Yale's first smart locks for the UK and European markets were rather light and required the complete replacement of the existing lock.

With the Yale Linus smart door lock, things get a lot easier because this model is built to fit and work with an existing lock so it can be installed in minutes. This type of lock, which does not eliminate the features of an existing door, is our favorite type of smart lock.

In addition to being easier to install, Yale used the technology it acquired in August, as well as adding HomeKit support and a new bridge that gives you remote control.

Here is our full Yale Linus review ...

Yale Linus Smart Door Lock: Design and installation

Like the Nuki Smart Lock 2.0, the Yale Linus Smart Door Lock is built to work with an existing door. Instead of having to replace the door mechanism and the cylinder, Linus fixes itself on the door and turns an existing key.

Available in white or black, Linus is a pill-shaped lock that blends in with its environment.

The main benefit of this design is that the existing keys continue to work from the outside, giving you a manual way to enter your home.

In the case of previous Yale locks, such as the Conexis L1, there was no external keyhole, so there was no manual way to enter if the lock broke.

With Linus, the only requirements are that you have a lock that can work from the outside with a key inserted inside and that your cylinder is deep enough.

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If your lock doesn't touch them, Yale sells an adjustable Linus cylinder that you can mount on any door, though you may need a locksmith to do the job.

Finally, the last thing you need to check is clearance. As the Linus is a bit thick (147x 52 x 47mm), you will need to make sure that the lock will fit without touching the door frame.

Most doors that open internally will be fine, but doors that open to the outside can be a problem. The easiest thing to do before you buy is to use the Linus compatibility checker.

With a compatible door, installing Linus is easy. All you have to do is mount the mounting bracket, using the pad provided, glue a key to the door and then secure the lock to the bracket, pushing in the side wings to lock it all.

At this point, you can lock and unlock the door using the thumb rotation on the inside, which is a good safety feature, as it facilitates leaving the house in case of fire.

To connect the locking device to the application, you need to insert four AA batteries by pushing the flap on the front of the locking device.

Yale Linus Smart Door Lock: Features

The simplest, Yale Linus works via Bluetooth through the Yale Access application. This takes you through the initial pairing routine, and if you have an iPhone, you have the option to add and lock it to the HomeKit.

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At this point, the application leads you through the initial lock configuration. You are required to manually turn your thumb to lock and unlock the door so that Linus can learn exactly how far to turn. You are also asked what type of door you have and whether you need to lift the handle before locking.

You can also use optional DoorSense: a magnetic sticker that the lock uses to determine if the door is open or not. It works at a good distance: ours was installed 9 cm from the main lock, with the magnet glued to the front of the other smart lock, a Yale Conexis L1.

At this point, you can use the app to lock or unlock your door, and you can do the same with the Home app. The blockage is quite quick to respond and is very quiet, much quieter than the rival Nuki blockade, in fact.

From the app, you can see the status of your lock and whether the door is open or not.

From the app, there are some automatic rules that you can use to make your door work easier. Automatic unlock will detect when you enter an area and then automatically unlock Linus when you are a few meters away. This saves faffing by trying to find your key or unlock your phone.

Smartly, automatic unlocking only works when you've first left an area, so your door won't unlock just because you've been in the garden and returned home.

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If you have not told the system that you need to lock your door by lifting the handle, then you will also receive an Auto-Lock option, which locks the door when it is closed. It is neat and automatically uses the lock; but if you have a door where you have to lift the handle, you will have to lock the door manually, as the Auto-Lock option disappears. Doing this with the app is annoying, so the optional Linus Smart keyboard (GBP 59.99) may be worth buying because it gives you a dedicated lock button.

It would be good for Yale to simply change the Auto-Lock option so that Linus locks up about 30 seconds after the door closes, to give you time to lift the handle.

This keyboard also gives you PIN access to your home, which is great for giving visitors or workers access, or even for Airbnb integration. A keyfob, like Nuki's, would also be nice.

In a smart configuration for the Apple home, you can build HomeKit automations around your Linus, we say you turn off the SimpliSafe alarm when the door is unlocked.

Provided you have a HomeKit Hub configuration and within Linus' Bluetooth range (such as an Apple TV or HomePod) you can also gain remote access. This can save you the expense of purchasing Linus Connect Bridge, which gives you remote access through the app.

That being said, the Linus Connect Bridge is still a useful tool. A small connection box to be placed within the Bluetooth range of the locking device, Bridge is also the gateway to Google Assistant or Amazon Alexa support.

Using any of the voice services, you can lock and unlock the door with your voice, although the latter requires you to set up a voice PIN. Siri support is slightly different: you can lock yourself in with your voice, but you need to sign in with your phone to unlock it.

With Bridge you will also receive IFTTT assistance, offered through the August service. Using this, you can build your own smart rules: ours is set to turn off the Call Alarm (via the SimpleCommands service) when the Linus lock is unlocked.

Yale also has its own smart notification service, which is more useful with Bridge. Here you can create your own notifications, such as your ping if your door has been left open for a set period of time or if a specific user has unlocked the door.

Yale Linus Smart Door Lock: In use

Smart and efficient, the Yale Linus works without problems, and the automatic unlock function is an excellent saving. In fact, we rarely had to reach for our phone to return home. However, having a door that can be locked, the keyboard is really a necessity, otherwise it is too difficult to lock the door using the application.

It is very useful to have a key-locked external lock, as you can continue to use your old-fashioned door when needed. And it means you don't have to worry about the battery blocking.

This also emphasizes the importance of having the right type of cylinder. My original cylinder is a little too short, so you can't insert the keys on either side of the door at the same time. When you insert a key from the outside, a quick tap is enough to remove a little of the internal key, leaving the door to unlock from the outside.

However, this actually disables the smart lock and means it needs to be reset. Changing the adjustable cylinder fixes this.

How good the Linus Smart Door Lock is depends on the type of door you have. For ordinary locks on standard British or European doors, this model works efficiently and smoothly, leaving the original cylinder in place for key operation. If you have a lift-lock option, then you need to buy the keyboard to give you the dedicated lock button from the outside.

It's great to have the HomeKit in the box, plus the Google Assistant, Amazon Alexa and IFTTT option if you buy Bridge, making it one of the best connected smart devices available. The main competition for this type of lock is Nuki Smart Lock 2.0: Yale Linus is better made, looks more beautiful and is quieter in operation.

If you are looking for a simple upgrade to a stupid door, then this is currently the best thing you can get.