August Wi-Fi Smart Lock (4th Generation) Review: No Hub

If you want a smart lock but don't want to replace your deadbolt or buy a separate hub, this August Wi-Fi Smart Lock (4th Generation) review is for you. It sits over the inside of an existing single-cylinder deadbolt and turns it into a lock you can control from your phone. Wi-Fi is built in, so there is no bridge to plug in. It suits homeowners and renters who want a straightforward retrofit with wide voice assistant support, and it sits in the mid-range part of the market.

How the August Wi-Fi Smart Lock works

Most smart locks ask you to swap out the whole lock. August takes a different route. This model fits over your existing single-cylinder deadbolt, so the exterior of the door stays as it is and your original keys keep working. That matters in a few situations:

• You rent and don't want to alter the outside of the door.
• Other people in the household would rather keep using a key.
• You want a fallback if your phone dies or your Wi-Fi drops out.

The lock connects over Wi-Fi (802.11 b/g/n, on 2.4GHz or 5GHz) and also has Bluetooth Low Energy. Because the Wi-Fi is built in, the spec sheet lists no hub or bridge as required. Because Wi-Fi is built in, no hub or bridge is required.

August Wi-Fi Smart Lock (4th Generation) review: design and installation

August gives the lock's dimensions as a diameter of 72mm and a depth of 46mm. It comes in Silver or Matte Black, so you can pick a finish that suits your door hardware. The box includes the lock, a DoorSense sensor, two CR123 batteries, a lock adapter and mounting hardware, so you shouldn't need to buy anything extra to get started.

The headline for installation is speed. August says it installs in about 10 minutes, and the lock mounts over your existing deadbolt rather than replacing it.

The trade-off is size. A common criticism is that the unit is still fairly bulky on the inside of the door. If you like very low-profile hardware, look at photos or dimensions before you commit. For many people the bulk is a fair price for keeping the exterior untouched.

August's list of compatible deadbolts is "most single-cylinder deadbolts". Check that your door has a single-cylinder deadbolt before buying.

Features and what they mean day to day

Auto-lock and auto-unlock

The lock can unlock when you arrive and lock when the door closes. Reviewers say these automations work well, which matters because they are the main reason to own a smart lock. A door that locks itself removes the "did I lock it?" worry. Auto-unlock is handy when your hands are full.

DoorSense

The included DoorSense sensor reports whether the door is open or closed. It also makes the lock more useful as a status check. You can see whether the door was left ajar rather than just whether the bolt is thrown.

Virtual keys and the activity feed

You can send temporary, scheduled or recurring virtual keys to guests from the app. That covers a range of everyday situations without handing out physical keys:

• a one-off visit from a friend or tradesperson
• a regular visitor on set days
• a guest who only needs access for a limited period

The activity feed shows who comes and goes, which gives you a record of entries. It's a useful feature for families or anyone sharing access with several people.

Voice assistants and smart home platforms

The lock works with Alexa, Google Assistant, Apple HomeKit and SmartThings. This breadth is one of the lock's strengths, since few households use exactly one ecosystem and this covers the main ones.

The gap is Matter and Thread, which this lock does not support. If you're building a home around those newer standards, that is a real limitation. If you already use one of the four supported platforms, it may not matter to you.

Security

August lists two-factor authentication, plus AES 128 bit and TLS encryption. For a lock that is reachable over Wi-Fi, that's the kind of security detail you want to see published. The spec sheet gives no more detail than this, so I won't speculate beyond it.

Battery, power and connectivity

The lock runs on 2 CR123 batteries, which are included. August's own estimate for battery life is 3 to 6 months. The 3 to 6 month estimate is a drawback of this lock. In practice you should plan for a battery change a couple of times a year, and keep spare cells somewhere handy.

Because your original key still works, a flat battery is not the same as being locked out. That fallback is a real benefit of the retrofit design.

Keypad: optional, and sold separately

The keypad is optional and sold separately. Without it, your ways in are your phone, your voice assistant setups and your physical key. Without the keypad, entry without a phone or key is limited. That affects some households more than others:

• Children or older relatives who don't carry a phone may need a key or a keypad.
• Guests can use virtual keys, but that depends on them using the app.
• If you want code entry from day one, factor the extra accessory into your plans.

What experts like and what they criticise

Expert opinion is positive. The lock averages 8.9/10 across 3 expert reviews. Android Central gives it 4.5 out of 5, Android Police scores it 8/10 and TechGearLab gives it 4.8 out of 5.

Reviewers consistently praise:

• built-in Wi-Fi with no separate hub or bridge
• an installation of about 10 minutes over the existing deadbolt
• original keys that keep working
• auto-lock and auto-unlock that work well
• support for Alexa, Google Assistant, Apple HomeKit and SmartThings

A common criticism is:

• CR123 batteries rated for only 3 to 6 months
• a keypad that costs extra
• a unit that is still fairly bulky on the inside of the door
• no Matter or Thread support

Who should buy it

This lock makes sense if you:

• have a single-cylinder deadbolt and want to keep it
• rent, or otherwise don't want to change the outside of your door
• want a smart lock without buying or placing a hub
• use Alexa, Google Assistant, Apple HomeKit or SmartThings
• like the idea of sending guests temporary or recurring access

Who should skip it

Look elsewhere if you:

• have a double-cylinder deadbolt or a door that isn't a match for the supported hardware
• want a keypad built in rather than as an extra purchase
• dislike changing batteries more than a couple of times a year
• want Matter or Thread support
• prefer a slim, low-profile look on the inside of the door

How it fits in the smart lock category

Smart locks generally fall into two camps: full replacement locks and retrofit units that go over your existing hardware. This is firmly a retrofit unit. The advantages are quick installation and keeping your keys. The cost is that you carry the bulk of the unit on the inside of the door. Built-in Wi-Fi and the broad platform support make it flexible, though it does not support Matter or Thread.

If you're upgrading the front door more broadly, our Google Nest Doorbell review covers a video doorbell that could sit alongside a lock like this.

Verdict

The August Wi-Fi Smart Lock (4th Generation) does what a retrofit lock should. It adds app control, auto-lock, guest access and voice assistant support to the deadbolt you already have, and it needs no hub. Experts score it well, and the praise centres on the things that matter most: easy installation, working automations and wide ecosystem support. Go in with open eyes about the batteries, the optional keypad and the missing Matter support. If those trade-offs fit your home, it is an easy lock to recommend for a quick, low-effort smart upgrade.

Related buying guides

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