The Nuki 4.0 Pro locks the bolt | Long-term test

The Nuki 4.0 Pro – Key away, phone out.

The Nuki door locks have been accompanying us for several generations now, and each generation brings innovations that have their appeal. Some capabilities are only recognized when you live with them for a while, and some weaknesses as well. Therefore, we have operated the Nuki 4.0 Pro Smart Lock for a few months and documented our daily life with it. In the long-term test and especially against the background that there is now already the next appealing version, the Nuki Ultra, we noticed some things that should be relevant for the purchase.

The essential results summarized:

The Nuki Smart Lock 4.0 Pro offers a range of advantages, but also a few optimization possibilities that should be considered when making a decision. A summary of the essential points can be found below. In the detailed comparison with the Aqara U200 further down in the text, I also go into further, somewhat less decisive advantages and disadvantages of both locks.

Advantages:

• Easy installation: The mounting of the lock is uncomplicated and requires neither drilling nor screwing, nor replacing the lock, making it particularly suitable for rental apartments.
• User-friendliness: The rotating ring and button on the lock are simple and effective. The app is user-friendly designed and offers many configuration options that allow the lock to be adapted to almost any need and any door lock. Here the lock is a true test winner.
• Many smart functions: The lock offers numerous functions such as Auto-Unlock, Auto Lock, Lock'n'GO, remote access with assignment of user rights and night mode, which can be a real "game-changer" in everyday life and increase living comfort.
• Support for Matter and Thread: The compatibility with the new smart home standard Matter as well as the radio standard Thread enables seamless integration into various smart home systems and increases the future-proofing of the device.
• High security: The Nuki Smart Lock 4.0 Pro offers very high security, including end-to-end encryption and the possibility to continue opening the door with a physical key.

Disadvantages:

• Volume during operation: The opening and closing process of the lock is relatively loud, which can be disturbing in quiet environments.
• Matter integration not yet mature: Some users report problems with the reliability of Matter integration, which could be due to the still young technology.
• Relatively large: The lock is relatively wide and large, making it look somewhat bulky on the door.
• Unreliability of Auto-Unlock The Auto-Unlock function does not always work as intended. During the test period, door opening repeatedly failed to occur and sometimes delayed opening occurred when I was already in the apartment. The energy requirement through geo-location, with simultaneously deactivated energy saving mode, is also high.
• Regular charging of the battery required: Although the lock is operated with a rechargeable battery, it must be charged regularly (approx. 2x per year), which means a certain maintenance effort.

These advantages and disadvantages should be considered when deciding for or against the Nuki Smart Lock 4.0 Pro to ensure that it meets individual requirements and expectations. For completeness, we have summarized the technical data in a table below.

Technical specifications at a glance

Package contents and first impression

The package contains everything necessary for installation and operation.

Package contents:

• Nuki Smart Lock 4.0 Pro: The main device in a choice of white or black, complemented by an aluminum ring in silver.
• Nuki Power Pack: A powerful rechargeable battery that can be charged via the included USB-C cable.
• Mounting material: Various adapters for different door cylinders as well as tools for secure attachment.
• Instructions: Clearly structured and user-friendly documentation for installation and setup.

First impression:

The first impression of the Nuki Smart Lock 4.0 Pro is overall positive. The lock is already completely assembled in the package. Only the labeled insulation strips need to be pulled and you can get started. The lock impresses with its modern and robust design that makes a high-quality impression. The plastic of the mounting plates is somewhat less high-quality, but completely disappears behind the lock after mounting and serves its purpose.

The product also scores points in terms of sustainability, as the compact and environmentally friendly packaging reduces the ecological footprint.

Comparison to relevant competitors

Compared to the Aqara U200, which additionally offers a keypad with fingerprint sensor in the package contents, Nuki focuses on the core functionalities of the smart door lock and offers possible extensions as separate accessories (see further below). The integrated WLAN support of the Nuki 4.0 Pro eliminates the need to purchase a bridge. The Aqara U200, on the other hand, comes without WLAN functionality and is controlled via Bluetooth, NFC or Matter over Thread. So if you want to control the Aqara U200 remotely, you need a Matter-capable hub, which may incur additional costs ([url="https://www.produck.de/quack/4763/aqara-u200-smart-door-lock-mit-keypad-im-test-smart-modern-und-benutzerfreundlich/",name="to the detailed test",title="Test Aqara U200"]). The keypad is also required to make various settings or to verify them, while the Nuki 4.0 Pro can be configured autonomously. So there are pros and cons on both sides, which I will go into in detail further below.

Installation and setup

The installation of the Nuki Smart Lock 4.0 Pro is simple and extremely user-friendly. Thanks to the well-thought-out construction and the mounting material included in the package, the lock is attached to most doors in just a few minutes – completely without drilling and changes to the door itself. This property makes the Nuki particularly attractive for rental apartments, as it can be removed without leaving residue. In comparison, the Netatmo Smart Door Lock requires the cylinder to be replaced ([url="https://www.produck.de/netatmo-smart-door-lock-im-test/",name="to the detailed test",title="Test Netatmo Smart Door Lock"]), which means significantly more effort.

Steps for installation:

1. Preparation: The door cylinder must have an emergency and danger function so that the lock can be operated from the inside while the key is stuck outside. This way, even in an emergency (forgot your phone?!) or for family members who occasionally prefer to use the good old key, unlocking from outside is still possible.
2. Attaching the adapter: Depending on the type of door cylinder, a suitable adapter (A/B with different thickness) is selected and securely attached. This can be screwed, glued or simply plugged on and attached with the retaining screws on the door lock. The latter was completely sufficient in my case.
3. Mounting the Smart Lock: The lock is placed on the adapter and clamped tight.
4. Activation: The Nuki Power Pack is inserted, and the lock performs an initial calibration process. It tests the locking path.

Setup:

• After physical mounting, the lock is set up via the Nuki app. This guides the user step by step through the process, from the Bluetooth connection to WLAN configuration and adjustment of the locking path. Everything is explained in detail and worked without major problems in the test.
• The app then allows creating user profiles and assigning individual access rights – for example for family members, friends or cleaning staff.
• After successful setup, the lock can be controlled via Nuki app, Auto Unlock or also through voice commands using compatible voice assistants.

Integration with HomeKit

The Nuki Smart Lock 4.0 Pro offers comprehensive integration with Apple HomeKit, making it particularly attractive for users of Apple devices. The setup is uncomplicated and only requires scanning the HomeKit code that is attached to the bottom of the lock.

Setup and control

1. Setup:

   • Step 1: Scan HomeKit code in the Nuki app or directly in the Apple Home app.
   • Step 2: Assign the lock to a room in HomeKit, e.g. "Front door".
   • Step 3: After successful setup, the lock can be controlled with Siri or the Home app.

2. Control options:

   • Siri commands: "Hey Siri, open the front door" or "Is the front door locked?"
   • Automations: The lock can be part of scenes, e.g. "Good night", which automatically locks all doors.
   • Notifications: Push messages inform about the status of the lock, e.g. "Door was unlocked".

Advantages of HomeKit integration

• Easy access and control via Siri and the Apple Home app.
• Seamless integration into automations, e.g. automatic locking when activating the "Leave home" scene.
• Privacy: Communication takes place locally, which increases security.

Disadvantages and optimization possibilities

• HomeKit integration does not cover all functions of the Nuki app, such as detailed access logs.
• Setting up WLAN in HomeKit is not as intuitive as in the Nuki app.
• HomeKit requires an Apple device as a control center, which means additional hardware costs.

Security features

Naturally, Nuki places great emphasis on security, as it is an essential criterion for smart door locks. With modern encryption technologies, comprehensive user permissions, security certifications and emergency solutions, the lock offers a comprehensive security architecture that we have little to criticize.

Technical security features

1. End-to-end encryption:

   • Encryption standard: AES-256-bit, as used in online banking
   • Data protection: Communication takes place directly between smartphone and lock, minimizing potential security vulnerabilities. Data is stored locally where possible, but also on Nuki servers depending on usage/settings. The company strives to give users transparency about data usage (see following images).

     

     

2. Access control:

   • User roles: Rights can be assigned individually for different users, e.g. time-limited access for guests.
   • Access log: The Nuki app stores detailed logs so that it can be traced at any time who has used the lock.
   • Authentication: When this function is activated in the app, users must authenticate before they can open the app.
   • Warnings when opening doors: You can set in the app to receive warnings, e.g. when the lock is opened from an unknown location. Various warning levels can be set.
   • Smart notifications: The app optionally shows you when the door is not yet locked while you move away from the lock.

3. Emergency mechanisms:

   • Physical key: The key can still be used, providing security in case of power failures or technical problems.
   • Manual unlocking: The lock can be unlocked from the inside via a rotary knob.

4. Security certifications

   • Independent verification: Independent security institutes regularly test and certify the Nuki Smart Lock. For example, it received the certificate as a secure smart home product from the AV-TEST Institute in 2021.

Positive:

• Strong encryption and comprehensive data protection increase trustworthiness.
• Flexibility through user roles and ability to use physical keys.
• Detailed access logs in the app provide transparency and traceability.

Optimization possibilities:

• The access log function is only available in the Nuki app and could be extended through integration into HomeKit.
• The volume of the motor remains a potential security risk as it draws attention.
• Connected voice assistants that can be activated from outside by calling pose another risk, which is common to all devices with this functionality.

The Nuki Smart Lock 4.0 Pro convinces with a well-thought-out security architecture that offers both technical sophistication and practical solutions. In our experience, it is one of the safest options in the field of smart door locks.

Everyday usability

The Nuki Smart Lock 4.0 Pro proves to be a versatile and user-friendly device in everyday life that convinces with its intelligent technology. From daily use to extraordinary situations, the lock offers functions that we will discuss below.

Functions in everyday life

1. Auto Unlock:

   • Function: The lock automatically recognizes when the user approaches and unlocks the door. This is particularly practical when your hands are full.
   • Reliability: In the test, Auto Unlock did not always work reliably. Sometimes it was not recognized when you moved out of the geofence and thus the function became unusable (see image). Especially when walking the dog, getting food or other activities in the vicinity, I could move far out of the area. If the absence was not long enough, the criteria for Auto-Unlock were not met (despite activated access to GPS, WLAN and Bluetooth). Then it means taking out your phone in front of the front door, opening the app etc. and that really frustrated me. Without an expanding keypad, therefore no real relief for short walks. It is understandable that you don't want to make a mistake here and accidentally leave the front door open despite absence. Nevertheless, it limits the added value. Occasionally the phone only unlocked when you were in the apartment, which poses a real security risk especially at night. Especially since the test quickly showed that when activating the Auto-Unlock function with geo-location, especially when you turn off the energy saving mode for better performance, the phone battery runs out much faster.

     

2. Remote access:

   • Thanks to the integrated WLAN module of the Pro version, you have access from anywhere without additional accessories. In the test, this was particularly helpful when a family member locked themselves out, but also for spontaneous situations, e.g. when craftsmen need access.

3. Automatic closing

   • The Auto-Lock function, which automatically locks the door after a defined time after it has been opened or not locked, proved to be helpful. Time intervals between 30 seconds and 30 minutes can be set, after which the lock automatically closes again. Caution should of course be exercised so that you are not just without smartphone and key in front of the door and locked out.
     

     Another helpful function is the so-called Lock'n'Go:

     

4. Night mode:

   • The night mode ensures that the door is automatically locked at a certain time and unlocked again in the morning. This provides additional protection during the night and can be individually configured in the Nuki app.

     

5. Access control:

   • Temporary rights: Access rights with time windows can be granted via the app. For example, when cleaning staff should only have access on certain days and at specified times.

Positive:

• Diverse functions such as Auto-Unlock, Auto-Lock, night mode and remote access.
• Flexibility through individually adjustable access rights.
• Intuitive control via app and voice assistants.

Optimization possibilities:

• The volume of the motor remains a disturbing factor for nighttime applications.
• The Auto-Unlock function is not always reliable. Higher accuracy is required.
• Activating functions with geo-location increases the power consumption of the phone.

Reliability and user-friendliness of the Nuki Smart Lock 4.0 Pro

The Nuki Smart Lock 4.0 Pro convinces in the test thanks to intuitive operation and a variety of functions that appeal to both technically savvy users and beginners. High reliability when locking is also given.

Aspects of reliability

1. Response time:

   • Fast response: Commands from the app are executed in an average of 1.2 seconds via the app, the keypad is minimally faster. Complete locking on our door with double rotation took 5.8 seconds.
   • Connection stability: Both Bluetooth and WLAN connections showed no failures in the test.

2. Battery performance:

   • Longevity: The Power Pack lasted up to 6 months in the test with average use with activated WLAN.
   • Comparison in different modes:
     • Bluetooth only: 8–10 months
     • With Nuki Bridge: 8–10 months
     • Via Thread: 7–9 months
     • With activated WLAN: 6 months
   • Charge indicator: The app monitors the battery status and informs in time about a low charge level.

3. Emergency operation:

   • Manual unlocking: Even with an empty battery, the lock can be opened mechanically from the inside.
   • Alternative control: A physical key remains usable, providing additional security.

User-friendliness

The operation of the Nuki Smart Lock 4.0 Pro is designed to be intuitive and user-oriented. This is due on the one hand to the lock itself, which with the ring and the button that can start multiple functions, covers many everyday actions.

On the other hand, the app extends the possibilities in many ways. It seems very mature and offers in my opinion the best UX on the market. It is clear, clearly structured and initially somewhat text-heavy. Nevertheless, there are helpful animations where it makes sense that illustrate the process. Here Nuki has found the right balance.

Via a widget on the smartphone's home screen, the app can be opened quickly. I personally find the logo a bit too discreet (a white ring on a black background), so it stands out less among other apps and you sometimes have to search visually for a long time. When opening the app, you first see a simple main screen through which the lock can be directly opened and closed, which certainly makes sense. Via the menu, further functions such as Auto Unlock, Swipe-Actions, Smart Notifications, User Management, Access Logs and Warning Levels are then accessible. The many setting options with additional explanations promote quick understanding of the functions and leave little to be desired. In total, I got along with the app quickly and had few open questions.

Through voice commands via Siri, Alexa or Google Assistant, the lock is also easy to operate for users with limited mobility, so that a certain accessibility is given. Scenes can also be easily realized via this, e.g. lock door with "Good night".

Comparison to competitors

The Nuki Smart Lock 4.0 Pro shows an average response time in the test, but a relatively long battery life. In terms of response time, the Nuki has to admit defeat to the Aqara lock. The motor of the Aqara U200 is stronger at 2.5 Nm, but requires more energy. The Nuki, on the other hand, is somewhat slower with a torque of 1.4 Nm, but has the longer endurance. The Netatmo without motor is naturally clearly ahead in the comparison of battery life…

Positive:

• Reliable performance without connection drops or delays.
• Intuitive control that requires no technical prior knowledge.
• Well-thought-out emergency operation with physical key and manual unlocking.

Optimization possibilities:

• Faster response times
• A stronger motor for stiff doors and for faster unlocking
• A more distinctive app logo

Comparison Nuki 4.0 Pro vs. Aqara U200

In the following comparison, I go into the advantages and disadvantages of the Nuki 4.0 Pro compared to the Aqara U200, which in my opinion is currently the biggest competitor.

Common functions

• Auto Lock: Both locks can automatically lock the door after a set time.
• Auto Unlock: Both recognize when the user approaches and unlock automatically.
• Integration into smart home systems: Both Nuki and Aqara support Apple HomeKit and other platforms.

Important differences in everyday life

• User-friendliness:

  • The Aqara U200 offers a better hardware experience in everyday life: The fingerprint scanner works reliably and quickly, so this is usually the primary method. HomeKey is often used as a backup.
  • With the Nuki 4.0 Pro, the fingerprint scanner is perceived as cumbersome, and the keypad is less intuitive.

• Ecosystem:

  • Aqara integrates additional devices like motion sensors or indoor buttons seamlessly into its own ecosystem.
  • Nuki remains limited to its own app, which reduces flexibility, but offers more software functions.

• Future prospects:

  • Aqara plans to equip HomeKey with UWB support, which could enable automatic unlocking like in cars.
  • Nuki has promised many features (e.g. HomeKey), but has not implemented them so far.

Interim conclusion

The Nuki 4.0 Pro scores with mature software functions and comprehensive smart home compatibility. The Aqara U200 convinces with advanced hardware and a fast, precise fingerprint scanner that is easier and faster to use in everyday life. The choice ultimately depends on personal priorities – whether more value is placed on software flexibility or hardware performance. It should also be noted that Nuki already has another iron in the fire – The Nuki Ultra comes with some advantages, including faster response time, more compact design and quieter locking mechanism.

Price-performance ratio

The Nuki Smart Lock 4.0 Pro moves in the upper price segment, but offers an acceptable price-performance ratio through its functions, processing and integration.

In comparison to competitors like the Netatmo Smart Door Lock or Aqara U200, Nuki doesn't have to hide in terms of price. Although it is more expensive than the Aqara U200, it already has the WLAN module integrated. The Aqara U200, however, comes with keypad + fingerprint sensor from the factory and is still around 40-60 euros cheaper. In direct comparison, I would therefore attest the Aqara to have the somewhat better price-performance ratio. However, it is crucial here which functions are relevant for you, so under certain circumstances the Nuki 4.0 is the better choice.

Acquisition costs

The Nuki Smart Lock 4.0 Pro costs around 269 euros in the official shop , while the street price is 210-250 euros. This model includes the Power Pack and the integrated WLAN module, eliminating the need for an additional bridge. In comparison:

• Netatmo Smart Door Lock: Around 289 euros, but without WLAN bridge or battery, which causes additional costs.
• Aqara U200: Around 179 euros, but only fully usable in combination with a hub.

Additional costs

• Batteries or battery: The included Power Pack makes further acquisition costs unnecessary for the Nuki. Alternative models like the Netatmo Smart Door Lock require AA batteries.
• Accessories: Optional accessories like the Nuki Keypad 2 (approx. 150 euros) or the Nuki Fob (approx. 50 euros) increase flexibility, but are not absolutely necessary. The combination of Nuki 4.0 Pro and Keypad 2 currently costs 309 euros at [url="https://www.tink.de/p/nuki-smart-lock-4-pro-plus-keypad2",name="tink",title=""].
• Spare parts: A Power Pack as replacement costs around 49 euros. With Netatmo, replacement keys may be necessary, which are also cost-intensive. The Aqara U200 sometimes requires an M3 Hub, which costs around 100 euros.

Cost comparison to current competitors

The Nuki Smart Lock 4.0 Pro is priced between its competitors, but offers lower additional costs in the long term through the integrated WLAN module and the long-lasting Power Pack.

Positive:

• No need for a separate bridge saves costs and simplifies setup.
• The Power Pack is more environmentally friendly and reduces long-term operating costs.
• Good price-performance ratio compared to competing products.

Optimization possibilities:

• A complete package including Keypad 2 would make sense, but can be purchased at [url="https://www.tink.de/p/nuki-smart-lock-4-pro-plus-keypad2",name="tink",title=""].
• Accessories like the Keypad 2 or the Fob are priced too high compared to the competition's equipment.

Conclusion of the Nuki 4.0 Pro test

The Nuki Smart Lock 4.0 Pro is a well-thought-out solution for smart home users who appreciate comprehensive software functions and easy integration. With support for Siri, Google Assistant and Alexa as well as an integrated WLAN module, it offers maximum flexibility without additional hardware like a bridge. Particularly noteworthy are the temporary access rights, Airbnb integration and comfortable control via app, Apple Watch or web interface.

However, the Nuki shows weaknesses in the hardware area: The fingerprint scanner is slower and less precise than competitors like the Aqara U200, and the volume during operation can be disturbing. The keypad is also less intuitive. Although the announced HomeKey function would be a plus, it is not yet available.

The Nuki 4.0 Pro is ideal for tenants, families and landlords who prioritize smart software, while users who rely on fast and quiet hardware should consider alternatives like the Aqara U200. It will also be interesting to see how the successor, the Nuki Ultra, performs. Previous voices report numerous optimizations that address major weaknesses of the 4.0 Pro.

More information and purchase options can be found in the official Nuki shop .

You can find the lock among others on Amazon:

[asin="B0CJYH87JC",type="standard"]

Relevant questions about the Nuki 4.0 Pro

• help

  How does the Auto-Unlock function work?

  The Auto-Unlock function recognizes your smartphone when you are near the door and unlocks it automatically. Geofencing technology is used to ensure that the door is only unlocked when approaching.

• help

  Can the Nuki 4.0 Pro be used without a bridge?

  Yes, the Nuki 4.0 Pro has an integrated WLAN module and does not require an additional bridge. All functions can be controlled directly via the app or voice assistants.

• help

  Is the lock suitable for tenants?

  Yes, the Nuki 4.0 Pro is particularly suitable for tenants as it is mounted without modifications to the door. It can be removed without leaving residue when you move out.

• help

  How long does the battery of the Nuki 4.0 Pro last?

  The battery of the Nuki 4.0 Pro lasts up to six months with average use. The battery status is displayed in the app and you are informed in time about a low charge level.

• help

  Which smart home systems are supported?

  The Nuki 4.0 Pro is compatible with Apple HomeKit, Google Assistant, Amazon Alexa and other common smart home systems. Additionally, it supports API and MQTT integrations for developers.