Every smart lock promises you'll never dig for keys again. Then you're standing at the door with two grocery bags, waiting for Bluetooth to wake up, and you end up tapping the keypad anyway. The Aqara U400 is the first deadbolt built around that exact moment. It uses ultra-wideband, the same radio behind Apple's precision AirTag finding, to sense that you're walking toward the door and throw the bolt before your hand gets to the handle. This Aqara U400 review covers what that trick requires, the six other ways in when it doesn't apply, and whether the $270 asking price holds up against Schlage and Level.
What Is the Aqara U400 Smart Lock?
The U400 is a full single-cylinder deadbolt replacement, not a retrofit that bolts over your existing thumb-turn. Aqara announced it at CES in January 2026 and it has been shipping since February, so there's now eight months of owner feedback and long-term reviews to draw on.
The headline is UWB unlocking. With an iPhone 11 or later (not the SE or 16e) on iOS 18.5, or an Apple Watch Series 6 or later on watchOS 11.5, the lock measures your distance and direction and unlocks as you approach. It needs a Thread-capable Apple Home hub to do this: a HomePod mini, a second-generation HomePod, or a 2021 or 2022 Apple TV 4K.
Everything else is belt and suspenders. Apple Home Key lets you tap a phone or watch to the reader. A fingerprint sensor stores up to 50 prints and reads in roughly a third of a second, according to Aqara. The touchscreen keypad takes permanent, scheduled, and offline one-time codes. NFC cards (sold separately) work for kids, and two mechanical keys ship in the box.
Under the hood it's Matter over Thread, so the lock also shows up in Google Home, Alexa, SmartThings, and Home Assistant if that ecosystem has a Thread border router. Aqara calls it Aliro-enabled, meaning hands-free unlock for Android is promised through the cross-platform standard, with no date attached.
The battery is a removable rechargeable pack rated for up to six months, charged over USB-C from the inside, with an emergency USB-C port outside for a power bank. The exterior is IP65 rated, the bolt carries a BHMA Grade 3 certification, and a gyro sensor detects the door closing so auto-lock needs no separate sensor. It comes in black or silver.
Who Should Buy the Aqara U400?
The all-Apple household. If everyone carries an iPhone and a HomePod mini or Apple TV 4K already sits in the living room, this is the lock the platform has been waiting for. 9to5Mac's reviewer called it the first HomeKit lock that "truly delivers" on the set-it-and-forget-it promise, and long-term owners describe the same thing: the door is open by the time your hand lands.
The mixed household. One parent on iPhone, a teenager on Android, a dog walker twice a week. The U400 still works; the non-Apple people get fingerprint, keypad codes, or an NFC card instead of the walk-up unlock.
The Google or Alexa home. It functions through Matter over Thread, but you'd pay a premium for a UWB feature you can't use yet. Aqara's U200 or U100 make more sense there until Aliro ships on Android.
The security-first buyer or the renter. If forced-entry resistance is the reason you're shopping, look at a Grade 1 bolt like the Schlage Encode Plus. If you can't swap your landlord's deadbolt, the retrofit U200 keeps the existing cylinder.
Aqara U400 Features That Matter at the Door
- UWB approach unlock. The Home app lets you pick an approach direction (left, front, right, or all) so walking past on the way to the mailbox doesn't pop it open. Reviewers who logged their unlocks reported success rates between 95 and 99 percent, with the misses tied to a nearly dead iPhone.
- Home Key with Express Mode. Tap the phone or watch and the bolt moves, no Face ID prompt. Apple's power reserve keeps Express Mode working for a few hours after the iPhone shuts down from a flat battery, so a dead phone isn't a locked-out phone.
- Fingerprint and keypad as true backups. Fifty prints covers a big family. Offline one-time codes, up to eight per hour, let you hand a plumber a code even when your internet is down.
- Rechargeable battery with an escape hatch. Six months on paper, a pack you can charge on the kitchen counter, and an exterior USB-C port for emergencies. No more hunting for CR123A cells.
- Matter over Thread, no Wi-Fi radio. Thread sips power compared with Wi-Fi locks that chew through batteries, and local control doesn't depend on one vendor's cloud.
What You'll Pay for the Aqara U400
List price is $269.99, which puts the U400 in the upper-middle of connected deadbolts. It's about $100 more than Aqara's retrofit U200 and roughly $50 to $80 less than the Schlage Encode Plus and Level Lock Pro. What the extra $100 over the U200 buys is UWB, a stronger motor, and a full deadbolt with a keypad built in.
This is also a lock that goes on sale on a schedule. Deal trackers logged it around $220 during Prime Big Deal Days this week, and it dipped to similar territory during the spring and summer sales. As of this writing, Amazon's own listing shows a 30-day range of $219.99 to $269.99, with today's price sitting at the top of it. The price widget above shows where the current number lands against our tracked history, so if it's near list, a sale is a matter of waiting a few weeks.
Aqara U400 vs. Schlage Encode Plus and Level Lock Pro
Schlage Encode Plus ($319 to $349). The better buy if raw hardware matters more than convenience. It's an ANSI Grade 1 bolt with Schlage's reputation behind it, Wi-Fi is built in so there's no hub to buy, and it supports Home Key. It does not do UWB or Matter, and it eats batteries faster because of that Wi-Fi radio.
Level Lock Pro ($349). The pick if you want the lock to look like a lock. All the electronics hide inside the bolt itself, and it speaks Matter over Thread with Home Key support. You give up the fingerprint reader and keypad, and remote access needs Level's $79 bridge, so the real price is closer to $430.
Aqara U200 ($169.99). Same brand, same Home Key and fingerprint reader, but it clamps onto your existing deadbolt and skips UWB. The right answer for renters and Android homes.
If you're outfitting the whole entryway, the U400 pairs naturally with a camera doorbell. Our Ring Battery Doorbell (2nd gen) review covers the budget end of that. And if Matter is new to you, our SwitchBot Hub 3 review walks through what a Matter hub does and doesn't bring to a mixed-brand home.
One Thing to Consider Before You Buy
The feature you're paying for is Apple-only right now. Android owners get every other way in, but the walk-up unlock that justifies the price over the U200 doesn't exist for them until Aliro lands, and Aqara hasn't committed to a date.
A few smaller things repeat in owner feedback. The interior panel is big, about seven inches tall and nearly two inches deep, and Tom's Guide listed "a little bulky" as a con. Installation replaces the entire deadbolt and routes two thin connector wires through the door; 9to5Mac's reviewer needed about an hour for two doors and called the wires fragile. Setup bounces between the Home app and the Aqara app. And while Aqara rates the battery at six months, owners report four to six depending on how often UWB fires.
Aqara U400 FAQ
Q: Does the Aqara U400 work with Android phones? Partly. Fingerprint, keypad codes, NFC cards, and app control through Google Home or SmartThings all work from an Android home. The hands-free UWB unlock is Apple-only today. Aqara says it's Aliro-enabled, which is the standard that should bring UWB to Android, but no timeline has been announced.
Q: Do I need a hub for the Aqara U400? For the good parts, yes. UWB unlock, Home Key management, remote access, and automations all require a Thread-enabled Apple Home hub: a HomePod mini, a HomePod (2nd gen), or an Apple TV 4K from 2021 or 2022. Without one you get Bluetooth-only control in the Aqara app, plus fingerprint, keypad, and keys.
Q: How long does the Aqara U400 battery last? Aqara rates it at up to six months per charge; owners land between four and six depending on traffic. You get a low-battery alert at 20 percent, charging takes a few hours over USB-C, and the exterior USB-C port accepts a power bank if it dies while you're out.
Verdict: Buy It If You're in Apple's Ecosystem
If your household runs on iPhones and a HomePod mini or Apple TV already sits in the living room, buy it: nothing else in Apple Home does hands-free entry this well, and the backups are deep enough that you'll never be locked out. If you're on Android or you want the strongest bolt on the block, pay less for the U200 or more for the Schlage Encode Plus instead.
If the card above shows the price down near its sale level, that's the moment. At full list it's still a fair deal for an Apple household, just not an urgent one.
