Although many home automation makers were quick to embrace HomeKit when it first began to go mainstream, a lot of established companies are still releasing their first HomeKit products two to three years later. While there’s a tendency to dismiss some of these products as being too late to the game, some still offer unique functionality that make them worth considering, and such is the case with Yale’s Assure Lock SL, a touchscreen based deadbolt lock that replaces physical keys entirely and introduces HomeKit support through the addition of a new network module rather than an entirely new product.

While other smart locks we’ve looked at either attach onto your existing deadbolt and keyway or provide their own, Yale’s Assure Lock SL takes a different approach. Instead of combining a keypad and keyway like Schlage did with its Sense, Yale has chosen to eliminate the keyway entirely and just put the touchscreen right where you’d normally insert a physical key. In our opinion this makes for a much more elegant and classy design on the exterior of your door (Schlage’s Sense suddenly looks like a behemoth by comparison), but of course you’ll have to be willing to give up the security of being able to use a key as a backup. Having used smart locks on our home for the past two years, we’d say this is more a matter of perception than anything else, but it may be a point of concern for some, who may be legitimately concerned about malfunctions or dead batteries, although Yale offers a compromise for the latter case — contacts discretely located on the bottom of the keypad can be used to power the lock from a 9V battery in the event that the four AA batteries on the inside of the lock go dead.
The process of installing Assure Lock SL is about the same as for any other deadbolt. It’s a little more complicated than products like August’s Smart Lock Pro as you’ll need to replace the entire lock assembly, as opposed to only the interior thumb knob, but clear instructions are provided along with a full set of mounting hardware, including three lengths of bolts for various door thicknesses. It took us about 15 minutes to install it, and as long as you have a standard door it should be a cinch to install for anybody who is comfortable using a Phillips screwdriver. The front touchscreen portion of the lock entirely replaces your normal keyway, with a cable that routes through a backplate that screws onto the other side and the main component of the lock then attaching onto the backplate with three machine screws. Once you’ve installed the lock and inserted the batteries, voice prompts will guide you through the rest of the setup process, beginning with setting a master PIN code.
Another unique feature of Yale’s lock is that connectivity is provided via removable modules, rather than built into the lock itself. Without a module inserted, Assure Lock SL simply functions as a basic electronic lock, allowing you to set up to 25 PIN codes and configure other features like automatic lockout and vacation mode directly from the front keypad. Above the battery compartment, however, is a slot to insert a network module, and Yale sells various modules that provide support for different home automation protocols; the version we received of course included the iM1 Network Module for HomeKit support, but Z-Wave Plus, and Zigbee modules are also available separately. More significantly, however, this also means that if you already purchased an Assure Lock SL, you can simply purchase the iM1 module for $50 to add HomeKit support to your existing lock. We have to commend Yale for taking this approach, since it not only allows existing customers to easily gain HomeKit support, but also avoids platform lock-in and gives users an assurance that they can easily upgrade their lock should a hardware protocol change be required in the future.
The iM1 Network Module is packaged separately within the box, and contains the HomeKit pairing code both on the module itself and in the accompanying instructions, although only the latter one is designed to be scannable with your iPhone camera. Yale provides its own Yale Secure app which is designed specifically for the iM1 Network Module and HomeKit (not to be confused with the “Yale Assure” app, which is for the Bluetooth-only version of the lock). As with most HomeKit accessories, you don’t actually need to use Yale’s app to pair the Assure Lock SL with your HomeKit system — you can just it up right in Apple’s Home app — but the Yale Secure app is worth downloading as it provides the ability to set additional entry codes and configure lock settings directly from your iPhone rather than having to fiddle with punching in codes on the front keypad. In either case, the pairing procedure is initiated by typing in your master PIN code and pressing the asterisk key to enter configuration mode, and then pressing 7* to initiate network pairing.
As a HomeKit device, Assure Lock SL works in the same way as any other HomeKit lock.
You can tap on it from within the Home app to lock or unlock it, tell Siri to lock it, unlock it, or simply check if it’s locked, and add it to scenes, so for example you can automatically ensure all of your doors are locked at night when calling up your “Good night” scene. The Yale Secure app allows you to set up to 25 PIN codes (in addition to the master PIN), although unfortunately we were disappointed to discover that there is presently no way to create expiring codes or codes that are restricted based on time of day. A settings section within the Yale Secure app allows you to configure the lock’s settings; it’s worth noting that everything shown here can also be configured through the voice-prompted menus accessible from the front keypad, but obviously it’s easier to do on your iPhone.
We found that using the Assure Lock SL directly was a little bit more complicated than we expected. Most significantly, you can’t activate the touchscreen with only a single finger — you’ll need to tap it with the palm of your hand to light it up, or use at least three fingers. We found this a bit confusing at first — to the point of wondering if the lock was malfunctioning — and while it wasn’t too bad once we got used to it, we still found it unintuitive and a bit cumbersome. Although we appreciate that this prevents the lock from being activated too easily — which is especially important if one-touch locking is enabled — we still think there should be a better way to do this. Once the keypad is lit up, entering a code is simple enough, and Assure Lock SL provides the flexibility for any code to be between four and eight digits long, so you’ll need to press the checkmark key when you’re finished entering your code. A “One Touch Lock” setting can be enabled to automatically lock up just be tapping the keypad (again, with your whole hand), otherwise you’ll need to enter your PIN code to lock the door as well as unlocking it (or use HomeKit, of course). We were also disappointed to discover that Assure Lock SL doesn’t support proximity unlocking; although we consider this more of a bonus than a standard feature, it’s definitely something we’ve found very useful on August’s and Friday’s locks.
One unique feature that Assure Lock SL does offer, however, is “Privacy Mode.” Enabled by holding a small button on the inside of the lock, this disables all PIN codes — including the master code — when it’s engaged.