ask for smart lock suggestions.

My favorite feature? Taking the dogs for a walk without needing to bring keys. If you’re an Apple user, the HomeKey feature is excellent—just walk up to the door and tap your phone or watch.

Being able to unlock the door remotely or grant temporary access to someone while we’re out of town has come in handy more than once.