August Smart Lock 3rd Gen: Bluetooth Deadbolt Retrofit

The August Smart Lock 3rd Gen is a Bluetooth retrofit deadbolt that installs on the interior thumb turn of your existing door hardware. Your exterior hardware, cylinder, and standard keys stay in place. The upgrade is entirely interior, which means the outside of your door looks unchanged and standard keys keep working. This is the Bluetooth-only generation, remote access requires the separate August Connect Wi-Fi bridge, which is not included.

How the Retrofit Installation Works

August's retrofit approach is the defining feature. Instead of replacing your entire deadbolt, the Smart Lock 3rd Gen mounts over the interior thumb turn using included adapters. The lock ships with adapters for the most common thumb turn sizes, and the August app walks through each step. Most installations take 10-15 minutes with a Phillips screwdriver and no special tools.

The 3rd Gen fits most standard US single-cylinder deadbolts. August's compatibility page lists confirmed fits by brand and model. Renters benefit most from this design, the lock removes cleanly and leaves no trace on the door, so it works in apartments where replacing hardware isn't allowed.

What's in the Box

• August Smart Lock 3rd Gen unit
• DoorSense magnetic sensor and mounting hardware
• Thumb turn adapters (multiple sizes)
• 4 AA batteries (pre-installed)
• Installation manual

DoorSense: Why Door Position Matters

DoorSense ships with the 3rd Gen and tracks whether the door is physically open or closed. This is independent of the deadbolt position. A door can be closed with the deadbolt retracted, or someone could leave the door cracked open while the bolt is thrown. DoorSense monitors actual door position and surfaces it in the August app.

Auto-lock uses DoorSense data directly. The lock won't engage the deadbolt unless DoorSense confirms the door is fully closed. This prevents the deadbolt from extending into an open doorway, a safety detail that matters on doors with frequent foot traffic.

Bluetooth Range and Remote Access

Out of the box, the 3rd Gen communicates over Bluetooth. The app connects automatically when your phone is within Bluetooth range, typically 30-50 feet. For remote access, locking or unlocking from outside that range, viewing the activity log while away, or using Alexa and Google Home, the August Connect Wi-Fi bridge is required.

The Connect bridge is a small plug-in device that pairs to your home's 2.4 GHz network and relays commands between the internet and the lock's Bluetooth radio. It sells separately for around $59. If you know you'll want remote access, factor that cost into the total.

Voice Assistant and Smart Home Integration

With the Connect bridge installed, the August Smart Lock 3rd Gen supports:

• Amazon Alexa: lock, unlock, and check status via voice
• Google Assistant: lock and check status via voice
• Apple HomeKit: full Home app integration, Siri commands, HomeKit automations
• August app: access log, guest key management, auto-lock scheduling

Without the bridge, none of these integrations work. The lock is Bluetooth-only at its core.

Auto-Lock and Auto-Unlock

Auto-lock engages the deadbolt after a configurable delay ranging from 30 seconds to 30 minutes. Combined with DoorSense, it only triggers when the door is fully closed. The delay is set in the August app and applies consistently.

Auto-unlock uses your phone's location. The August app detects when you cross a geofence boundary near home and prepares the lock. The actual unlock happens when the lock detects your phone via Bluetooth at close range. This two-step approach reduces false unlocks from driving past the house.

Guest Access and Activity Log

The August app supports up to 100 guest access configurations. Guest keys are time-limited, you set the valid days and hours, and they expire automatically. This works well for cleaners, dog walkers, or short-term guests. The activity log records every lock and unlock event with a timestamp and the identity of who triggered it, whether a keypad entry, app command, or auto-unlock.

3rd Gen vs Wi-Fi Smart Lock Pro

The 3rd Gen is the right choice if you're comfortable with the bridge trade-off and want a lower entry price at $99. The August Wi-Fi Smart Lock Pro at $149-229 includes built-in Wi-Fi and skips the bridge entirely. For most new buyers who need reliable remote access, the Pro is the cleaner solution. The 3rd Gen makes sense for Bluetooth-only use cases, households with the bridge already, or budget-focused upgrades.

Battery Life Improvement Over 2nd Gen

The 3rd Gen ships with 4 AA batteries and August rates it at up to 6 months of typical use. August redesigned the Bluetooth communication in the 3rd Gen to reduce battery drain compared to the 2nd Gen, which had a reputation for faster discharge. Lithium batteries extend life in cold-climate installations.

Low-battery notifications arrive in the August app and optionally through connected smart home platforms before the lock stops responding.

Final Assessment

The August Smart Lock 3rd Gen delivers the core retrofit value, no door modification, existing keys preserved, and smart lock features added to your current deadbolt. DoorSense, auto-lock, and guest key management work reliably. The Bluetooth-only limitation is a real constraint; remote access requires the $59 Connect bridge, pushing total cost to $158.

For households that already own the bridge or plan to use the lock in Bluetooth-only mode, the 3rd Gen at $99 is a solid, practical choice. For anyone starting fresh who needs remote access included, the August Wi-Fi Smart Lock Pro is worth the additional cost.