Nuki Smart Lock Ultra review – The fastest smart door lock?

Design & workmanship: Compact, elegant and well thought-out

The Nuki Smart Lock Ultra features a completely redesigned design that differs significantly from its predecessors. While previous Nuki models consisted of a bulky rotary knob with an attached battery compartment, the Ultra features a compact stainless steel knob that blends seamlessly into modern doors.

With a diameter of 57 mm, the Ultra is three times smaller than its predecessors, making it one of the most compact smart door locks on the market. The reduction in size was made possible by switching to a built-in battery, eliminating the need for a separate battery compartment.

The design is simple, with a brushed stainless steel finish that creates a robust and durable impression. Two interchangeable base rings in black and white are included to visually match different door colors. These are easy to attach and ensure the Smart Lock blends discreetly into the door design.

Even though the Ultra is smaller, operation remains as simple as ever. The knob can be turned manually or controlled via the central button, which performs different functions depending on the setting. Minimalist design meets clever functionality.

Installation & Setup: Simple, but with limitations

The Smart Lock Ultra differs from its predecessors in one important respect. It's no longer a purely retrofit solution that simply plugs into an existing key. Instead, the included universal cylinder is mandatory, as the Ultra mounts directly onto the cylinder.

For some, this may be a deal breaker, especially in rental apartments or with existing locking systems where all doors are opened with a single key. In these cases, customization by the manufacturer would be necessary, which would involve additional costs and waiting time.

Once you've gotten used to changing the cylinder, the actual installation of the Nuki Smart Lock Ultra is well thought out and easy to complete thanks to the detailed app instructions. The Nuki app guides you step-by-step through the installation:

1. Measuring the door and the existing cylinder (measuring card included)
2. Dismantling the old cylinder (screwdriver required)
3. Assemble the new cylinder from the enclosed modules
4. Inserting the new cylinder into the door
5. Attaching the mounting plate and the Smart Lock

Depending on the door size, adjusting the cylinder takes about five minutes. The app provides clear instructions on which components to use, so there's no room for confusion. The only criticism is that for some door sizes, the combination suggested by the app doesn't necessarily fit. In these cases, the cylinder must be adjusted manually.

It's also important to make sure that the door lock engages properly with the mounting plate. During my testing, the door lock actually came loose from the mounting plate the first time I turned it and slammed to the floor. Fortunately, there was no damage to the lock.

After installation, the Smart Lock must be set up using the Nuki app (iOS & Android). Initial setup includes:

• Pairing the Smart Lock with your smartphone via Bluetooth
• Connect to the Wi-Fi or Thread network (no additional bridge required)
• Configuration of auto-unlock, time control and user management
• Optional addition of additional accessories (keypad, fob, door sensor)

If you already own a Nuki Smart Lock, you can create a backup of your existing settings in the app and transfer them to the Ultra. This automatically transfers users, schedules, and permissions, making the switch easier.

Functions & Operation: Fast, flexible and well thought out

In addition to the classic control via a rotary knob and buttons, numerous digital control options are integrated. The Ultra particularly scores points with its high speed, direct Wi-Fi integration, and support for modern smart home standards such as Matter and Thread.

Three modes: From gentle to lightning fast

The Ultra has three different closing speeds that can be set in the app:

•  Gentle: Slow, quiet opening and closing
•  Standard: Medium speed, quieter than previous models
•  Insane (very fast): Extremely fast opening and closing, but a bit louder

Practical testing has shown that Insane Mode actually makes the Smart Lock Ultra the fastest smart lock on the market. The door was fully unlocked or locked in under two seconds.

But the standard mode is also perfectly practical. It offers a balanced ratio of speed and volume and was my preferred mode for daily use in our tests.

Also useful is the automatic mode change, which switches to the quieter Gentle mode at night, for example. Gentle mode is somewhat less noisy than the other modes, but still unlocks and locks reliably.

Auto-Unlock & Lock'n'Go

As is typical of Nuki, the Ultra offers the Auto-Unlock function, which uses a combination of GPS, Bluetooth, and geofencing to detect when someone approaches the door. The app requests the appropriate location permissions from the smartphone. In our tests, the Auto-Unlock function worked smoothly and quickly.

There's also "Lock'n'Go," a feature that automatically locks the door after a preset time. This is especially useful when you leave the house and want to be sure that the door is locked behind you. We didn't encounter any problems with this during our testing either.

App control & smart home integration

In addition to the functions already mentioned, there are further setting options in the Nuki app:

• Manual opening & closing via app
• Access management for other users (e.g. family or guests)
• Log display of recent activities
• Integration into smart home systems

Thanks to Wi-Fi, Matter, and Thread, the Ultra is compatible with Apple Home, Google Home, Amazon Alexa, and Samsung SmartThings. Thread integration enables a stable and energy-saving connection without the need for an additional Nuki Bridge.

A new keypad with "Tap to Unlock" is announced for 2025. This should make it possible to unlock the door with a smartphone via NFC or Ultra Wideband (UWB), similar to the Apple Home Key. Existing accessories, such as the Nuki Keypad 2.0 or the Nuki Fob, are also compatible with the Smart Lock Ultra.

Battery & power supply: Durable, but not replaceable

One of the biggest changes to the Nuki Smart Lock Ultra is the built-in battery, which replaces the previous replaceable battery pack. This has both advantages and disadvantages, which became apparent during testing.

According to Nuki, the battery lasts up to six months, although the actual battery life depends heavily on usage. Those who use the lock several times a day or frequently use the faster locking modes should expect a shorter battery life. The choice of wireless connection also has an impact. Bluetooth and Thread are significantly more energy-efficient than Wi-Fi.

In the test, after one month of use with up to five locking operations per day, about 90% of the battery was still left, which definitely supports the manufacturer's claim.

Charging is done via a USB-C cable with a magnetic charging connector that simply docks onto the bottom of the lock. It's similar to MagSafe on Apple devices. If the door moves while charging, the cable simply detaches if pulled too hard, without causing any damage.

While this solution is practical and secure, it does have a drawback. If you lose the special charging cable, you can't simply charge the lock with a conventional USB-C cable. If you need a replacement, you can order the cable directly from the Nuki shop for €4,90.

A full charge takes about two hours, which is hardly a problem in everyday life, as the lock can continue to be used during this time.

No removable battery – a potential disadvantage?

While the built-in battery saves space and makes the Smart Lock more compact, it also has a downside. It's not replaceable. Should the battery weaken or fail after a few years, replacement is only possible through Nuki itself.

According to the manufacturer, the battery life is expected to be 8 to 10 years, and there are plans to offer a replacement program for defective batteries. However, this decision may deter some users, especially those who prefer long-term maintenance-free operation.