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Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →Aqara’s U400 is a genuine hands-free smart lock for Apple households. With a compatible iPhone or Apple Watch, it can use ultra-wideband (UWB) to detect your approach and unlock without tapping the lock, opening an app, entering a PIN, or using a fingerprint. That convenience comes with important conditions: compatible Apple hardware, an up-to-date Apple Home and Thread setup, a suitable single-cylinder deadbolt, and acceptance of a relatively bulky replacement lock.
Aqara calls the U400 “one of the world’s first” smart locks with Apple’s UWB-based Unlock on Approach. That is more defensible than calling it definitively “the first”: the available announcements establish Aqara’s early position, not an independently verified industry-wide first. Aqara product page · Aqara CES announcement
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Quick verdict
- Best feature: true hands-free Apple entry when Unlock on Approach is properly configured.
- Biggest requirement: an eligible iPhone or Apple Watch plus compatible Apple Home and Thread infrastructure.
- Biggest drawbacks: price, installation complexity, exterior bulk, and dependence on a carefully configured ecosystem.
- Best buyer: an Apple Home household that values invisible entry and wants fingerprint, PIN, NFC, app, and key fallbacks.
As of August 18, 2026, Aqara listed the standard U400 at $269.99 in the United States. Apple listed a $299.95 Deluxe Kit with different package contents. Prices and availability can change, so check the current product pages before buying. Aqara · Apple
What UWB adds to Apple Home Key
Ordinary Apple Home Key is a tap-to-unlock system: hold an eligible iPhone or Apple Watch near the lock and authenticate through the device. It is convenient, but it still requires a deliberate gesture.
#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.
The U400’s Unlock on Approach is different. UWB measures distance and direction using techniques Aqara identifies as Time of Flight and Angle of Arrival. The intended behavior is that an authorized device in your pocket or bag is recognized as you approach the door, rather than unlocking merely because it happens to be nearby.
| Feature | Apple Home Key tap | UWB Unlock on Approach |
|---|---|---|
| User action | Hold the device near the lock | Walk toward the lock |
| Device support | Broader | Narrower |
| UWB hardware required | No | Yes |
| Wallet Home Key required | Yes | Yes |
| Phone in pocket or bag | Not the intended use | Yes, according to Aqara |
| Best role | Reliable fallback or primary tap method | Hands-free convenience |
That distinction matters. A phone may support Home Key tap-to-unlock but not UWB approach unlocking. Aqara also claims that precise ranging and scrambled timestamp sequences help reduce accidental unlocking and relay attacks. Those are manufacturer claims, not proof that every installation is immune to relay attacks or false triggers. Approach direction, door position, nearby walkways, firmware, and network setup can all affect behavior.
Independent testing by Tom’s Guide found UWB unlocking worked consistently in most tests, with occasional additional delay when using only an Apple Watch. That is useful evidence, but it should not be treated as a guarantee for every phone, watch, door, or installation.
Which Apple devices support it?
Aqara’s published requirements for UWB Unlock on Approach, current as of August 18, 2026, are:
- iPhone 11 or later, excluding the second- and third-generation iPhone SE and iPhone 16e, running iOS 18.5 or later.
- Apple Watch Series 6 or later, excluding Apple Watch SE, running watchOS 11.5 or later.
For ordinary Home Key tap-to-unlock, Aqara lists broader support:
- iPhone XS or later with iOS 17.1 or later.
- Apple Watch Series 4 or later with watchOS 10.1 or later.
In practical terms, an older compatible iPhone or Apple Watch may still provide tap-to-unlock while being unable to provide the UWB feature that justifies the U400’s premium. Check the exact model and operating-system version before purchasing. Aqara’s requirements
What hub and network infrastructure is needed?
The U400 supports Matter over Thread, Bluetooth, NFC, and UWB. Matter broadens compatibility with Apple Home, Google Home, Amazon Alexa, Samsung SmartThings, and Home Assistant, but it does not make every feature identical across platforms.
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- 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.
For Apple Home, Aqara lists these compatible hubs:
- HomePod mini
- HomePod, second generation
- Apple TV 4K, second generation
- Apple TV 4K, third generation with Wi-Fi + Ethernet
The hub needs compatible, current software and Thread support. A phone alone is not necessarily a complete remote Apple Home setup. An Apple Home hub, a Thread Border Router, and a Matter Controller can overlap in one device, but they are not automatically the same role in every setup.
An Aqara hub is not universally required for basic Matter operation. It can, however, be useful for Aqara-specific remote control, automations, firmware management, and integrations. The required hardware depends on the ecosystem and the features you want. Aqara’s ecosystem information
Recommended setup order
- Leave the lock in its factory-default state while starting setup.
- Install the physical lock and confirm that the deadbolt moves smoothly without forcing the door.
- Add the U400 to Apple Home first using its Matter pairing code.
- Confirm that Apple Home Key is created in Apple Wallet.
- Open Wallet and verify that Unlock on Approach is available and enabled.
- Add the lock to Aqara Home over Bluetooth for fingerprints, user management, logs, firmware, and Aqara-specific settings.
- If required, bind it to an Aqara Thread-enabled Matter hub for Aqara remote control and automation.
Aqara’s support guidance also calls for Bluetooth during setup, the phone and hub to be on the same Wi-Fi network, and the lock to be close to the Thread Border Router during commissioning. IPv6 may be needed for Matter in some network configurations. These are practical setup conditions rather than universal hard distance limits.
Aqara’s forum guide recommends Apple Home first, followed by Aqara Home and then an Aqara Matter controller. Because support instructions can change, consult the current Aqara setup guidance before pairing.
The Tool Desk
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The U400 is a replacement deadbolt, not simply an interior retrofit module that clips onto an existing deadbolt. Tom’s Guide found installation more involved than a retrofit lock because the existing assembly must be replaced.
Aqara specifies compatibility with single-cylinder deadbolts and warns that modifications may be needed when door dimensions differ. It recommends installing the supplied strike plate. Before ordering, check:
- single-cylinder versus double-cylinder deadbolt;
- door thickness and backset;
- bore-hole and edge-bore dimensions;
- strike-plate alignment;
- interior clearance for the larger inside panel;
- whether the door closes and latches without pressure on the bolt.
Aqara lists approximate dimensions of 7.01 × 2.99 × 1.85 inches for the interior panel and 6.58 × 2.99 × 1.01 inches for the exterior panel. The exterior keypad is IP65-rated, but that does not make the entire lock assembly waterproof. Aqara specifications
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.
After installation, test the lock with the door open, then closed. The bolt should extend and retract smoothly. A lock that needs the door pulled, pushed, or lifted is not correctly aligned, and smart features will not solve that mechanical problem.
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The U400 is not dependent on one wireless feature. Its access methods include:
- UWB Unlock on Approach;
- Apple Home Key tap-to-unlock;
- fingerprint recognition;
- PIN codes;
- temporary, recurring, scheduled, and offline passwords;
- Aqara NFC cards;
- Aqara and compatible smart-home apps;
- voice assistants;
- traditional mechanical keys.
Aqara says the fingerprint reader stores up to 50 fingerprints and quotes 0.3-second recognition and up to 98.6% recognition accuracy. Those are manufacturer specifications, not independent test results. Aqara NFC cards are sold separately.
PIN capacity is more complicated: Tom’s Guide reported support for up to 75 PIN codes in its tested configuration, while Aqara’s product material emphasizes different user limits. Treat the number as dependent on the app, ecosystem, firmware, and regional configuration rather than a universal specification. Fingerprint enrollment may also require Aqara Home even when day-to-day control happens in Apple Home.
What happens when UWB fails?
Hands-free unlocking is a convenience feature, not a guarantee. A sensible fallback order is:
- Try Apple Home Key tap-to-unlock.
- Use the fingerprint reader.
- Enter a PIN.
- Use the Aqara or compatible smart-home app.
- Use a configured NFC card.
- Use the physical key.
- If the battery is depleted, provide emergency power over USB-C.
If tap-to-unlock works but UWB does not, check the following before resetting the lock:
- the iPhone or Watch model and OS version;
- that the correct Home Key is in Wallet;
- that Unlock on Approach is enabled;
- that the Apple Home hub and Thread network are online;
- that the hub is close enough to the lock;
- that the phone or watch is approaching the door from the expected direction;
- firmware and network settings, including IPv6 where required.
Restart the phone, Watch, and Home hub before unpairing or resetting anything. Aqara support reports include cases where Home Key tap-to-unlock worked while UWB did not, with possible connections to Thread routing, firmware, IPv6, or antenna issues. These are user-support reports, not proof of a systemic defect. Example report · Another report
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
Battery life and emergency entry
Aqara claims up to six months per charge. Apple lists seven months for its Deluxe Kit, so the published figures are not identical. Real battery life depends on lock cycles, fingerprint and UWB use, connectivity, temperature, and settings.
The battery is removable and rechargeable. The U400 has USB-C charging and emergency-power support; Aqara says a power bank or compatible USB-C phone can provide temporary power. A physical key is also included, and the cylinder is rekeyable. Keep the key somewhere accessible outside the locked home.
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Do not wait for a failure. Enable low-battery alerts, charge the battery on a schedule, and test the USB-C emergency procedure before you need it. Aqara battery information · Apple Deluxe Kit specifications
Auto-lock and real-world behavior
The U400 uses a gyroscope-based auto-lock-on-close feature. Tom’s Guide reported that it worked most of the time but could occasionally take several seconds, and warned that time-based auto-lock may lock the door before expected if the door has not fully closed.
Test the door’s alignment, the bolt’s resistance, the closed-door detection, and any delay setting. A separate contact sensor may be useful if you need a more certain open/closed state. Be especially cautious with auto-lock on doors used by children, tradespeople, or anyone carrying bulky materials.
UWB can also be less predictable at doors beside walkways, shared walls, or approaches that come from the side. Someone walking past the entrance should not be assumed to produce the same result as someone walking directly toward it. Test the actual path to the door, not just a demonstration from directly in front of the lock.
Smart-home limitations
Matter support means the U400 can join several ecosystems, but it does not guarantee feature parity. Core lock and unlock controls may appear in Apple Home, Google Home, Alexa, SmartThings, and Home Assistant while Aqara-specific functions remain in Aqara Home.
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.
| Function | Likely role of Aqara Home | What to verify elsewhere |
|---|---|---|
| Lock and unlock | Available | Local versus remote control |
| Fingerprints | Enrollment and management | Usually not exposed as a standard Matter feature |
| PINs and guest access | Advanced management | Platform-specific support and limits |
| Activity logs | Aqara-specific logs | Whether the chosen platform exposes them |
| Firmware | Typically managed through Aqara | Third-party update support |
| UWB approach unlocking | Apple-focused feature | Do not assume Google, Alexa, or SmartThings support it |
Samsung Wallet support was announced for the first quarter of 2026, but availability should be verified for the reader’s region, device, and current firmware rather than assumed from the announcement. The UWB feature was initially Apple-only.
Is the U400 secure?
The U400’s security case combines precise UWB ranging, Apple Wallet credentials, local access methods, a rekeyable cylinder, and physical fallback. Aqara claims its secure-ranging design helps protect against relay attacks. That claim should be attributed to Aqara, not presented as an independently certified conclusion.
Buyers should still ask practical questions:
- What exact BHMA grade applies to the regional model?
- Does the certification cover the complete installed lock?
- What happens if a PIN is shared or exposed?
- How are fingerprints stored and removed?
- Can UWB be disabled for a particular user or device?
- Can the approach area be configured for a door beside a public path?
- What alerts are generated for forced entry, an open door, or auto-lock?
Tom’s Guide reported that UWB and fingerprint unlocking continued to work locally in its test environment, but that should not be generalized to every app, automation, or remote function. Internet loss, Thread failure, Bluetooth availability, and battery state affect different features differently.
Who should buy it?
Buy the U400 if your household is heavily invested in Apple Home, someone has a compatible iPhone or Apple Watch, you already have—or are willing to add—a compatible Apple Thread home hub, and hands-free entry is worth paying for. It is particularly attractive when residents arrive with full hands, wear gloves, or simply dislike touching a lock.
Consider another lock if you have no compatible Apple device, do not want Thread infrastructure, rent a property where replacing the deadbolt is prohibited, use a mortise, rim, interconnected, or double-cylinder lock, or mainly want an inexpensive fingerprint or PIN lock. A retrofit lock may be easier where preserving the existing deadbolt matters. A conventional Home Key lock may be better value if tapping a phone or watch is sufficient.
The total system cost is more than the lock alone if you need an Apple hub, Aqara hub, NFC cards, or professional installation. The U400’s premium is primarily for hands-free UWB entry—not simply for having many ways to unlock a door.
Bottom line
Aqara’s U400 is one of the first consumer smart locks to bring Apple’s UWB-based Unlock on Approach into a practical residential product. It genuinely moves beyond ordinary Home Key tap-to-unlock, but the experience depends on compatible devices, Thread and Apple Home infrastructure, correct installation, and a usable approach path.
Recommended Free Tools
For an Apple-focused household that values hands-free access, the U400 is a strong candidate. For everyone else—or for buyers who will mostly use a PIN, fingerprint, or tap—the lower complexity and price of a conventional smart lock may be the better construction and security decision.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
