The August Smart Lock Pro earned its reputation by solving the problem most smart locks create: it upgrades your door without changing anything a neighbor or delivery driver can see. Because the August Smart Lock Pro mounts over the inside of your existing deadbolt, your keys keep working, your exterior hardware stays put, and installation takes about 10 to 15 minutes with a single screwdriver. That retrofit design is the core reason it remains a favorite among renters and homeowners alike.
This guide covers what the lock does, how it installs, its battery and connectivity, and how it stacks up against August’s newer Wi-Fi Smart Lock so you can decide if it fits your door.
The Retrofit Design Advantage
Unlike locks that replace the entire deadbolt and cylinder, the Pro attaches only to the interior thumb-turn. You keep your current keyed cylinder on the outside, so anyone with a physical key still gets in, and the door looks completely ordinary from the street. That matters for two groups: renters who cannot alter the exterior door, and homeowners who want to keep matching hardware.
The lock is a squat cylinder roughly 2.8 inches in diameter and 2.2 inches deep. It works with most standard single-cylinder deadbolts from brands like Kwikset, Schlage, and Baldwin, though August’s compatibility checker is worth using before you buy.
Key Features Worth Knowing
The Pro model packs the features that lower-tier August locks leave out. Here is what you actually get:
- Auto-Lock and Auto-Unlock: The lock senses your phone approaching and unlocks as you walk up, then relocks automatically after you enter.
- DoorSense: A magnetic sensor tells you whether the door is actually closed, not just locked, so you never leave it ajar and bolted into open air.
- Z-Wave Plus: Built-in Z-Wave lets the Pro tie into hubs like SmartThings, Ring Alarm, and other home-security systems.
- Apple HomeKit, Alexa, and Google Assistant: Voice control and remote access work across all three major ecosystems.
- Guest Access: The app issues time-limited digital keys for guests, cleaners, or dog walkers without handing out a physical key.
The included Connect Wi-Fi Bridge is what unlocks remote features. Plug it into an outlet near the door, and you can lock, unlock, and check status from anywhere, plus enable voice assistants.
Installation: About 15 Minutes
Few smart locks are as forgiving to install. You do not touch the exterior hardware at all.
- Remove the two screws holding the interior thumb-turn plate and take off the thumb-turn.
- Attach the August mounting plate to the existing deadbolt hardware.
- Choose the correct adapter for your deadbolt tailpiece from the several included.
- Clip the August lock body onto the mounting plate and twist to secure.
- Install the four AA batteries and calibrate the lock in the August app.
The app walks you through calibration, where the lock learns the locked and unlocked positions. Budget 10 to 15 minutes total. No drilling, no wiring, and nothing that would jeopardize a security deposit.
A few install tips save headaches. Make sure your deadbolt already throws smoothly by hand before you mount the August; a stiff or misaligned bolt will cause jams the motor cannot overcome, and you will get “unable to lock” errors in the app. If the door binds, adjust the strike plate first. Mount the Connect bridge within about 15 feet of the lock and on the same floor, since thick walls degrade the Bluetooth link between them.
Battery Life and Power
The Pro runs on four AA batteries seated in the back of the unit. Real-world life lands around three to four months for average households, less if you use auto-unlock heavily, since the Bluetooth ranging drains cells faster. The app sends a low-battery alert well before you get locked out, and swapping fresh AAs takes under a minute by popping the faceplate.
Keep a spare four-pack in a nearby drawer and you will never be caught out. In a pinch, if the batteries die completely, your original physical key still opens the door from outside, a reassurance that all-electronic locks cannot offer.
Use standard alkaline AAs rather than rechargeables. The lower voltage of rechargeable NiMH cells can trip a false low-battery warning and cut life short. Lithium AAs last longer in cold climates if your entry door sees freezing temperatures on the interior thumb-turn side.
Everyday Use and the App
Day to day, the August app is where you live with the lock. It logs every entry and exit with a timestamp and name, so you can see when the kids got home from school or confirm a house cleaner arrived on schedule. Auto-Unlock uses your phone’s location plus Bluetooth to detect a genuine arrival, so it will not pop the door just because you walked past a window inside the house.
Guest keys are the standout feature for busy households. You can grant a dog walker access weekdays from 11 a.m. to 1 p.m., or hand a weekend guest a key that expires Sunday night, all without cutting a physical copy. If you list a spare room on a short-term rental platform, this scheduling alone can justify the lock. One caveat worth planning around: because there is no built-in keypad, every guest needs a smartphone and the free August app to use their digital key.
Price and What’s in the Box
The Pro typically sells for $229 to $279, often bundled with the Connect Wi-Fi Bridge. Watch for holiday and Prime Day sales that regularly drop it closer to $200, which makes the bundle a genuine value. The box includes the lock body, mounting plate, multiple deadbolt adapters, the DoorSense sensor, four AA batteries, and the Wi-Fi bridge in the Pro bundle.
Compared with a full-replacement smart deadbolt at $150 to $300, the Pro sits in the mid-to-upper range, but you are paying for the retrofit convenience and the broader connectivity, including Z-Wave, that cheaper locks skip.
Pros and Cons
No lock is perfect. Weigh these before you buy:
- Pros: Keeps your existing key and exterior hardware, fast tool-light install, DoorSense status, works with HomeKit, Alexa, Google, and Z-Wave, reliable auto-unlock.
- Cons: Bulky interior profile, battery drain with heavy auto-unlock use, requires the separate bridge for remote access, no built-in keypad, so guests need the app.
Pro vs. the Newer Wi-Fi Smart Lock
August’s Wi-Fi Smart Lock, released after the Pro, is about 45 percent smaller and folds the Wi-Fi radio inside the lock, so you skip the separate bridge. It is the better pick for most buyers who want a slimmer unit and built-in Wi-Fi at a similar price. The Pro still wins on one point: it includes Z-Wave, which the Wi-Fi model drops. If you run a Z-Wave-based security system like SmartThings or Ring Alarm and want the lock on that network, the August Smart Lock Pro remains the model to buy. Otherwise, the newer Wi-Fi version is the more streamlined choice.
Is It the Right Lock for You?
Buy the Pro if you want to keep your keyed entry, care about door-status sensing through DoorSense, and either own a Z-Wave hub or simply prefer the broadest compatibility on the market. It shines for renters, for households that share access with cleaners and dog walkers, and for anyone nervous about giving up a physical key entirely.
Skip it if you specifically want a keypad for keyless entry, since the Pro relies on the app; August’s Smart Lock with a Wi-Fi keypad add-on or a competitor like the Schlage Encode suits that need better. But for its core mission, retrofitting a standard deadbolt into a connected, app-controlled lock in a quarter of an hour, the August Smart Lock Pro is still one of the most sensible smart locks you can install, and the fallback of a working brass key keeps it practical for the long haul.
