The Yale Assure Lock 2 is our pick for best smart lock for one structural reason: the radio is not part of the lock. It is a card in the back of the lock body, and Yale sells more than one. Everything else on this page follows from that.
The modular radio, and why it is the argument for this lock
Every other connected lock we rank makes you choose a protocol at checkout and live with it for the life of the hardware. Buy a Wi-Fi lock and you own a Wi-Fi lock until you replace it. Buy into a Bluetooth-plus-hub design and you own that hub arrangement forever.
Yale sells one Assure Lock 2 chassis and a small family of connectivity modules that slot into a bay behind the interior escutcheon. The lock body, the motor, the bolt, the keypad and the batteries stay exactly where they are; the radio comes out and a different one goes in. That converts a fifteen-year hardware decision into a reversible one.
The reason this matters is not theoretical. Home automation protocol fashion has turned over repeatedly - Zigbee, Z-Wave, Wi-Fi, and now Matter over Thread, which we cover in the Matter explainer. A deadbolt outlives at least two of those cycles. Being able to follow the standard without pulling hardware out of a door is worth more, over the life of the lock, than the one BHMA grade step that separates this from the Schlage.
The trade-off, stated plainly: the modules are a Yale product line, so you are betting on Yale continuing to make them. That is a smaller bet than betting a soldered radio will stay relevant, but it is a bet.
What keeps working with the internet down
Everything that happens at the door. The touchscreen keypad, the codes stored in the lock, the motor, the auto-lock timer and - on the keyed version - the mechanical cylinder are all local. They never routed through the radio to begin with.
What stops:
- Unlocking from somewhere that is not your doorstep
- Push notifications when the bolt moves
- Voice assistants and any cloud-side automation
- Adding or revoking a code from the app rather than at the keypad
That last one is the practical one. If the connection is down and you need to revoke a code, you do it standing at the door using the programming sequence in the manual, which is worth reading once before you need it.
This is the general shape for connected locks rather than something special about Yale, and the pattern is set out across brands in do smart locks need wifi. The reason it is worth stating on this page specifically is that with the Wi-Fi module fitted, this lock is often described as a Wi-Fi lock, and people reasonably assume a Wi-Fi lock stops being a lock when the Wi-Fi stops. It does not.
Keyed or key-free: the decision most people get wrong
Yale sells the Assure Lock 2 in both configurations, and this is the choice that will annoy you later if you rush it. The version we rank is the keyed one.
Keyed retains a mechanical cylinder below the touchscreen. That gives you a fallback that needs no power at all, and something physical to hand a contractor or an agent. It also keeps a pickable, bumpable cylinder in the door - the oldest attack in residential security, and the one a determined person is most likely to have a tool for.
Key-free deletes the cylinder entirely. There is no keyway to pick, no cylinder to bump, and nothing to be re-keyed by someone who should not be re-keying it. There is also no way in with flat batteries except the external terminal contact points, which need a 9V battery held against them.
The rule we would use: key-free if there is a second door into the house and someone in the household is reliable about low-battery warnings. Keyed if this is the only entrance, if anyone in the household regularly ignores notifications, or if you ever need to leave physical access with someone who will not install an app. Both configurations carry Yale's published BHMA Grade 2 for the Assure line.
Battery arithmetic: four AA cells, and what is actually drawing
The Assure Lock 2 runs on four AA alkaline cells in the interior escutcheon. Manufacturer battery-life figures in this category are published without a stated duty cycle - number of cycles per day, ambient temperature, radio configuration - so they are not comparable between brands and we do not quote them as if they were. What is comparable is the reservoir and the load.
The reservoir.Published cell datasheets put an AA alkaline at roughly 2,000 to 2,900 mAh at low drain. Four in series is about 6 volts, so the pack holds on the order of 15 watt-hours. For scale, the August retrofit's two CR123A cells hold on the order of 8 to 9, and the Level Lock+ runs a motor from a single CR2 at around 2.5. Four AA cells is a large reservoir by this category's standards.
The load, in two parts. The motor is a short, heavy pull - a second or so of current, a handful of times a day. The radio is a small, continuous pull, every second of every day, and in most connected locks it is the dominant term. That is the single most useful thing to understand about smart lock battery life: your lock is not being drained by being used, it is being drained by being reachable.
Which means the module you fit changes the arithmetic. A low-power module sleeps between events; a Wi-Fi module maintains an association with your access point around the clock. Same lock, same four cells, materially different intervals. It is one more argument for modularity: if battery changes start to irritate you, you can change the radio rather than the lock.
Two practical notes. Use alkaline unless Yale's documentation says otherwise - lithium AA cells have a different discharge curve and locks read voltage to estimate remaining life, so the warning can arrive late. And replace all four together, from the same pack; a mismatched set is the most common cause of a lock that reports low battery repeatedly and then works fine for another two months.
Fit and install: what to check before you order
This is a full deadbolt replacement, not a retrofit. You are taking the existing lock out and putting this in the same holes, which means three measurements have to agree:
- Backset - door edge to bore center, 2-3/8 in or 2-3/4 in on almost every North American door
- Cross-bore diameter - usually 2-1/8 in
- Door thickness - usually 1-3/8 in to 1-3/4 in
Check each against Yale's published ranges before ordering; our door fit guide shows where to put the tape measure, and how to install a smart lock covers the job itself. It is a screwdriver install on a door already bored for a deadbolt - no drilling, no wiring, typically well under an hour.
Two physical realities that the product photography understates. First, the interior escutcheon is large, because it houses the module bay, the motor and four AA cells. On a narrow door edge, beside a handle set, or in front of a storm door, measure the clearance. Second, the batteries live in the door rather than tucked out of sight, so the interior face of your door is going to look like a piece of hardware. If that is unacceptable, the in-bore Level Lock+ is the alternative, and it is ranked on our main locks page.
Before you fit anything, throw the existing bolt by hand with the door open and then closed. If closed is stiffer, the strike is out of alignment and the new lock's motor will fight it every cycle. Fix the strike, not the lock.
Who should skip it
Renters.This replaces the whole deadbolt, which means removing your landlord's hardware and putting it back at move-out. A retrofit that leaves the existing lock in place is the correct product, and those are ranked on best smart locks without drilling.
Anyone for whom the published grade is the deciding number. Yale publishes Grade 2 for the Assure line; Schlage publishes Grade 1 for its deadbolts. If that step is what you are buying, buy the Schlage Encode Plus - it is ranked second on our smart deadbolts page for build reasons and first for exactly this one.
Anyone who wants no radio at all. If the appeal of a keypad lock is that it has no account, no firmware and nothing to be reached from outside, a modular radio is solving a problem you do not have. Smart lock vs deadbolt walks that decision properly.
The thing this lock cannot tell you
Whether the door is shut. The Assure Lock 2, like every lock in this category, reports the position of the bolt. A bolt thrown into an open doorway reads as locked in the app.
A contact sensor on the frame closes that gap for a small fraction of what the lock costs, and it is the pairing we would recommend to anyone buying this - same buyer, same evening, same screwdriver. The ranked options are at best door and window sensors, and the wider family is at the sensors hub.
How this review was put together
Products we claim to have tested: zero. We have not put this lock on a door, and we are not going to imply otherwise. What this review is built from is Yale's published product and support documentation, the installation manual, the BHMA residential grading scheme, and published cell datasheets for the battery arithmetic above. Every one of those is a source you can open yourself, and they are listed below.
Our scoring rubric, and the weightings behind the metric scores on this page, are published in full at methodology. The point of publishing them is that you should be able to disagree with our conclusion using the same public material.
The alternatives worth comparing
Schlage Encode Plus - if the grade decides it
A published BHMA Grade 1, built-in Wi-Fi with no bridge, and Apple Home Key so an iPhone or Apple Watch tap opens the door - including on a phone that has dropped into power reserve. It is stronger hardware on paper than the Yale and costs accordingly. The catch is that a meaningful share of the premium over the standard Encode is Home Key, which is worth nothing at all in an Android household. No module bay: what you buy is what you own.
August Wi-Fi Smart Lock - if you cannot change the door
The opposite philosophy. It clamps over the existing thumbturn, leaves the exterior and your keys untouched, and reverses with a screwdriver, which makes it the answer for a rented door where the Yale is simply not an option. It runs on two CR123A lithium cells. The disqualifier is that there is no keypad in the box - guests need the app or a physical key - so if codes are the reason you are shopping, this is the wrong lock and the Yale is the right one.
Where the Yale sits between them
Schlage is the better single-purchase hardware. August is the only one of the three a renter can use. The Yale is the one that is still the right lock in six years, because the part most likely to become obsolete is the part you can replace. On a door you own, with a household that uses codes, that is the trade we would make - and it is why it heads our smart lock ranking and sits second on our deadbolt ranking, behind the Schlage on published grade alone. The rest of the category, including the retrofits and the radio-free keypad deadbolts, is indexed at the smart locks hub.
