Pros & Cons
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- Multiple unlocking methods
- UWB compatible
- Supports Matter over Thread
- Wide platform compatibility
- Works with Apple HomeKey
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- Lacks Wi-Fi
- Requires a Thread-enabled Matter controller
- NFC cards not included
Aqara Smart Lock U400 Specs
| App | Mobile |
| Connectivity | Bluetooth |
| Connectivity | Wi-Fi |
| Geofencing/Location Services | |
| Guest Access | |
| Installation | Exterior Escutcheon |
| Installation | Interior Escutcheon |
| Integrations | Matter |
| Tamper Alarm | |
| Touchpad |
Building on the solid foundation of the Smart Lock U100, Aqara's Smart Lock U400 offers more of the same but adds support for Matter, which means it’ll work with most home automation ecosystems, and Thread, a mesh networking protocol designed for devices such as cameras, sensors, and other battery-powered smart home products. It also supports Aliro and ultra-wideband (UWB) technology for hands-free unlocking via your phone. Its $269.99 cost is near the top end of the smart lock price range, but if new technology, HomeKey, and UWB support are among your top priorities, it’s money well spent. If you can increase your budget, the Matter-enabled Eufy FamiLock S3 Max ($399.99) doubles as a 2K video doorbell and can be found for around $299 if you shop around, so it remains our Editors’ Choice winner for premium smart locks.
Design: A Familiar Form Factor With Premium Materials and Weather Resistance
Available in black or silver finish, the U400 is a complete lock assembly that includes interior and exterior escutcheons, a deadbolt assembly, strike plates, mounting hardware, a rechargeable lithium-ion battery pack, a user guide, two keys, and drilling templates. It fits doors that are 1-3/8 to 2-1/8 inches thick, with a 1-1/2- or 2-1/8-inch bore hole diameter and a 2-3/8- or 2-3/4-inch backset.
The exterior escutcheon has an IP65 weather-resistant rating and measures 6.5 by 2.9 by 1.0 inches (HWD). It features a 12-button touch screen keypad and a biometric fingerprint scanner, with a keyway hidden behind a sliding panel. The bottom edge holds a speaker and a USB-C port for quick charging and powering the lock with a power supply if the battery runs out. Data and Wi-Fi cables extend from the back of the escutcheon.
The interior escutcheon measures 7.0 by 3.0 by 1.2 inches and has a thumbturn knob for manually locking and unlocking the door. A rechargeable lithium-ion battery pack sits behind a removable cover, along with programming (set) and reset buttons. The battery pack will last up to six months on a single charge, depending on usage.
Features: Matter, UWB, and NFC Support, But No Wi-Fi
The U400 can be unlocked using the keypad, the fingerprint reader, voice commands, and traditional keys. It has a Bluetooth radio for local access but lacks a Wi-Fi radio. Instead, it requires a compatible Thread-enabled Matter controller, such as an Apple HomePod, an Amazon Echo, a Google Nest Hub, or a SmartThings Hub, to add it to your home network and connect it with other devices. Once connected, the lock can be opened with Apple Home Key and Samsung Wallet Digital Home Key, and it offers hands-free unlocking when used with Apple iPhones or Apple Watches that support UWB. The U400 also supports NFC (Near Field Communication), but you’ll have to shell out $9.99 per NFC card, as they are not included in the box.
For comparison, the Eufy FamiLock S3 Max offers built-in Wi-Fi plus Bluetooth, and supports Matter as well as UWB auto-unlocking. As a less expensive alternative, the Ultraloq Bolt Fingerprint ($199.99) lacks UWB technology but still supports auto-unlocking via GPS and Bluetooth and works with all the most popular smart home platforms.
App Experience: Centralized Control, Automation, and Detailed User Management
The U400 uses the same Aqara mobile app (available for Android and iOS) as the U100 and the Camera Hub G5 Pro and appears in its own panel on the app’s home screen. Tap the panel to open a control screen that displays the current status (locked, unlocked, open, closed) and has tabs for connecting via Bluetooth or a Matter-controlled app. A Work Mode button lets you toggle between Bluetooth and Standard mode (connected via Matter).
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(Credit: Aqara/PCMag)Below the buttons are five panels. The One-Time Password panel lets you create a randomly generated single-use password (PIN code), and the User Management panel lets you add users, register fingerprints and NFC cards, and create user schedules. The Remote Periodic Password panel lets you create time-based access passwords remotely as long as the lock is connected to a Thread/Matter controller. The Logs panel opens a screen where you can view all lock activity, including alerts, lock and unlock actions, and lock jams. If you need to view the user guide or chat with a support tech, tap the Device Mastery Guide panel. At the very bottom of the home screen is a Hold To Lock/Hold To Unlock button that locks and unlocks the door.
(Credit: Aqara/PCMag)Tap the three dots in the upper-right corner to access settings where you can edit the lock name and the room where it is installed, adjust alert volume, enable Door Not Closed and Door Unlocked alerts, link the lock to other Aqara devices (an Aqara hub is needed for this), and set a lockout time for failed access attempts. Here, you can also enable Auto-Lock, Do Not Disturb mode (which mutes system sounds and lowers voice announcements), and Night Latch mode (which disables unlocking for all but the administrator with Bluetooth access).
Installation: Straightforward Setup With Guided App Pairing
The U400 is as quick and easy to install as any complete lock set. I started by installing the deadbolt assembly and attached the exterior escutcheon to the mounting plate using the provided bolts. I fed the data and Wi-Fi cables through the hole in the mounting plate, connected them to their respective ports on the interior escutcheon, and then attached the interior escutcheon to the mounting plate.
I downloaded the mobile app, created an account, and tapped Add Accessory on the Accessories screen. I tapped Scan Code and used my phone to scan the QR code located in the battery compartment, at which point the app immediately recognized the lock. I skipped the installation tutorial, pressed the Set button once, then gave the lock a name and assigned it a location, and it was immediately paired with the app. I followed the instructions to calibrate the lock and added it to my Amazon Alexa ecosystem using the Matter code. I then used the Alexa pairing code to add it to my Apple Home ecosystem.
Performance: Fast Response Times, Reliable Biometrics, and Seamless Automation Support
The U400 worked well in my tests. It responded instantly to Aqara, Alexa, and Apple Home app commands to lock and unlock the door, and the touch-screen keypad was well-lit and responsive. The fingerprint scanner never failed to open the door, and I had no trouble using Alexa and Siri voice commands to lock and unlock the door.
Home Key and UWB access worked as intended. I created an Alexa routine to have a TP-Link Tapo L535 bulb turn red when the lock was unlocked, and it worked flawlessly. Scheduled and one-time password access worked without issue.
Final Thoughts
(Credit: John R. Delaney)
Aqara Smart Lock U400
The Aqara Smart Lock U400 offers multiple ways to unlock your door and uses the latest technology to connect to most home automation platforms, but you’ll need a Thread-enabled Matter controller to do so.