Do Smart Locks Lock Automatically?

Most smart locks can lock themselves, and almost none of them do it until you ask.Auto-lock is a feature you switch on in the app, choose a delay for, and then forget about — which is exactly the point, because the thing it protects you from is forgetting.

Yale publishes Auto-Lock with DoorSense on the Assure Lock 2. Schlage publishes auto-lock with a choice of time delayson the Encode Plus. Both are properties of the lock, not of a subscription — nothing in this guide costs anything monthly, as we set out in do smart locks require a subscription?

But the interesting part of this question is not whether the feature exists. It is that there are two completely different kinds of auto-lock, they feel the same in the app, and only one of them is a good idea on a door you use every day.

Auto-lock on a timer, and why it goes wrong

The simple implementation is a countdown. The lock notices it has been unlocked, waits the number of seconds you chose, and throws the bolt. That is all it knows: its own bolt position.

Which means it does not know whether the door is shut. If you have propped it open to carry shopping in, the timer still runs out, and the bolt extends into the open air where the strike plate should be. Now the door physically cannot close, and the usual next event is somebody pushing it hard enough to scrape the bolt across the frame. Do that for a year and you have damaged both.

That failure mode is why so many people enable auto-lock, get annoyed in the first week, and switch it off again — which leaves them with none of the benefit. The feature is not the problem; the missing information is.

Auto-lock that knows the door is closed

The better implementation adds one cheap part: a sensor that reports whether the door is open or closed. Yale calls it DoorSense, and publishes Auto-Lock with DoorSense as a single feature on the Assure Lock 2 — the two things belong together.

With that sensor fitted, the logic changes completely. The lock waits for the door to actually close, then starts its delay, then locks. Prop the door open and nothing happens. Carry four bags in over two minutes and nothing happens. Pull it shut behind you and thirty seconds later your house is locked, without you thinking about it.

You can see how seriously Yale treats the distinction in a different place entirely: in Yale’s own Google Home documentation, “Hey Google, is my front door locked?” works on any Assure lock, while “Hey Google, is my front door closed?” requires DoorSense. Locked and closed are genuinely different facts, and only one of your locks knows both.

If your lock has no door sensor, you are not stuck — you are just relying on the door itself. A door with a properly adjusted latch that pulls shut and catches every time is safe to put on a timer. A door that needs a shoulder, sticks in summer, or sits in a frame that has moved is not, and the right fix is a carpenter rather than a longer delay.

What each lock we cover publishes

The second row is the one to read. Two of the four locks publish a door-position sensor, and those are the two we would put auto-lock on without hesitating.

Auto-lock is not auto-unlock, and the difference matters

These get conflated constantly and they pull in opposite directions. Auto-lock makes your house more secure by removing a human failure. Auto-unlock makes it less secure in exchange for convenience: the lock sees your phone approaching and opens the door before you touch it. The listing for the August Wi-Fi Smart Lock bundle lists auto-unlock and DoorSense among what is included, and it is genuinely lovely when your hands are full.

It is also the feature to think hardest about. Geofencing is not precise, and a phone in your pocket while you are in the back garden or on the pavement outside can be close enough to count as having arrived. If you enable auto-unlock, enable auto-lock alongside it, so that a door opened by a false positive does not stay open all afternoon.

There is one more connection worth knowing: on the Home Assistant side, auto-unlock is what creates the offline keythat local Bluetooth control depends on — the key only exists if auto-unlock has been enabled and used at least once. So on a local-first setup, auto-unlock stops being purely a convenience and becomes part of the plumbing. That is covered in best smart locks for Home Assistant.

How to set it up so you do not turn it off again

Fix the door first. If the latch does not catch on its own every time, nothing downstream will work properly. This is five minutes with a screwdriver on the strike plate, most of the time.

Fit the door sensor if your lock has one. On the Yale and the August it comes with the lock and people skip it because it is an extra adhesive part. It is the component that makes the whole feature behave.

Start with a long delay. Two or three minutes for the first week. Watch how your household actually uses the door, then shorten it. A delay that is too short is the fastest route to switching the feature off.

Put a backup outside the house before you enable it. A lock that closes behind you is a lock that can close behind you while the keys are on the kitchen table. Yale and Schlage both include a physical key; where it lives is the decision. The routes each lock publishes are laid out in do smart locks work without power? and can you still use a key with a smart lock?

If the door is a rental changeover, auto-lock is not optional.A guest who leaves the door open is a problem you cannot see from another city. Yale and August both publish Airbnb integrations that expire a code at checkout, and auto-lock is what makes the expiry meaningful — the picks are in best smart locks for Airbnb and rentals.

Three locks that do this properly

Two with a published door sensor, and one for the household that wants the strongest hardware and will accept a timer.