August Wi-Fi Smart Lock (4th Gen): Easy Retrofit Keyless Entry, but Is the Battery Life Worth It?

The August Wi-Fi Smart Lock (4th Gen) installs on the inside of your door and works seamlessly with your existing deadbolt and keys—no exterior hardware changes required. Source: Official August Home / Amazon product listing

Introduction

Smart locks used to feel like a luxury. Now, they’re one of the most practical upgrades you can make to a front door. You get keyless entry, remote locking, guest access, and peace of mind—without having to hide spare keys under a mat. **The August Home Wi-Fi Smart Lock (4th Generation)* takes that idea and focuses on one simple promise: make your existing deadbolt smarter in minutes, without changing how your door looks from the outside.*

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That “retrofit” approach is what made August famous. The 4th-gen model (AUG-SL05-M01-G01) shrinks the hardware, builds Wi-Fi into the lock itself, and leans hard into automation like Auto-Unlock and DoorSense Auto-Lock. However, real owners highlight a trade-off: convenience comes fast, but batteries can go faster. Across Amazon, Home Depot, Best Buy, and long-running user threads, people consistently praise the easy installation and reliable Bluetooth control—while also complaining about Wi-Fi connectivity quirks and short battery life when Wi-Fi is enabled.

So, is this still one of the best retrofit smart locks you can buy in 2025? Let’s break it down in plain English.

What Is It?

The August Wi-Fi Smart Lock (4th Gen) is a keyless entry smart lock that mounts on the inside of your door, over your existing single-cylinder deadbolt thumbturn. Nothing changes on the outside, which means your current key still works and your door keeps its curb appeal.

This specific SKU comes in matte black, with a compact round body that’s about 45% smaller than older August models.

Who Makes It?

August Home is a San Francisco-based smart-home company founded in 2012. It pioneered the mainstream retrofit smart lock category and is now part of the larger Yale/August ecosystem, under a global lock-hardware parent company.

In practice, that means August locks often share accessories and app platforms with newer Yale products while still keeping their signature retrofit design.

How Does It Work?

August installs on the inside of your door. You remove your deadbolt’s interior thumbturn, attach an adapter, and then mount the August lock over it. Your exterior cylinder stays untouched, so you can still use keys as a backup.

Once installed, the lock communicates in two ways:

1. Bluetooth (low power, close range): Your phone talks directly to the lock when you’re nearby.
2. Built-in Wi-Fi (remote control): The lock connects to your home network so you can lock/unlock from anywhere—no separate bridge required.

It runs on two CR123A batteries, with August estimating about three months of life under typical Wi-Fi use. Real-world results vary a lot, which we’ll cover later.

Key Features and Their Benefits

1. Built-In Wi-Fi (No Hub Needed)

Older August locks needed the separate August Connect bridge for remote access. The 4th-gen model has Wi-Fi inside the lock, so remote control works out of the box. Benefit: One less piece of gear, simpler setup, and fewer outlets taken up.

2. Retrofit Design That Keeps Your Exterior Hardware

Because the lock only replaces the interior portion of your deadbolt, you keep your keys and your outside look. Renters and homeowners love this.

Benefit: No landlord drama, no rekeying, and no bulky keypad on the outside unless you add one.

3. DoorSense + Auto-Lock

The included DoorSense sensor helps the lock know when your door is closed. Pair that with Auto-Lock, and the lock can secure itself a few seconds after you shut the door.

Benefit: Great for families, kids coming and going, and anyone who forgets to lock up.

4. Auto-Unlock (Hands-Free Entry)

With Auto-Unlock enabled, the lock uses Bluetooth and geofencing to unlock when you arrive home.

Benefit: No fumbling with keys when your hands are full.

Reality check: Some owners say Auto-Unlock can be iffy depending on phone settings and location accuracy, especially on multi-door setups.

5. Virtual Guest Keys and Activity Log

You can invite guests through the August app, set schedules, and see who locked/unlocked and when.

Benefit: Perfect for dog walkers, cleaners, Airbnb hosts, or family visits—without making physical copies.

6. Works With Major Smart-Home Platforms

August supports Alexa, Google Assistant, and Apple HomeKit/Siri.

Benefit: Voice control, automations, and integration with routines (like “Goodnight” locking all doors).

Pros and Cons

Pros:

Easy retrofit install. Most users report a 10–20 minute setup with basic tools. No exterior changes. Keeps your original key and outside hardware.

Built-in Wi-Fi remote access. No bridge required for standard remote control.

Excellent app experience. Activity logs, guest scheduling, and DoorSense automation are consistently praised.

Great for renters and shared homes. Easy to remove and take with you later.

Cons:

Short battery life on Wi-Fi. Many owners see 1–3 months, and some report faster drain, especially with mesh networks.

Wi-Fi connectivity can be inconsistent. Bluetooth is usually solid, but Wi-Fi dropouts show up in forums and reviews.

Auto-unlock reliability varies. Some users love it; others call it hit-or-miss depending on the phone and location.

Real User Testimonials (Good + Bad Common Themes)

Here’s what real owners consistently say across major retailers and user communities:

What people love

“Installation was painless.” Many buyers say they were surprised by how quickly it attached to their existing deadbolt and that calibration was simple.

“Perfect for renters.” Users like keeping their original keys and not changing the door’s outside appearance.

“The app is the best part.” People routinely praise guest access, temporary keys, and the activity feed as reliable and easy to use.

“Bluetooth works great.” When connecting locally, owners say locking/unlocking is quick and dependable.

What people complain about

Battery drain with Wi-Fi. This is the biggest recurring negative. Some users say the batteries die in weeks or even days, while others hit the 2–3 month mark and still feel it’s too short.

Mesh Wi-Fi issues. Multiple threads mention faster battery drain or unstable Wi-Fi when the lock is on certain mesh systems, leading some owners to disable Wi-Fi and rely on Bluetooth hubs instead.

Auto-unlock inconsistency. Some users report delays or missed unlocks, and others dislike that troubleshooting is finicky (location services, battery level, background app refresh).

Battery reporting feels “weird.” Owners note that the lock sometimes shows low battery early or doesn’t warn in time.

Support and reliability frustrations. A smaller but loud group feels build quality and support responsiveness have dipped compared to older August generations.

The overall vibe

Most buyers still like the lock, especially for convenience and retrofit simplicity, but many wish it had better battery life and more consistent Wi-Fi. That trade-off is basically the whole story of the 4th-gen August.

Final Verdict

The **August Home Wi-Fi Smart Lock (4th Generation)** is still one of the easiest ways to upgrade a deadbolt. Installation is simple, the retrofit design is renter-friendly, and the app experience is polished. DoorSense and Auto-Lock add real everyday value, and Bluetooth control is reliably strong.

Nevertheless, the lock’s biggest downside is also its most common real-world complaint: battery life on Wi-Fi is short and inconsistent. In many homes it lasts the promised ~3 months, but in others—especially with mesh Wi-Fi—it can drain far quicker. Thankfully, users who switch to Bluetooth-only often see huge battery improvements, but that adds a layer of setup you may not want.

Bottom line: If you’re after a clean retrofit smart lock with a great app and you’re okay swapping CR123A batteries a few times a year, this is a smart buy. If battery life is your #1 concern, newer retrofit competitors may fit your life better.

If the **August Wi-Fi Smart Lock** matches your needs—especially if you want fast retrofit installation and key-backup convenience—it’s a solid upgrade. Check current pricing and bundles on our site, and if the features line up with your home setup, this lock can genuinely make day-to-day life easier and more secure.

This article was written with AI assistance and researched and edited by the author for clarity and accuracy.