How to install a smart lock on an existing deadbolt – and why this model is my top pick

ZDNET’s key takeaways

• The Nuki smart lock is now available for $159 on its own, and $229 when combined with the Keypad 2.
• This smart lock fits into an existing deadbolt, supports Matter for easy integrations with smart home systems, and features hands-free unlocking.
• Though innovative, the Nuki smart lock requires a subscription for full remote access; it’s also very loud when locking and unlocking, and the Keypad 2 is somewhat slow.

I’m all for smart home technology, but I can understand that many people don’t share my views. Though I’m currently embracing all the ways I can live like a Jetson, I also understand that many folks are hesitant about introducing robots and AI-powered tech to their homes for how they change your lifestyle.

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If you’re a smart lock skeptic, the Nuki smart lock I tested is a low-fuss solution that might make you reconsider. This cylindrical-shaped smart lock fits on your existing deadbolt’s inner mechanism, so it doesn’t change your door’s external appearance or remove the ability to use your physical key to unlock the door. 

To set up the Nuki smart lock, you remove your traditional deadbolt’s thumb turn and replace it with the Nuki. It even includes tape to put over your deadbolt’s external part so it doesn’t fall while installing the retrofit smart lock. It’s a simple installation process that requires no handyman skills. 

Setting it up on the app is just as easy as pairing your smart lock, and using it doesn’t even require an account. 

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The Nuki smart lock is loud when locking and unlocking, which isn’t great. There’s always a whirring sound whenever you use the lock, letting most people in the house know when the door’s been locked or unlocked. I don’t care for a loud smart lock, simply because it sounds old-fashioned, but the sound isn’t a deal-breaker.

Maria Diaz/ZDNET

Each lock includes a cable to recharge the Nuki. When the battery runs out (which Nuki says should be up to a year), you don’t have to remove it or take the lock apart to recharge it. Just plug the cable into a nearby outlet and connect it to the lock using the magnetic port to recharge its battery.

You can also use hands-free unlocking through geofencing to have your Nuki unlock your door when your smartphone connects to it via Bluetooth. The Nuki smart lock also offers auto-lock at predetermined times, though it doesn’t wait until the door is closed to lock — you’d need to buy a separate door sensor for that. 

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The Nuki smart lock supports Amazon Alexa and Google Home out of the box, but it also supports Matter, which lets you easily connect it to other smart home automation systems, like Apple HomeKit. 

Maria Diaz/ZDNET

I tested the Nuki smart lock for a few days before adding the subscription. Unfortunately, I’m not a fan of paying monthly fees after spending a couple of hundred dollars on a product, especially when other smart locks offer most of Nuki Premium’s subscription offerings for free. 

Not having remote access isn’t inconvenient for most people’s everyday use, but it can be troublesome if you need to let people into your home when you’re away. Many users like having remote access to let in guests, dog walkers, cleaners, and even younger family members, but you’d have to work around this if you want to bypass the subscription.

The Nuki Keypad 2 supports passcodes and fingerprint unlocking.

Maria Diaz/ZDNET

You could pay extra to add on a Keypad and give visitors a temporary access code, but be mindful that this would still not give you remote access. 

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Nuki offers an introductory perk of a free lifetime subscription for users who sign up for Nuki Premium before September 30, which is worth signing up for.

ZDNET’s buying advice

The Nuki smart lock is designed to fit seamlessly with existing deadbolts, making it a good option for renters and homeowners who don’t like the look of a smart lock on their exterior door. However, it’s also perfect for smart lock skeptics and tech-averse folks, as you can add the perk of a smart lock without forgoing your existing physical key.

You can also set up your Nuki Smart Lock without creating an account, so it’s also a good option for privacy-conscious users. However, the Nuki smart lock is comparatively expensive when you consider adding a Keypad for external operation and a subscription for remote access, making it less than ideal for anyone on a budget.