August Smart Lock 4th Gen Review

The August Smart Lock 4th Gen has quietly become one of the most talked-about smart locks for homeowners who want keyless convenience without ripping out their existing deadbolt. It installs on the interior side of your door, leaving your existing keyed cylinder in place — meaning you keep your keys, your locksmith, and your landlord's approval. That's the core pitch, and for a lot of buyers, it's enough.

Installation: Genuinely Easy, With One Caveat

Most users get this thing installed in under 15 minutes. The mounting system uses an adapter plate that fits the vast majority of standard deadbolts, and the magnetic cable connection for the battery pack is satisfyingly simple. No wiring, no drilling, no handyman required.

The caveat? A small number of older or non-standard deadbolt configurations don't play nicely with the adapter system. Before you buy, it's worth measuring your existing thumb-turn to make sure it'll mate with August's hardware. This isn't a dealbreaker for most, but it's the kind of thing that sends a frustrated minority back to the returns counter.

Auto-Unlock: The Feature Everyone Wants, Few Set Up Correctly

Here's one of the most valuable pieces of information for prospective buyers, surfaced from real testing: the Auto-Unlock feature is frequently inconsistent — and it's almost never the hardware's fault.

The Auto-Unlock relies on your phone's geofencing to detect when you're returning home. The problem is that phone operating systems (especially iOS) aggressively throttle background location access to save battery. If your phone's location permissions aren't set to "Always" (not just "While Using"), the lock simply won't know you've arrived. Additionally, if your home Wi-Fi connects too quickly as you approach, your phone can sometimes register as "already home" before you've left — which means the geofence departure event never fires, and Auto-Unlock never arms itself for your return.

The fix: make sure Location Services is set to Always for the August app, disable any battery optimization settings that affect it, and give the feature a few days to learn your patterns before judging it. Once properly configured, it works reliably.

App and Smart Home Integration

The August app is polished and functional. You can grant access to guests with time-limited virtual keys, check lock/unlock history, and receive activity notifications. Auto-lock (locking after a set period) works consistently and is genuinely useful if you have kids or a habit of second-guessing yourself halfway to work.

For smart home users, the 4th Gen works with Alexa and Google Assistant natively. Apple HomeKit support is available but requires the August Wi-Fi Bridge (sold separately in some configurations, bundled in others — check your package). If you're deep in a HomeKit or Home Assistant setup, verify compatibility before purchasing.

Battery Life: Realistic Expectations

August rates the 4th Gen for roughly 3-6 months of battery life on four AA batteries. Real-world usage lands closer to 3 months for households with frequent entries and active auto-lock. Heavier users — families with kids coming and going — should plan for quarterly battery swaps. The app sends low-battery warnings with enough lead time that you won't get locked out, but it's worth keeping a set of AAs in a kitchen drawer.

Who This Is Actually For

This lock makes the most sense for renters (who can't replace hardware permanently), homeowners who want a minimal-footprint upgrade, and anyone who frequently lets in guests, dog walkers, or cleaning services. The virtual key system is genuinely convenient for that last group.

It's less ideal if you want a keypad for entry without a phone — there's no built-in keypad on the standard 4th Gen unit. You'd need August's Keypad accessory (sold separately) for that. If a keypad is non-negotiable, brands like Schlage or Wyze offer deadbolt replacements with built-in keypads at similar price points, though you lose the "keep your existing cylinder" advantage.

Build Quality and Longevity

The lock feels solid and well-built. The motor mechanism is quiet — noticeably quieter than earlier August generations — which matters if you're coming home late and don't want to wake anyone. There are no widespread durability complaints in the 6-12 month range that would constitute a red flag, which is encouraging for a mechanical device that cycles multiple times daily.

Buyer Tips

• Set Location Services to "Always" before you even finish installation — don't wait until Auto-Unlock fails.
• Enable Door Sense (the included door position sensor) — it prevents the lock from auto-locking when your door is open, which saves motor wear and the embarrassing moment of your door slamming into a locked deadbolt.
• If you plan to use it with HomeKit, confirm whether your purchased version includes the Wi-Fi Bridge or requires a separate purchase.
• Update the firmware immediately after setup — early firmware versions had connectivity quirks that patches have since resolved.

Frequently Asked Questions

Q: Does the August Smart Lock 4th Gen work with Apple HomeKit?

A: Yes, but HomeKit support typically requires the August Connect Wi-Fi Bridge. Some bundles include it; others don't. Check what's in the box before assuming full HomeKit functionality out of the box.

Q: Does it have a keypad, or do you need your phone every time?

A: The standard 4th Gen does not have a built-in keypad. You can add August's separate Smart Keypad accessory, or use your original physical key — which still works since the lock doesn't replace your cylinder.

Q: How long do the batteries last in the August 4th Gen?

A: Officially 3-6 months on four AA batteries. Realistically, expect closer to 3 months with frequent use and active auto-lock. The app gives advance warning before the battery dies.

Q: Will it fit my existing deadbolt?

A: It's compatible with the vast majority of standard single-cylinder deadbolts. August includes multiple adapter plates. That said, non-standard or oversized thumb-turns on some older locks may not be compatible — measure your thumb-turn before purchasing.

Q: Is the Auto-Unlock feature reliable?

A: Yes, once correctly configured. The most common issues stem from phone location permissions not being set to "Always" or battery optimization settings interfering with background location. Fix those settings first before concluding the feature doesn't work.

At its price point, the August Smart Lock 4th Gen delivers a genuinely smart, renter-friendly upgrade to your front door. The learning curve is real but short, and once dialed in, the convenience — especially if you're managing access for multiple people — is hard to give up.

— Home Lead Editor, CPrice