Best Retrofit Smart Locks for Renters & Homeowners 2026

August's Wi-Fi Smart Lock remains the single most reviewed retrofit smart lock on Amazon, and its reputation is thoroughly deserved. Installation takes approximately 10–20 minutes with only a screwdriver: remove the interior thumb-turn, attach August's baseplate, slide the lock on — your exterior deadbolt and key cylinder remain 100% unchanged. The 4th-gen model added built-in Wi-Fi, eliminating the need for the separate Connect bridge. Full remote access, auto-unlock geofencing, access log, unlimited virtual guest keys, and compatibility with Alexa, Google Assistant, and Apple HomeKit make this as feature-complete as any full-replacement smart lock.

The Bluetooth-only August Smart Lock offers the same acclaimed retrofit installation at a $60 lower price than the Wi-Fi model. For those who primarily lock and unlock while physically present, this is the ideal entry point. The August app over Bluetooth enables auto-unlock when you arrive, access sharing with guests, and door open/close status monitoring. The entire exterior of your door is untouched: same keyhole, same deadbolt, same key. Guest access can be time-limited and revoked remotely.

The Aqara U200 is the premium retrofit lock of 2026, combining the brand's acclaimed Matter-over-Thread universal compatibility with a retrofit design that preserves your original deadbolt hardware. The keypad adds Apple Home Key (NFC), fingerprint biometrics, and PIN code access without requiring any changes to your door's exterior appearance. For Apple-ecosystem users renting an upscale apartment or living in a condo with exterior hardware restrictions, the U200 is the pinnacle of what a retrofit lock can achieve. Reviewed.com named it the outright best smart lock of 2025.

Level Bolt is the most discreet retrofit lock available: it replaces only the internal deadbolt mechanism while leaving the exterior thumb turn, keyhole, and all visible hardware completely unchanged. There is zero indication from the outside that any smart lock is present — a security advantage and an HOA/landlord compliance asset simultaneously. Bluetooth-connected to the Level app, it enables tap-to-unlock, access sharing, and door activity logging. Apple Home integration allows Siri commands and automation. Reviewers in urban apartments and managed buildings consistently rate this as their only viable smart lock option.