I tried out Apple’s hands-free Home Key, and it’s a significant improvement.

Aqara has unveiled its latest smart deadbolt lock, the U400, at CES this week. Priced at $269.99, this lock is the first to integrate with Apple’s Home Key for hands-free unlocking. Utilizing the U1 ultra-wideband (UWB) chip found in many iPhones and Apple Watches, the U400 can automatically unlock your door as you approach, eliminating the need for any physical interaction. I had the chance to test the U400 at home earlier this month, and it has significantly improved my front door access.

While I still need to physically open the door, I no longer have to enter a code, use a fingerprint, or even pull out my phone or watch; the door unlocks as I arrive. This feature is a game-changer, especially when my hands are full, I’m wearing gloves, or I’m simply in a rush.

Hands-free unlocking isn’t a new concept; I’ve tried various proprietary systems from brands like Yale, August, and Level. However, the technology behind the U400 sets it apart. Most existing systems rely on a combination of Bluetooth, Wi-Fi, and geofencing, requiring an app to be active on your phone. I’ve often found these systems unreliable, leaving me waiting in front of a locked door.

Apple’s approach combines Bluetooth and UWB to create a direct connection between the lock and your phone, eliminating the need for an app. During my week of testing, it worked flawlessly every time, except for one instance when my phone was under a pizza box. It still unlocked, but there was a slight delay.

UWB-supported Apple devices compatible with Home Key’s hands-free unlocking include:
* iPhone 11 and later (excluding iPhone SE 2nd and 3rd generation and iPhone 16e) running iOS 18.5 or later
* Apple Watch Series 6 and later (excluding Apple Watch SE) running watchOS 11.5 or later

UWB is a low-power, short-range technology that uses brief pulses across a wide frequency band, designed for secure, real-time location and distance measurements. It’s already popular for unlocking cars and is precise enough to determine your approach angle, ensuring it won’t unlock if you’re inside the house or just passing by.

UWB unlocking is part of Apple Home Key, a feature that allows you to use your iPhone or Apple Watch as a key with compatible smart locks. While NFC tap-to-unlock Home Key locks have been available since 2022, UWB unlocking was introduced with iOS 18 in 2024, and the U400 is the first lock to support it.

Expect to see more locks adopting this technology soon. UWB is part of a new universal smart lock standard called Aliro, developed by Apple, Samsung, Google, and major lock manufacturers. Aliro aims to bring both UWB and NFC unlocking to various smart home platforms and devices beyond Apple, including Samsung Galaxy and Google Pixel devices. The U400 is ready for Aliro, which was announced in 2023 and is set to launch this year.

Last year at CES, a few UWB locks were announced, including models from Schlage and U-tec, but Aqara’s U400 is the first to confirm compatibility with Apple’s Home Key.

The U400 is a full-replacement deadbolt smart lock that can be unlocked via Home Key (NFC or UWB), a code on its touchscreen keypad, a fingerprint reader, or a traditional key. It operates on Matter-over-Thread, allowing control through any Matter-compatible smart home app, and it can also be managed via Aqara’s app using Bluetooth.

Specs for the Aqara U400 include:
* Price: $269.99
* Connectivity: Bluetooth 5.2, Thread (Matter 1.4), NFC, and UWB
* Weatherproof rating: IP65
* Colors: Silver, black, satin nickel, shadow black
* Dimensions: Inner panel: 7.01 × 2.99 × 1.85 inches / Outer panel: 6.58 × 2.99 × 1.01 inches
* Power: Battery-powered; 4,880mAh rechargeable Li-ion battery
* Battery life: Up to six months
* Battery backup: Exterior USB-C charging port
* Security rating: BHMA Grade 3 Certified
* Replaceable cylinder: Yes

The U400 features a built-in gyroscope to detect whether the door is open or closed and can be set to lock automatically when closed. It’s IP65-rated and comes with a single 4,880mAh rechargeable battery, which Aqara claims will last six months on a single charge. While this is on the lower end for a Thread-powered lock, UWB does consume more power.

Installation and setup of the U400 were straightforward, similar to most smart locks, with the addition of a second data cable for powering the UWB radio and antenna. The lock is larger and taller than Aqara’s other models, likely to accommodate the extra technology.

I tested the silver version, and like many of Aqara’s devices, it prioritizes functionality over aesthetics. The Aqara logo at the bottom isn’t my favorite feature, and the large black touchscreen quickly showed fingerprints. The exterior is aluminum and feels solid, but the rear housing is primarily plastic.

I connected the lock to the Apple Home app by scanning the Matter code, and the onboarding process was smooth (a Thread border router is required). With Home Key already set up, Apple Home prompted me to use it with the U400 and activate Express Mode.

This mode allows for unlocking without needing Face or Touch ID, which is essential for hands-free operation. While the U400 unlocks via UWB, it first connects to your phone through Bluetooth. Interestingly, the lock maintained its Bluetooth connection whenever I was inside the house.

Since Home Key works for all members of my Apple Home household, my family’s iPhones were automatically updated to work with the U400. However, I had to enable Express Mode on each phone individually in the Home app and activate Unlock on Approach in their Apple Wallet for hands-free unlocking to function.

You can add access codes through Apple Home, and the touchscreen keypad is responsive and user-friendly. Its large size means the numbers are well spaced, making it easy to input the correct codes.

If you connect the lock to the Aqara app, you can also add codes and fingerprints. The fingerprint reader is quick and responsive, serving as a reliable backup when you don’t have your phone handy.

I’ve been eager for UWB hands-free unlocking, and based on my experience, Aqara’s U400 delivers a seamless, secure, and speedy way to access your home. While the lock is bulkier and less refined than some other smart locks, the reliability and speed of Home Key UWB provide an exciting glimpse into the future of smart locking technology.