Is the Internet’s Favorite Smart Lock Worth It? – Aqara U400 Review

By Josh Teder

It’s been 6 months since I got an Aqara U400 smart lock, which you’ll see many online argue is the best smart lock that you can buy right now.

Ultra-Wideband Unlocking and Home Key

The first thing that has stood out with this lock, and probably its best feature, is the ultra-wideband unlocking technology. What this allows you to do is walk up towards the lock, and it’ll automatically connect to your phone or your smartwatch and then unlock by the time you get to the door.

It feels like magic, and it’s especially useful when you’ve got your hands full.

For all of my testing period, this feature has been an Apple-exclusive feature called Home Key Express Mode. Apple has just been far and ahead of everybody else in the smart lock game. But later this year, Google and Samsung are expected to roll out the ultra-wideband unlocking experience. If you want to understand more about where this technology is headed, I’ve written more about the Aliro standard and what it means for smart locks in 2026.

How It Performs

So, okay, that’s a really cool feature, but how well does it really work, you might ask? Actually, it’s worked pretty reliably for me over the past 6 months. Nine times out of 10, it does it without issue. And that 10th time, you’ll just walk up to the lock and nothing happens. But that’s been more of a rarity. And because I’m wearing an Apple Watch anyway most of the time, it’s not that big of a deal, since tapping my watch on the lock will also unlock it.

That’s using an Apple feature called Home Key, which stores a digital key on your iPhone or Apple Watch and uses a technology called near-field communication, or NFC, to enable the tap-to-unlock-and-lock experience. That feature has worked flawlessly. I can’t recall a single failure with Home Key over the past 6 months. Towards the end of my 6-month period, Samsung actually rolled out their own tap-to-unlock version of Home Key.

Backup Unlock Options

But what if you have a phone like the Pixel that, at the time of recording, doesn’t have a similar feature to Home Key Express Mode or tap-to-unlock? Aqara thought of that with its built-in fingerprint sensor, which has also worked reliably over the past 6 months. That’s the main way my husband has been using this lock, and it’s worked pretty well for him.

Besides a fingerprint, there are also key codes that you can program per user, as well as for guests. And if all else fails, Aqara also included a physical key backup. This differentiates Aqara’s lock from competitors like Schlage’s new Sense Pro, which doesn’t actually have a keyhole. If that lock dies, you need to jump-start it via a USB-C cord.

Design and Battery Life

Another highlight I wanted to mention, and this one is a bit more subjective, but as far as smart locks go, I think, given how much Aqara actually built into this lock, it looks pretty nice. You can get it in two colors, black and silver. There’s also a more premium Deluxe version, available through both Apple and Samsung, which you can find on the featured products list below.

The last highlight with this lock is battery life. It can last up to 6 months on a single charge, and in my 6 months of testing, that has been accurate. I haven’t had to charge it at all during my testing period, which is pretty impressive, given this lock is unlocked and locked at various times throughout the day. I put it on our garage door, which is by far the most-used door in the entire home, and at the end of my review period, it’s sitting at 27% remaining.

Part of the reason for that great battery life is that this lock runs on Matter over Thread. I’m not going to get into everything about Thread in this post. You can check out my explainer and smart home guide for 2026, which goes more into detail on Thread and what you need to know. But in general, Thread offers much better battery life than Wi-Fi locks.

The Aqara App and Smart Home Integration

Now, not everything is great with this lock. But before I get into downsides, I do want to point out something that I didn’t end up using all that much, which is Aqara’s app.

With this lock, you do need the app to initially set it up, add additional users, register fingerprints, update the firmware, and configure the gyro auto-lock. But once that’s done, you can actually check its battery level, set additional passcodes, and configure things like Home Key Express Mode approach directions directly from the Apple Home app, or some functions from an app like Google Home. Because the U400 supports Matter over Thread, any smart home platform that supports Matter and Thread should be able to bring the lock right in.

Downsides

Now let’s look at the downsides I’ve actually encountered. The biggest one, by far, has been the automatic locking feature. This lock uses an integrated gyroscope to detect when the door closes and then automatically throws the deadbolt. The problem is that, on occasion, especially if you prop open the door for long periods of time when you’re moving stuff in and out, I found this feature can fail, causing the lock to stick the deadbolt out while you’re closing the door, which has caused damage to the wood trim around it.

The other downside I’ve run into is I do think the setup experience could be an issue for some. When you buy this lock, if you don’t have technical knowledge about how Matter over Thread actually works, you’ll see a confusing message in the app about needing an Aqara hub to make the lock work, and you might go out and buy it when, in reality, you probably don’t need to.

You need the Aqara hub only if you plan to use the Aqara app to control the lock and change its settings when the lock isn’t in Bluetooth range of your phone. However, if you plan to use another smart home platform like Apple Home, Home Assistant, or Google Home to control the lock and view its status, as long as you have a device from your chosen platform that can act as a Thread border router (like an Apple TV or HomePod for Apple Home, or a Nest Hub for Google Home), you don’t really need the Aqara hub.

There’s also another part of the Matter learning curve: knowing that, once you set up a device in Apple Home, for example, you can put it in pairing mode, copy a code, and then paste it into Google Home to make the lock show up there as well, without having to manually set the lock up again from scratch.

Reliability

How has the reliability been with this smart lock and the smart home platforms I’ve tried it with? Overall, actually pretty great. I only had one time where it dropped out of one of my smart home platforms entirely, which was right at the start of my review period. I think this may have just been a bug, because I did eventually get it to work, and in the months since, I haven’t had a single issue.

Price and Is the Aqara U400 the Best Smart Lock?

So, do I recommend getting this lock? Yes, and I’ve genuinely enjoyed using it. But that still leaves the bigger question: is this actually the best smart lock to get right now? It’s been 6 months since it launched, and other locks have begun to enter the market with similar technology, which leads me to the last thing I haven’t talked about yet: price.

The Aqara U400 retails for $270, making it less expensive than both of its main competitors, the Schlage Sense Pro and the Ultraloq Bolt Mission UWB.

Feature	Aqara U400	Schlage Sense Pro	Ultraloq Bolt Mission UWB
Price	$270	$399	Check current price
Ultra-wideband unlocking	Yes (Apple Home Key Express Mode)	Yes (Apple HomeKey Express, Schlage Converge)	Yes (Ultraloq app only, no Home Key Express Mode support)
Fingerprint sensor	Yes	No	No
Physical keyhole backup	Yes	No (USB-C jump-start only)	Yes
Warranty	1 year standard	3 years on electronics, lifetime on mechanical and finish	—
Security grade	BHMA/ANSI Grade 3	BHMA/ANSI Grade 2	—

So, given the price, is Aqara the best? Well, yes, it’s less expensive. It’s the only one of these with a fingerprint sensor, which does matter to those who don’t have phones or smartwatches with ultra-wideband unlocking tech or tap-to-unlock. It’s way more convenient than a passcode. Plus, when you look at the competitors, the Schlage has no keyhole at all, so there’s no real backup way to unlock it outside of that USB-C jump-start. It does have a better warranty, so that’s something in its favor. The U400 only has a one-year standard warranty.

The U400 and Sense Pro, for that matter, also both look nicer than the Ultraloq, which is totally a subjective take, but I just think the Ultraloq looks ugly. And while it has ultra-wideband unlocking, that’s only supported using Ultraloq’s own app, not Home Key Express Mode. I don’t understand the appeal of that lock at all.

The only other thing Schlage has going for it, potentially, is its build quality and security grade. The U400 is a BHMA/ANSI Grade 3 lock, while the Schlage Sense Pro is Grade 2, so you get a slightly higher build quality and security compared to the Aqara lock. But that’s actually a step below the Grade 1 rating you get on most of Schlage’s other smart locks, which is a bit puzzling.

Given all of that, for most people, I think you’d be fine with an Aqara U400. The area where I’d personally be a bit more picky is if you have a door that opens to a high-traffic area, or you’re in an area with a lot of break-ins or other security concerns. That’s where I’d personally want a better lock grade and would likely opt for a higher-rated smart lock.

Final Verdict

So, is the Aqara U400 really the best smart lock you can get right now? For most people, yeah.

For most people, I think you’d be fine with an Aqara U400.

It packs in UWB unlocking, Home Key Express Mode, a fingerprint sensor, great battery life, and Matter over Thread support, and has the most competitive price among its competition.

Those are all of my thoughts on the Aqara U400 smart lock. For more of my smart home coverage, check out my Smart Home Guide 2026, or head over to the 6 Months Later homepage for content and updates on the tech we cover.