Door Locks · Head to head

Aqara Smart Lock U400 vs Eufy FamiLock S3

Full Smart Door Locks comparison in 2026

Updated August 2026
Data from Amazon and official Aqara and Eufy sites.
2026 verdict
Aqara Smart Lock U400 has the better all-around case than Eufy FamiLock S3 in 2026, starting with price, battery life, and connectivity. It builds its lead on price, battery life, and connectivity, then backs it up with a stronger showing on Lock/Unlock system. The only strong reason to choose Eufy FamiLock S3 is if rating, integrations, and doorbell are more important to you than the overall verdict. That is why the final call still favors Aqara Smart Lock U400.
vs
FeatureAqara Smart Lock U400Eufy FamiLock S3Winner
Price$269.99$299.99Aqara Smart Lock U400
Rating4.04.1Eufy FamiLock S3
Battery Life6 months4 monthsAqara Smart Lock U400
ConnectivityBluetooth, Thread Protocol, Other2.4 GHz WiFiAqara Smart Lock U400
IntegrationsGoogle Home, Alexa, Apple HomeKit, Home Assistant, MatterGoogle Home, Alexa, Apple HomeKit, Samsung SmartThings, Home Assistant, MatterEufy FamiLock S3
Lock/Unlock SystemRemote, Bluetooth, Passcode, Fingerprint, NFC Tag, Apple Home Key, Physical KeyRemote, Passcode, Physical KeyAqara Smart Lock U400
DoorbellNOYESEufy FamiLock S3
Weather ResistanceIP65IP65Tie
One-Time PasswordYESYESTie
Periodic PasswordYESYESTie
Anti-peep PasswordYESYESTie
Emergency FingerprintNONOTie

Frequently Asked Questions

Which is better overall: Aqara Smart Lock U400 or Eufy FamiLock S3?

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?

Price is one of the clearest differences: Aqara Smart Lock U400 lists $269.99, while Eufy FamiLock S3 lists $299.99.

Which one looks better on price?

Aqara Smart Lock U400 is listed at $269.99, while Eufy FamiLock S3 is listed at $299.99. 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?

Choose Eufy FamiLock S3 if your priority is rating and integrations and that matters more than price.

More Door Locks

Top Door Locks to compare next

Compare the best smart door locks by unlock methods, connectivity, battery life, integrations, security alerts, and more. Find the right lock for your home.

Compare Door Locks
Aqara

More Aqara products

A sharper look at other Aqara products worth comparing.

Explore Aqara
Eufy

More Eufy products

A sharper look at other Eufy products worth comparing.

Explore Eufy
Stay in the loop

Smart Home Deals & News straight to your inbox

Join the newsletter and get the best smart home deals and new releases in your inbox.

Your subscription could not be saved. Please try again.
Your subscription has been successful.

Smart Home Deals & News straight to your inbox

Join the newsletter and get the best smart home deals and new releases in your inbox.

Independent · Not sponsoredBrands never pay for placement or rankings. Affiliate commissions never influence our comparisons.
© 2026 Smart Home Compared
Search