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Aqara Smart Lock U400 vs Eufy FamiLock S3 Max

Full Smart Door Locks comparison in 2026

Updated June 2026
Data from Amazon and official Aqara and Eufy sites.
2026 verdict
Between Aqara Smart Lock U400 and Eufy FamiLock S3 Max, Aqara Smart Lock U400 is the better overall pick in 2026, leading on price, battery life, and connectivity. What pushes it ahead is price, battery life, and connectivity, and lock/unlock system and one-time password keeps the advantage from looking narrow. Eufy FamiLock S3 Max remains a niche alternative if rating and doorbell matters more than the rest of the comparison. As a general recommendation, Aqara Smart Lock U400 comes out on top.
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FeatureAqara Smart Lock U400Eufy FamiLock S3 MaxWinner
Price$219.99$279.98Aqara Smart Lock U400
Rating4.24.4Eufy FamiLock S3 Max
Battery Life6 months4 monthsAqara Smart Lock U400
ConnectivityBluetooth, Thread Protocol, Other2.4 GHz WiFiAqara Smart Lock U400
Lock/Unlock SystemRemote, Bluetooth, Passcode, Fingerprint, NFC Tag, Apple Home Key, Physical KeyRemote, Passcode, Physical KeyAqara Smart Lock U400
One-Time PasswordYESNOAqara Smart Lock U400
Periodic PasswordYESNOAqara Smart Lock U400
DoorbellNOYESEufy FamiLock S3 Max
Weather ResistanceIP65IP65Tie
IntegrationsGoogle Home, Alexa, Apple HomeKit, Home Assistant, MatterGoogle Home, Alexa, Apple HomeKit, Samsung SmartThings, MatterTie
Anti-peep PasswordNONOTie
Emergency FingerprintNONOTie

Frequently Asked Questions (FAQ)

Which is better overall: Aqara Smart Lock U400 or Eufy FamiLock S3 Max?
Aqara Smart Lock U400 has the stronger overall profile in this comparison, especially for price, battery life, and connectivity.
What is the biggest difference between Aqara Smart Lock U400 and Eufy FamiLock S3 Max?
Price is one of the clearest differences: Aqara Smart Lock U400 lists $219.99, while Eufy FamiLock S3 Max lists $279.98.
Which one looks better on price?
Aqara Smart Lock U400 is listed at $219.99, while Eufy FamiLock S3 Max is listed at $279.98. Aqara Smart Lock U400 (better spec).
Who should buy Aqara Smart Lock U400?
Choose Aqara Smart Lock U400 if your priority is price and battery life and that matters more than rating.
Who should buy Eufy FamiLock S3 Max?
Choose Eufy FamiLock S3 Max if your priority is rating and doorbell and that matters more than price.
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