The Aqara Smart Lock U400 revolutionizes door access with Ultra-Wideband technology, making it the first production smart lock to unlock automatically as you approach with your iPhone or Apple Watch. This innovative smart lock combines cutting-edge security features with multiple unlocking methods, delivering a seamless hands-free experience that eliminates the need for fumbling with keys, codes, or apps. Whether your hands are full, you're wearing gloves in winter, or navigating heavy rain, the U400 provides effortless entry without compromise.
Revolutionary UWB Unlocking Technology
The standout feature is its Ultra-Wideband (UWB) capability. This transforms your iPhone or Apple Watch into a proximity-based digital key. As you approach your door, the lock detects your position and unlock intent. It then unlocks automatically-no action needed from you. This hands-free approach changes how smart home access works. No codes, no biometric checks, no removing gloves in cold weather.
The UWB system works intelligently to prevent accidental unlocking-it only opens your door when it determines you're genuinely ready to enter, avoiding delayed or unintended openings. This precision means you experience true convenience without compromising security, as the lock understands context and intent rather than simply responding to proximity alone.
Multiple Entry Methods for Complete Flexibility
While the UWB feature offers hands-free convenience, the U400 provides nine distinct unlocking methods to accommodate different situations and preferences:
- Fingerprint recognition with capacity for 50 stored fingerprints
- Password entry with ordinary, one-time, and scheduled codes (6-10 digits)
- NFC and Apple Home Key tap-to-unlock functionality
- Traditional physical keys (two included)
- Voice control through Alexa or Google Assistant
- Remote unlock via Aqara or Apple Home apps
- Keypad access for guests and temporary visitors
- NFC card support (sold separately)
- Apple Wallet integration for seamless tap-to-unlock on iPhone or Apple Watch
The fingerprint reader is noteworthy. It offers fast recognition and secure biometric access. The lock stores 75 PIN codes. This lets you manage access for family, guests, and service providers. Children can have codes that expire after school. Guests get one-time codes for specific dates. Service providers can access only during business hours.
Smart Home Integration and Connectivity
The Aqara Smart Lock U400 integrates seamlessly with modern smart home ecosystems through multiple connectivity standards. It supports Matter over Thread, Bluetooth 5.2, NFC, and Ultra-Wideband, ensuring broad interoperability across major smart home platforms. The lock is natively compatible with Apple Home through Home Key, with planned support for the broader Aliro ecosystem.
Apple users get native integration that works smoothly. Thread connectivity creates a mesh network. Your lock stays connected to your home hub, even when WiFi is weak. This multi-protocol design protects your investment. As new smart home standards emerge, Matter compatibility keeps your lock compatible with future devices.
Integration with Aqara Home App provides centralized control alongside Apple Home, giving you flexibility in how you manage your smart lock. The lock works seamlessly with other Aqara products, allowing you to create automated routines-for example, unlocking the door automatically triggers your entrance lights to turn on and adjusts your thermostat to your preferred temperature.
Advanced Security Features and Certification
Security is paramount, and the U400 delivers comprehensive protection. The lock is BHMA-certified (Grade 1). It meets strict American standards for mechanical strength and reliability. The IP65 rating protects against dust and water. It works outdoors in any weather. Its rekeyable design lets you change the cylinder without replacing the whole lock.
The lock includes several intelligent security modes managed through the Aqara App:
- Auto Lock automatically secures your door when closed
- Night Latch Mode restricts unlocking to admins and physical keys only
- Do Not Disturb Mode silences general alerts while maintaining critical notifications
- Forced Entry Detection alerts you immediately to tampering attempts
- One-Time Passcode allows temporary access codes that work only once
The built-in gyro sensor detects when your door closes and locks automatically, eliminating the need for additional contact sensors. This intelligent design means your door is always secure-even if you forget to lock it manually.
Technical Specifications and Battery Performance
The lock uses rechargeable lithium-ion batteries. You get 7 months of use per charge. Standby mode extends this to 8 months. Recharging takes 6 hours via USB-C. The 10-inch dock cable lets you charge without removing the lock. A voice alert warns when battery drops below 20%.
The lock is 17.8 cm tall and 10.7 cm wide. It weighs 1,140 grams with batteries. The compact size fits standard deadbolts. You need iOS 18.5 or watchOS 11.5 for UWB features. The lock supports Bluetooth 5.2, Thread networking, and Matter 1.4.
The lock's energy-efficient design minimizes power draw even during continuous biometric scanning and app notifications, contributing to the extended battery life that makes it practical for everyday use without constant recharging.
Setup and Installation
Installation is designed for easy setup. It works with standard deadbolts. The package includes mounting plate, hardware, keys, diagram, and manual. Professional installation is recommended. DIY setup is possible with basic tools and experience.
Remove your existing deadbolt and install the Aqara mechanism. The mounting plate ensures correct alignment. Step-by-step instructions guide you to connect your Matter controller. Choose HomePod mini, Apple TV 4K, or HomePod 2nd generation. Bluetooth pairing takes under two minutes.
The lock works with Aqara cameras like the G5 Pro and G410 doorbell. View visitors and unlock through live video. This creates a smart home security system where your lock and cameras work together. Get doorbell alerts on your iPhone. Unlock remotely for delivery people.
Real-World Usage Scenarios
The Aqara Smart Lock U400 excels in diverse real-world situations, transforming everyday access challenges into seamless experiences:
- Hands-full grocery returns: Walk right in when carrying bags without setting them down or searching for keys
- Winter convenience: No more removing gloves to unlock or fumbling with keycodes in freezing temperatures
- Rainy weather: Avoid struggling with wet, slippery hands trying to use traditional locks or keypads
- Guest management: Share temporary codes for houseguests or service providers without physical key transfers
- Family safety: Ensure children can't leave doors unlocked while maintaining secure access control
- Accessibility support: Elderly or mobility-challenged users benefit from hands-free and biometric options
These scenarios highlight how the Smart Lock U400 transforms your home security from a daily friction point into a frictionless experience that works naturally with how people actually live.
Why Choose the Aqara Smart Lock U400
The Smart Lock U400 stands apart as the first production smart lock to deliver true hands-free access through Ultra-Wideband technology. Whether you value the convenience of automatic unlocking, the security of biometric access, or the flexibility of multiple entry methods, this lock delivers on multiple fronts. It's particularly ideal for users invested in the Apple ecosystem who want cutting-edge smart home capabilities without sacrificing security or reliability.
For those seeking a forward-thinking smart lock that combines innovation with proven security standards and extensive home automation integration, the Aqara Smart Lock U400 represents a significant leap forward in residential access control technology.