Verdict: The Aqara U400 is one of the most compelling smart locks for households with a compatible iPhone or Apple Watch that want genuinely hands-free unlocking. Its UWB “Unlock on Approach” feature can open the door as you walk up, without tapping a phone, entering a PIN, or touching a fingerprint reader. At $269.99 in the U.S., however, it is not the obvious choice for Android users, renters, buyers without Thread infrastructure, or anyone who only needs basic keypad or fingerprint access.
What makes the Aqara U400 different?
Most Apple Home Key locks still require a deliberate tap: hold an iPhone or Apple Watch near the lock and authenticate through Apple Wallet. The U400 supports that approach, but adds UWB-based Unlock on Approach. With a compatible authorized device, you can walk toward the door with the phone in a pocket or bag and let the lock detect your approach.
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Aqara says the system evaluates proximity, direction, and presumed intent so that simply walking past or lingering near the door should not trigger an unlock. That is a design claim rather than a guarantee for every doorway layout, but it is the feature that separates the U400 from ordinary Home Key locks.
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In practical terms, UWB is most useful when your hands are occupied with groceries, children, packages, tools, or an umbrella. It also avoids touching a wet keypad or removing a phone from a pocket. The trade-off is that automatic behavior can feel less deliberate, and it gives you another system to troubleshoot when it does not respond.
#1 Best Overall
- True Hands-Free Unlocking with UWB Technology: Experience a new era of smart access — UWB (Ultra-Wideband) detects your incoming presence, direction, and intent to unlock automatically as you approach. It provides a faster, more convenient, and highly secure way to enter your home without touching the lock. Perfect when your hands are full, you're wearing gloves, or arriving in the rain. (Note: UWB unlocking requires a Thread-enabled Apple Home hub and is supported on Apple Watch Series 6 or later (excluding SE) running watchOS 11.5+ and iPhone 11 or later (excluding iPhone SE & iPhone 16e) running iOS 18.5+.)
- All-in-One Unlocking Options: Enjoy Apple home key tap-to-unlock (requires an Apple Thread-enabled Matter controller: HomePod 2nd Gen, HomePod mini, or Apple TV 4K 2021/2022), plus fingerprint, touchscreen passcode, voice assistant control, app remote access, NFC card support (card sold separately), and a physical key, giving you flexible, reliable ways to enter your home in any situation.
- Matter Over Thread for Multi-Ecosystem Compatibility: Built with Matter over Thread, the U400 can connect to multiple smart home platforms simultaneously, allowing you to enjoy the unique features of each ecosystem. Thread offers faster response, more stable connectivity, lower power consumption, and secure data transmission. Note: A Thread-enabled Matter controller from each ecosystem is required for its respective platform.
- Convenient Rechargeable Power System: Powered by a rechargeable and removable lithium battery that lasts up to 6 months per charge. Use the lock's USB-C port to recharge without taking the lock offline, or remove the battery and charge it separately. A low-battery voice alert will notify you when the battery drops below 20%, ensuring you never get caught off guard.
- Certified Security & Outdoor Durability: BHMA-certified for proven protection, mechanical strength, and long-term reliability. The IP65-rated exterior guards against dust and water for dependable outdoor performance. Plus, the rekeyable design allows you to change the physical key without replacing the entire lock cylinder.
UWB in real use
Independent testing by Tom’s Guide found UWB unlocking worked consistently, with occasional additional delay when using only an Apple Watch. The same review found the fingerprint reader quick and accurate, while the keypad sometimes required multiple taps to wake.
That produces a useful distinction: UWB is the reason to buy the U400, but fingerprint access may become your most practical fallback. The lock is not dependent on UWB alone. You can still use Apple Home Key tap-to-unlock, a fingerprint, a PIN, an NFC card, the Aqara app, supported smart-home controls, or a traditional key.
Aqara’s manual specifies hands-free unlocking for approaching from outside. Do not treat it as a universal automatic-unlock system for every direction or interior use case.
Compatibility: check this before buying
| Requirement or platform | What the U400 supports |
|---|---|
| iPhone UWB | iPhone 11 or later, excluding iPhone SE models and iPhone 16e, with iOS 18.5 or later according to Aqara’s current U.S. information. |
| Apple Watch UWB | Apple Watch Series 6 or later, excluding Apple Watch SE, with watchOS 11.5 or later. |
| Apple home hub | A Thread-enabled Apple home hub is required for the Apple Home setup, such as a HomePod mini, HomePod (2nd generation), or compatible Apple TV 4K. |
| Apple Home | Supports Home Key and the current UWB Unlock on Approach feature. |
| Google Home, Alexa, SmartThings, Home Assistant | Supported through Matter over Thread, but feature availability varies by platform. |
| Android | Fingerprint, keypad, NFC, physical key, Aqara app, and supported Matter functions remain available. Aqara’s current FAQ says UWB unlocking is currently Apple Home-only. |
The U400 uses Matter over Thread, not Wi-Fi. Matter compatibility does not make UWB a cross-platform feature, and it does not guarantee identical access to fingerprint enrollment, password management, logs, firmware updates, automations, or remote controls in every app.
Samsung Wallet support was announced for the first quarter of 2026. Treat that as a feature to verify for your country and device rather than assuming it is available everywhere.
Rank #2
- True Hands-Free Unlocking with UWB Technology: Experience a new era of smart access — UWB (Ultra-Wideband) detects your incoming presence, direction, and intent to unlock automatically as you approach. It provides a faster, more convenient, and highly secure way to enter your home without touching the lock. Perfect when your hands are full, you're wearing gloves, or arriving in the rain. (Note: UWB unlocking requires a Thread-enabled Apple Home hub and is supported on Apple Watch Series 6 or later (excluding SE) running watchOS 11.5+ and iPhone 11 or later (excluding iPhone SE & iPhone 16e) running iOS 18.5+.)
- All-in-One Unlocking Options: Enjoy Apple home key tap-to-unlock (requires an Apple Thread-enabled Matter controller: HomePod 2nd Gen, HomePod mini, or Apple TV 4K 2021/2022), plus fingerprint, touchscreen passcode, voice assistant control, app remote access, NFC card support (card sold separately), and a physical key, giving you flexible, reliable ways to enter your home in any situation.
- Matter Over Thread for Multi-Ecosystem Compatibility: Built with Matter over Thread, the U400 can connect to multiple smart home platforms simultaneously, allowing you to enjoy the unique features of each ecosystem. Thread offers faster response, more stable connectivity, lower power consumption, and secure data transmission. Note: A Thread-enabled Matter controller from each ecosystem is required for its respective platform.
- Convenient Rechargeable Power System: Powered by a rechargeable and removable lithium battery that lasts up to 6 months per charge. Use the lock's USB-C port to recharge without taking the lock offline, or remove the battery and charge it separately. A low-battery voice alert will notify you when the battery drops below 20%, ensuring you never get caught off guard.
- Certified Security & Outdoor Durability: BHMA-certified for proven protection, mechanical strength, and long-term reliability. The IP65-rated exterior guards against dust and water for dependable outdoor performance. Plus, the rekeyable design allows you to change the physical key without replacing the entire lock cylinder.
Apple users should also review Apple’s current Home Key support information alongside Aqara’s compatibility requirements.
How to enable Unlock on Approach
- Pair the U400 with Apple Home.
- Add or confirm the lock’s home key in Apple Wallet.
- Enable Express Mode during setup, or open Wallet app → Home Key → Enable Unlock on Approach.
- Make sure Bluetooth is enabled.
- Approach the door from outside with the authorized iPhone or Apple Watch.
Keep another access method configured. Automatic unlocking is a convenience feature, not a replacement for a fingerprint, PIN, tap-to-unlock option, or physical key.
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The U400 replaces the complete deadbolt assembly. It is therefore more involved than an interior retrofit lock that attaches to an existing thumb-turn. Before ordering, confirm that your door meets Aqara’s requirements for the bore hole, backset, strike plate, and door thickness.
Mechanical alignment matters as much as wireless connectivity. With the door open, the bolt should extend and retract smoothly. If it binds against the strike plate, a motor may sound weak, auto-locking may fail, battery life may suffer, and the lock may appear unreliable even when Thread and Apple Home are working correctly.
Calibration procedure
Aqara provides calibration through Aqara Home and a local method:
Rank #3
- 𝐅𝐥𝐞𝐱𝐢𝐛𝐥𝐞 𝐖𝐚𝐲𝐬 𝐭𝐨 𝐔𝐧𝐥𝐨𝐜𝐤: Unlock the way you want: app, passcode, fingerprint, physical key, or voice via Alexa/Google Assistant. Everyone in the family can choose what works best — convenience meets flexibility. Batteries are not included.
- 𝐔𝐧𝐥𝐨𝐜𝐤 𝐅𝐫𝐨𝐦 𝐀𝐧𝐲𝐰𝐡𝐞𝐫𝐞: Built-in Wi-Fi lets you lock and unlock your door remotely anytime, anywhere from your smartphone — no extra hub needed. Stay connected and in control, even when you’re at work or on vacation. Only support 2.4Ghz network. Keep the router and lock with 65ft for better remote control.
- 𝗩𝗼𝗶𝗰𝗲 𝗖𝗼𝗻𝘁𝗿𝗼𝗹 𝗥𝗲𝗮𝗱𝘆: Pair with Alexa or Google Assistant to unlock or lock with your voice. Great for when your hands are full or you're relaxing at home and still welcome who’s at the door. Note: Please log in to your own Google or Alexa account first before use Voice Control and make sure your network connection is stable.
- 𝗬𝗼𝘂𝗿 𝗙𝗶𝗻𝗴𝗲𝗿𝘀 𝗶𝘀 𝗬𝗼𝘂𝗿 𝗞𝗲𝘆: Just one touch unlocks the door instantly. No need to search for keys — Your fingers is your keys, perfect for busy mornings. Philips wifi lock store multiple prints for easy family access.
- 𝐂𝐨𝐝𝐞 𝐀𝐜𝐜𝐞𝐬𝐬 𝐌𝐚𝐝𝐞 𝐒𝐢𝐦𝐩𝐥𝐞: Create up to 100 custom passcodes for family, friends, or renters. Easily share unlimited one-time or scheduled codes to guests, cleaners, or deliveries— no need to be home to open the door.
- Connect the lock to an ecosystem.
- Press the lock’s Set button once to enter setup mode.
- Press 5 to enter calibration mode.
- Follow the voice prompts.
- Open the door, close it from inside, and lock it once so the lock can detect door status correctly.
Keep a physical key with you during calibration and testing. Do not close yourself outside until the lock has completed calibration and you have confirmed at least one backup method.
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- UWB Unlock on Approach: Hands-free unlocking for compatible Apple devices in Apple Home.
- Apple Home Key tap-to-unlock: Hold an iPhone or Apple Watch near the lock.
- Fingerprint: Stores up to 50 fingerprints. Aqara claims recognition in 0.3 seconds and accuracy up to 98.6%; these are manufacturer specifications, not independent laboratory measurements.
- Keypad: Supports permanent, offline, and scheduled passwords, plus anti-peep protection. Tom’s Guide found the keypad could require several taps to wake.
- NFC: Supports NFC cards, but Aqara lists the cards as a separate option and the card is not included in the package reviewed by Tom’s Guide.
- App and smart-home controls: Available where supported by Aqara Home or the chosen Matter ecosystem.
- Physical key: Provides mechanical backup access.
Battery, charging, and emergency entry
The U400 uses a removable rechargeable lithium-ion battery. Aqara advertises up to six months of battery life, but actual results depend on usage, temperature, connectivity, and settings. Treat six months as a stated estimate or maximum, not a guaranteed interval.
The exterior has a USB-C emergency-power port. Aqara says a power bank—and compatible USB-C phones—can temporarily power the lock. This port is for emergency power; it is not the normal charging connection for the removed battery. Removing the battery stops the lock from operating, so carry the physical key while charging it.
Aqara says UWB is disabled below 8% battery. That is a useful warning against total depletion, but it also means the headline feature can stop working before the lock itself becomes unusable. Set a charging routine and do not ignore low-battery alerts.
What Matter over Thread means in practice
You may not need an Aqara-branded hub for basic Matter pairing, but “no hub required” is too broad. Matter over Thread still needs the relevant ecosystem’s Matter controller and Thread Border Router. An Apple Home setup, for example, needs compatible Thread-enabled Apple home infrastructure.
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Rank #4
- ANYWHERE ACCESS: With built-in WiFi compatibility, you can easily and securely connect your Schlage Encode Plus lock to your home WiFi network to control and monitor your home from anywhere with the Schlage Home app
- PEACE OF MIND: Lock and unlock from anywhere, manage up to 100 access codes, view lock history, receive customizable notifications and easily manage multiple locks at once - all when paired to the Schlage Home app and connected to a secure WiFi network
- TAP TO UNLOCK: Works with Apple HomeKit and Apple home keys; with home keys you can simply tap to lock or unlock using your iPhone or Apple Watch for easy and secure access to your home
- VOICE CONTROL: Works with Amazon Alexa and Google Assistant for optional, hands-free convenience when paired with the Schlage Home app and a voice enabled device
- ADVANCED SECURITY: Secure, encrypted connection; built-in, customizable alarm for door movement and forced entry attempts; fingerprint-resistant touchscreen; certified highest residential Security, Durability and Finish rating by BHMA industry experts
Aqara’s manual says an Aqara Thread-enabled Matter controller such as the Aqara Hub M3 can enable additional remote functions, including remote periodic passwords and automations. Direct Bluetooth access through Aqara Home can provide certain exclusive features within Bluetooth range.
Choose the ecosystem before installation. The U400 can join Apple Home, Google Home, Amazon Alexa, Samsung SmartThings, and Home Assistant, but a shared Matter label does not mean the apps expose the same controls. If fingerprint enrollment, detailed password scheduling, access logs, firmware updates, or advanced automations matter to you, expect to use Aqara Home or confirm the exact capability in your preferred platform.
UWB troubleshooting
- Confirm Unlock on Approach is enabled in Wallet.
- Check that the iPhone or Apple Watch is supported and updated.
- Make sure Bluetooth is enabled.
- Look for the UWB indicator when approaching.
- Check that the battery is above 8%.
- Wake the keypad and try again.
- Toggle Unlock on Approach off and on.
- Confirm the U400 appears in Bluetooth settings.
- Verify that the lock is correctly paired to Apple Home and that the user has a valid home key.
- Try fingerprint or tap-to-unlock. If those also fail, investigate power, alignment, calibration, or the lock itself rather than UWB alone.
- Recalibrate if the bolt is not fully engaging or the door state is wrong.
- Keep the physical key available while troubleshooting.
There is no setting that can fix every failure. Door alignment, low battery, firmware, Bluetooth state, device compatibility, and Apple Home provisioning can all contribute.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Security and privacy
Fingerprint access is processed through the lock’s local reader, while Apple Home Key uses Apple Wallet credentials. Aqara says its UWB implementation uses encrypted, timestamped signals based on IEEE 802.15.4z and is designed to resist spoofing and relay attacks. That statement should be understood as Aqara’s security description, not independent proof that the U400 is universally more secure than every competing lock.
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Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Automatic unlocking also changes the risk profile. A deliberate tap or PIN gives you a clearer moment of intent; approach unlocking is more convenient but less visibly deliberate. Use only trusted authorized devices, review household and guest access, keep firmware updated, and maintain a physical fallback.
Best Value
- 【Apple Home and Home Key Support】The U100 is a smart door lock that is fully integrated into Apple Home. It can be unlocked with the Apple home keys by simply tapping an iPhone or Apple Watch, even when the iPhone or Apple Watch is out of power. Moreover, you can manage and share door access for your guests in Apple Home. (NOTE: To share Apple Home Keys, you need an Apple Home Hub)
- 【Fingerprint and More Ways to Unlock】The Smart Lock U100 offers multiple ways to unlock, including a high-precision fingerprint reader for up to 50 fingerprints, remotely configurable passwords via the Aqara Home app (An Aqara Zigbee 3.0 hub is required), one-time local passwords for visitors, and a mechanical key for emergency use. * The NFC card is not included and is sold separately.
- 【Automations with Aqara and Third-Party Devices】With an Aqara Zigbee 3.0 hub, the Smart Door Lock U100 is compatible with third-party ecosystems like Google Home, Alexa, IFTTT as well as the Aqara Home app, allowing it to be easily integrated into a wide range of smart home setups and used in smart home automations. For example, when someone presses the Aqara Video Doorbell G4, you will be able to view who is at your door and easily unlock the U100.
- 【Auto Lock & Do Not Disturb Mode】Thanks to the built-in gyroscope inside the lock, the auto-lock feature locks the door for you after you close it. Alternatively, you can disable this feature and leave the door always open. Also, the Do Not Disturb mode can mute the door lock sounds within a certain period of time, to avoid affecting your family’s sleep when you get back home late.
- 【A Durable and Secure Biometric door Lock with Long Battery Life】 The U100 is powered by 4 AA 1.5V batteries (included) and has a long battery life of up to 8 months. Also, a USB-C port for emergency charging is available. The lock body made of zinc alloy has an IP65 rating and complies with the same safety standard as BHMA Level 3. It’s capable of withstanding temperatures ranging from -31°F to 151°F. Your sensitive data (e.g., fingerprints) is stored locally and fully AES encrypted.
The exterior panel is rated IP65 according to Aqara’s documentation. That applies to the outside panel and should not be interpreted as saying the entire installed lock is submersible.
Guest access
Apple Home residents and guests can be appropriate for households already using Apple devices, while non-Apple visitors may be better served with a temporary or recurring PIN. Fingerprints can also suit regular household members, but each method depends on the management controls exposed by the ecosystem you choose.
Do not assume that Apple Home, Aqara Home, Google Home, Alexa, SmartThings, and Home Assistant offer identical guest-management, scheduling, logging, or offline behavior. Configure access in the platform that will actually manage the lock, and provide a non-phone fallback for guests whose device is unavailable.
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| Choose this direction | Why |
|---|---|
| Aqara U400 | Best fit for an eligible Apple household that specifically wants hands-free approach unlocking and multiple fallback methods. |
| Schlage Encode Plus | Better suited to buyers who want an established Apple Home Key experience based on deliberate tap-to-unlock rather than UWB approach unlocking. |
| Yale Assure Lock 2 Touch with Wi-Fi | A stronger direction for buyers prioritizing fingerprint entry over hands-free Apple access. |
| Level Lock+ | More appropriate for buyers who prioritize discreet exterior hardware and Apple Home Key, not a visible fingerprint reader or UWB. |
| Aqara U100 | The closer Aqara comparison if you want fingerprint, keypad, and Apple Home Key features without paying specifically for UWB approach unlocking. |
Prices, regional availability, colors, bundle contents, warranties, door compatibility, and platform features can change. Confirm those details before purchase, especially whether a hub or NFC card is included.
Who should buy the Aqara U400?
Buy it if you use an eligible iPhone or Apple Watch, have or want a Thread-enabled Apple home hub, value hands-free entry enough to pay a premium, and are comfortable replacing a complete deadbolt and maintaining a rechargeable battery.
Consider it carefully if your household mixes Apple and Android devices or you plan to manage it through multiple Matter ecosystems. The lock can still work well through fingerprint, PIN, NFC, or physical access, but the UWB advantage will not apply equally to everyone.
Skip it if you are Android-only and want UWB today, rent and cannot replace the deadbolt, prefer ordinary replaceable batteries, have a poorly aligned door, or only need an inexpensive keypad or fingerprint lock.
For the right Apple household, the U400 makes unlocking feel unusually close to walking through an open door. For everyone else, its premium is paying for a feature they may not be able to use.
Quick Recap
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