Aqara U300 vs U200 Lite vs U400: Which Smart Lock for Your Door?

Answer up front — Choose on power, unlock method and day-to-day use. The U300 gives you a keypad, a fingerprint reader and NFC on 4 × AA batteries with no rechargeable option. The U200 Lite is the simpler NFC retrofit on a rechargeable pack rated at roughly six months. The U400 is the most capable and the most conditional: its UWB hands-free unlock needs a select iPhone or Apple Watch and a Thread-enabled Apple home hub, so it is not a drop-in upgrade. And before any of them: Aqara publishes no door thickness for the U200 Lite, the U300 or the U400, which is the single most common reason a smart lock purchase fails.

Aqara's lock range has widened from a single dead bolt into a retrofit family with different power, radios and unlock philosophy. The differences are real. What has not kept pace is the published documentation — and the most consequential gap is the one nobody mentions at the point of sale.

So this comparison is built around three questions: where the power comes from, how each one lets you in, and what living with it looks like six months in.

The comparison

A note on the U100. We have left its row deliberately thin. It is the dead bolt at the simple end of Aqara's Malaysian lock range, but Aqara's published material that we can verify does not itemise its unlocking methods, power source or dimensions. We would rather show you a gap than fill it with a plausible guess. Ask us and we will confirm the current model directly.

One naming note: the Malaysian channel lists the middle model as "Aqara U200", while Aqara's own product page names the current retrofit model the Smart Lock U200 Lite. It is the Lite we describe throughout.

The specification Aqara does not publish

Aqara publishes no door thickness for the U200 Lite, the U300 or the U400. The figure is absent from every one of those spec tables. Aqara's FAQ pages for these products are JavaScript-only help-centre pages with no server-rendered text, so the number is not recoverable there either.

We are not going to fill that gap. Door thickness ranges quoted elsewhere often contradict each other, and we are not going to pick one and present it as fact, because if it is wrong the consequence is not a disappointed review — it is a lock coming back out of your door.

And a lock that does not fit the door is one of the most common failed purchases in this entire category. It is more common than a lock that malfunctions. Nobody returns a smart lock because the keypad felt slow; they return it because the retrofit body would not sit in the door they actually have.

So the practical instruction is short: before you order, confirm the door thickness, the door material and the lock's required clearance with us. We would rather have that conversation than sell you a lock.

Our smart lock installation across door types and do you actually need a smart lock articles cover the door side of this.

Power: the boring axis that decides it

Most comparisons lead with fingerprint versus UWB. In a Malaysian home, power decides more purchases than unlock method does.

The U300 runs on 4 × AA batteries and has no rechargeable option. It does have a USB-C emergency port rated 5 V — for powering the lock from outside when the cells are dead, not a charging input you use on a schedule.

The U200 Lite and the U400 both use a rechargeable Li-ion pack rated at roughly six months. The U400 charges in situ over USB-C and warns you at 20 %, so it tells you before it fails — a better ownership experience than swapping cells and wondering whether you remembered.

The trade is straightforward: if you would rather set a six-month reminder than remember to buy four AAs, the U300 is the wrong shape of product for you, however good the keypad is. And its published −30~55 °C outer rating is the widest of the three — though a retrofit body of 140 × 76 × 73.5 mm outside is not a small object for a terrace door.

In a household where someone else manages the property, the rechargeable locks also age better — nobody has to notice a set of flat cells before the door stops opening from the outside.

What the flagship actually gains

The U400 is the interesting product, and it is also the most conditional.

Aqara's own tagline for it: "Your phone becomes a digital key that unlocks the door as you approach, with no tapping or codes required." That is UWB — distance-measured rather than signal-strength-inferred, which is the right technology for a Malaysian terrace where the gate, porch and front door sit within a few metres of each other.

But read the requirement carefully before you fall for it:

• UWB unlock requires a select iPhone or Apple Watch, and
• a Thread-enabled Apple home hub — HomePod mini or Apple TV 4K.

That is a second purchase, from a different company, to use a feature on a lock you just bought. If your household is entirely Apple, the experience is the best available. If anyone is on Android, they still need a PIN or a card, exactly as on a U300.

What else the U400 brings: Aliro, the credential standard, so more ecosystems are expected to follow it than Thread currently has; a Samsung Wallet key via SmartThings; 50 stored fingerprints with a stated 98.6 % recognition rate; and rechargeable power with a 20 % warning. Its DL-D06D and DL-D16D bundles include a Hub M100, which matters if you do not already run an Aqara hub — the M100 is a Matter Controller and a Thread Border Router, which is what a Thread lock needs.

One honest note: Aqara's U400 spec table omits the wireless protocol list entirely. It says Matter over Thread in the surrounding text. We are not going to fill in a column the manufacturer did not publish.

The ecosystem catches nobody mentions

The U200 Lite's quiet mode, gyro auto-lock and timed auto-lock are all disabled by default, and available in Aqara Home only. That is a real limitation for anyone running Home Assistant or bridging into another platform, and it is the kind of thing that surfaces two months after installation.

Two more conditions worth knowing before you buy a Thread-based lock:

1. A Matter ecosystem needs both a Matter Controller and a Thread Border Router. They are not always the same box, and Aqara's hubs are not interchangeable here. The M100, M200 and M3 are all Controller plus Thread Border Router. The M2 is a Matter Bridge only and has no Thread radio at all — it is the wrong hub for a Thread lock, full stop.
2. The U100 is Zigbee 3.0, the older radio. Fine and stable, but a different ecosystem from the Thread generation, and a Zigbee lock will not be brought into Matter as a Thread device by any firmware.

If that distinction matters to your plan, Zigbee, Wi-Fi or Matter: choosing a hub and Matter with Aqara: what needs a Matter Controller cover it properly.

Channel and support path

Buying through the Malaysian channel matters for one practical reason. A unit sourced outside it may not pair to your region cleanly, and there is no local party with a reason to help on the day something does not work. Confirm the exact model and its local support with us before you order.

A smart lock manages access. It does not make a weak door strong.

A smart lock is a key management device. Its job is to let the people who live in your house come and go without a keyring, and to let you revoke someone's access without calling a locksmith. It does that well.

It adds nothing to a terrace where the gate is low, there is a gap under the fence, the door leaf warps in the monsoon and no longer closes on the latch, or someone can stand unseen beside the porch. A fingerprint reader does not make a hollow-core door solid. It makes the front door convenient while the actual weak point stays exactly where it was.

If your concern is security, the money belongs on the gate, the frame and the alignment of the leaf. If your concern is convenience — an elderly parent, a helper, a contractor, keys lost twice this year — then a smart lock is solving a real problem, and which one you want turns on batteries versus rechargeable, keypad versus card, and whether your household is all-Apple.

What this page does not claim

• No door thickness, for any lock on this page. Aqara does not publish one and neither will we.
• No confirmed Malaysian channel availability for the U400. Confirm with us.
• No battery life figure for the U300, because Aqara publishes none.
• No guarantee that any lock fits your door. Nothing here replaces measuring it.
• No warranty duration, no return window, no service commitment. Ask us about a specific unit.