Winner
Updated November 2026
Data from the official Aqara and Eufy sites.
2026 verdict
If the lock's job is to open the door and open it well, the Aqara Smart Lock U400 is the better choice of these two, with a fingerprint reader, NFC, Apple Home Key and a longer battery life.
It is also the more affordable and connects over Matter and Thread rather than Wi-Fi. The Eufy FamiLock S3 Max is a different kind of product: a lock with a 2K doorbell camera, night vision, local video storage and a rear screen that works as a digital peephole. Both list Matter, Apple Home, Google Home, Alexa, SmartThings and Home Assistant support and IP65 weather resistance. Buy the Aqara Smart Lock U400 for fast, keyless entry, and the Eufy FamiLock S3 Max only if you want the camera and screen built into the door.
vs
10% OFF
$359.99
$399.99
Connectivity
- Wi-Fi 2.4 GHz
News by email
Still comparing? Get what's new by email
New releases and the smart home news worth knowing, in your inbox.
No spam. Unsubscribe in one click.
| Feature | Aqara Smart Lock U400 | Eufy FamiLock S3 Max | Winner |
|---|---|---|---|
| Price | $269.99 | $359.99 | Aqara Smart Lock U400 |
| Rating | 4.1 | 4.3 | Eufy FamiLock S3 Max |
| Battery Life | 6 months | 4 months | Aqara Smart Lock U400 |
| Connectivity | Bluetooth, Thread Protocol, Other | 2.4 GHz WiFi | Aqara Smart Lock U400 |
| Lock/Unlock System | Remote, Bluetooth, Passcode, Fingerprint, NFC Tag, Apple Home Key, Physical Key | Remote, Passcode, Physical Key | Aqara Smart Lock U400 |
| Doorbell | NO | YES | Eufy FamiLock S3 Max |
| Weather Resistance | IP65 | IP65 | Tie |
| Integrations | Google Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter | Google Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter | Tie |
| One-Time Password | YES | YES | Tie |
| Periodic Password | YES | YES | Tie |
| Anti-peep Password | YES | YES | Tie |
| Emergency Fingerprint | NO | NO | Tie |
What the differences mean
Camera and doorbell
The Eufy FamiLock S3 Max has a 2K camera with night vision, motion detection, internal storage and a doorbell, plus an indoor screen. The Aqara Smart Lock U400 has no camera and no doorbell, so it is only a lock.
Ways to unlock
The Aqara Smart Lock U400 lists a fingerprint reader, passcode, NFC, Apple Home Key, Bluetooth and a physical key, with ultra-wideband unlocking as you approach. The Eufy FamiLock S3 Max lists a passcode and physical key, with palm-vein unlocking described by its owners, and no NFC or Apple Home Key.
Connection and platforms
The Aqara Smart Lock U400 uses Bluetooth and needs a Thread border router, while the Eufy FamiLock S3 Max uses 2.4 GHz Wi-Fi. Both list Matter, Apple Home, Google Home, Alexa, SmartThings and Home Assistant.
Battery
The Aqara Smart Lock U400 has a built-in rechargeable battery rated about 6 months with a USB-C emergency port. The Eufy FamiLock S3 Max is rated about 4 months and falls back on 4 AAA cells.
Which one to buy if
- you use an iPhone or Apple Watch and want the door to unlock as you walk up
The Aqara Smart Lock U400 adds ultra-wideband hands-free unlocking and Apple Home Key.
- you want a video doorbell and a peephole screen built into the lock
The Eufy FamiLock S3 Max has the 2K camera, doorbell and indoor screen the Aqara Smart Lock U400 lacks.
- you would rather not depend on Wi-Fi for the lock
The Aqara Smart Lock U400 runs on Bluetooth and Thread, while the Eufy FamiLock S3 Max relies on 2.4 GHz Wi-Fi that some owners find unstable.
- you want video stored locally with no subscription
The Eufy FamiLock S3 Max keeps recordings on internal storage.
Winner
$269.99
- + Price: $269.99
- + Battery Life: 6 months
- + Connectivity: Bluetooth, Thread Protocol, Other
- - Rating: 4.1 vs 4.3
- - Doorbell: NO vs YES
10% OFF
$359.99
$399.99
- + Rating: 4.3
- + Doorbell: YES
- - Price: $359.99 vs $269.99
- - Battery Life: 4 months vs 6 months
What owners say
Owners of both locks are impressed by a headline feature. Aqara Smart Lock U400 owners rave about hands-free ultra-wideband unlocking that opens the door as they approach with an iPhone or Apple Watch, a motor they call two to three times faster than a Schlage or Yale and a rechargeable USB-C battery, while they mention a plasticky housing, confusing HomeKit and Thread setup and newness. Eufy FamiLock S3 Max owners praise how one device does lock, doorbell, camera and digital peephole, a palm-vein reader that works in the rain and video kept on local storage with no monthly fee. Their complaints are unstable Wi-Fi or HomeBase connections, Matter that works for some and errors out for others, slow charging and cold-weather battery drain and slow customer support.
Frequently Asked Questions
Which is better overall: Aqara Smart Lock U400 or Eufy FamiLock S3 Max?
The Aqara Smart Lock U400 as a lock: more ways to unlock, a longer battery life, a lower price and Thread connectivity. The Eufy FamiLock S3 Max is the choice only if you want a camera and doorbell in the same device.
What is the biggest difference between the Aqara Smart Lock U400 and the Eufy FamiLock S3 Max?
The camera. The Eufy FamiLock S3 Max adds a 2K doorbell camera, night vision, local storage and an indoor screen, while the Aqara Smart Lock U400 is a lock with no video.
Do the Aqara Smart Lock U400 and the Eufy FamiLock S3 Max support Matter?
Yes, both list Matter, along with Apple Home, Google Home, Alexa, SmartThings and Home Assistant. The Aqara Smart Lock U400 needs a Thread border router and the Eufy FamiLock S3 Max uses Wi-Fi.
Does the Aqara Smart Lock U400 or the Eufy FamiLock S3 Max support Apple Home Key?
The Aqara Smart Lock U400 does, together with NFC. The Eufy FamiLock S3 Max lists neither Apple Home Key nor NFC.
Who should buy the Aqara Smart Lock U400?
Apple households that want hands-free ultra-wideband unlocking, a fast motor, a rechargeable battery and Matter over Thread, and can live with a plasticky housing.
Who should buy the Eufy FamiLock S3 Max?
Buyers who want a lock, doorbell camera and digital peephole in one device with local video storage, and who have reliable 2.4 GHz Wi-Fi at the door.
Spotted something wrong on this page? Tell us and we will fix it.
Our store on AmazonShop our ideas on AmazonLists of the smart home setups we would put together ourselves, ready to add to your Amazon cart.Shop on AmazonFull comparison table
Compare all 59 Door Locks side by side
You are looking at two of them. The full table lines up all Door Locks in the catalog with the same specs, so you can filter by what you need and sort by price or rating.
- 59 Door Locks
- 56 specs compared
- 52 filters
- Door Locks
FamiLock E32
- Door Locks
Palm Lock
- Door Locks
FamiLock E40
- Door Locks
Smart Lock Ultra
- Door Locks
Auto-Lock Bolt v2
- Door Locks
Tapo DL105
- Door Locks
Tapo DL130
- Door Locks
4200 Series Smart Deadbolt with Door Lever
- Door Locks
SwitchBot Lock Ultra Vision Combo
- Door Locks
Tapo DL100
- Door Locks
Smart Lock C32
- Door Locks
Lock Vision
- Door Locks
Encode
- Door Locks
Bolt SE
- Door Locks
Smart Lock Pro
- Door Locks
Wi-Fi Smart Deadbolt DDL242X
- Door Locks
Arrive
- Door Locks
U-Bolt Pro WiFi
- Door Locks
Smart Lock C220
- Door Locks
Nest x Yale Lock
- Air Quality Monitors
TVOC Air Quality Monitor
- Buttons
Cube T1 Pro
- Buttons
Wireless Mini Switch T1
- Buttons
Wireless Mini Switch WXKG11LM
- Cameras
Camera E1
- Cameras
Camera G100
- Cameras
Camera Hub G2H Pro
- Cameras
Camera Hub G3
- Cameras
Camera Hub G350
- Cameras
Camera Hub G5 Pro PoE
- Cameras
Camera Hub G5 Pro WiFi
- Ceiling Lights
Ceiling Light T1M
- Doorbells
Doorbell Camera G400 (Wired)
- Doorbells
Doorbell Camera Hub G410
- Doorbells
Smart Video Doorbell G4
- Door Locks
Smart Lock D200i
- Door Locks
Smart Lock N100 Zigbee Edition
- Door Locks
Smart Lock U100
- Door Locks
Smart Lock U200
- Door Locks
Smart Lock U300
- Cameras
4G Camera S230
- Cameras
4G LTE Cam S330
- Cameras
Cam S3 Pro
- Cameras
Cam S330
- Cameras
Cam S4
- Cameras
eufyCam C35
- Cameras
eufyCam C37
- Cameras
Indoor Cam C120
- Cameras
Indoor Cam E220
- Cameras
Indoor Cam E30
- Cameras
Indoor Cam S350
- Cameras
Outdoor Cam E210
- Cameras
Outdoor Cam E220
- Cameras
PoE Bullet-PTZ Cam E50
- Cameras
SoloCam E30
- Cameras
SoloCam E42
- Cameras
SoloCam E50 (S340 Next-Gen)
- Cameras
SoloCam S220
- Cameras
SoloCam S230
- Cameras
SoloCam S340