Buying a smart lock: Retrofit your old one or replace it?

So, you’ve decided the time has come to upgrade the first layer of your home’s security—the deadbolt lock on your door—to a smart model. The next step is to decide if you should replace the entire lock, or if you should retrofit the one you already have.

Hang on, let’s back up a second. What exactly is a smart lock, you ask? It’s any door lock with wireless connectivity and a motor that enables it to be opened without a physical key—and in many cases, instead of one. Smart locks can be operated with some combination of numeric keypad, smartphone app, NFC card, via the internet, with a biometric reading, a physical key, and so on. Not every model supports every option, but if you have a broader smart home system, most can be integrated into it.

This story is part of TechHive’s in-depth coverage of the best smart locks.

There are smart locks for every major wireless standard, ranging from simple Bluetooth locks that can be operated only at close range to more full-featured Wi-Fi smart locks that can be operated and managed from anywhere in the world. Locks supporting Z-Wave and Zigbee are also available, so no matter what type of smart home ecosystem you have, you can find a lock that will fit in with it.

Some newer locks also support more modern standards like Matter, and can work with third-party assistants like Amazon Alexa, Google Home, and Apple’s HomeKit. In some cases, you might need to purchase a bridge to connect the wireless radio in your smart lock to your Wi-Fi router; in other situations, your smart home hub might serve that purpose.

How is a retrofit smart lock different from a complete replacement?

A replacement smart lock is just what it sounds like: It’s a complete mechanism that replaces your existing lock in its entirety. You’ll remove your old lock and its bolt to the point where there’s just a bore hole in your door and in its side jam.

The upside is that you’re modernizing your entire deadbolt, and you might be gaining more convenient ways to open the door (a keypad, a fingerprint reader, and so on). The downside is that you’ll no longer be able to use your existing keys to unlock the door. If you’re a renter, your landlord probably won’t like that. And if you’re a homeowner and all your locks are keyed alike, you’ll be giving up one convenience for another.

Yale

Yale

Yale

A replacement smart lock will have a pair of mechanical systems known as “escutcheons,” one on the interior side of the door and one on the exterior side. The two components connect mechanically and electrically. In most cases, you’ll pass a bundle of wires from the exterior component through the door’s bore hole and then plug it into a circuit board inside the interior component before you bolt the two components together. The interior escutcheon will also have a battery compartment that powers the entire system.

A retrofit smart lock, on the other hand, only involves replacing some of your existing deadbolt’s components, typically, just the interior escutcheon. The exterior escutcheon will remain in place. The upside is that you can continue to use your existing keys to open the door, and you won’t be changing anything about the door’s exterior aesthetic. The downside is you won’t get some of the high-tech and convenient ways to open your door that a replacement smart lock can offer.

When is a replacement smart lock best?

The primary benefit of a replacement smart lock is that it provides the user with the most flexibility about how they access the lock. Do you want a numeric keypad or a fingerprint scanner to allow not only for keyless access but for mobile access without a smartphone? Do you have young children or seniors who might not be able to operate a lock but who can hold a small access card up to the door? In each of those situations, a replacement smart lock makes the most sense, and since the category is quite large, you can shop for the device that offers all the features you want.

Replacement smart locks, especially ones with Wi-Fi support, are the device of choice for those who operate their homes as vacation rentals—through Airbnb, for example—because the owner can set time-limited and revocable PIN codes for guests and maintain access logs to ensure no one is in the unit when they aren’t supposed to be.

The ability to set different PINs that are restricted based on the time of day or day of the week can also be helpful if you have, for example, a housekeeper who you only want to enter the home on Tuesday mornings. Need to give a handyman access to fix a leak? Create a one-time PIN that expires immediately after use.

You might also find that your existing lock is incompatible with a retrofit lock. While this isn’t typical, it’s a good idea to confirm compatibility with the specific lock you want to purchase before you pull the trigger. You’ll also want to check the new lock’s specs to ensure its borehole requirements match, especially if your home is older.

Lastly, note that if you have a mortise lock—more common in Europe, but not unheard of in the U.S.—you’ll only be able to replace it with a smart mortise lock.

When is a retrofit smart lock best?

Replacement smart locks have their advantages, but they aren’t the right choice for everyone. The biggest reason you might choose a retrofit smart lock is because it allows you to keep your exterior escutcheon as is. If you rent your home, your landlord would probably bristle at a new lock being placed on the door—particularly one to which they would not have the key.

A retrofit lock lets you keep the existing external hardware—key cylinder and all—while adding mobile app access to the lock. The Level Bolt is unique amount retrofit smart locks in that it replaces only the bolt element of the lock—both the interior and exterior escutcheons get re-installed on either side of it. Still, if you’re a renter, you’d be well advised to check your lease to see if replacing even the interior escutcheon of an existing lock is allowed.

Similarly, many homes have an ornate exterior escutcheon that doesn’t just function as a locking mechanism, but that also adds decorative appeal. Smart locks have not traditionally been the most attractive devices on the market, so retrofit locks are a better choice if curb appeal is critical. (That said, the interior escutcheon of any smart lock is rarely a thing of beauty, either.)

Because they require fewer components, retrofit smart locks are easier to install, but not by a large margin. That said, you’ll still need to be handy with a screwdriver and have some patience regardless of the type of lock you choose, especially if it’s your first time installing one. Smart locks are generally easier to install now than they were a few years ago, but the process is rarely as streamlined as the manufacturers claim.

Most retrofit locks are accessible from the outside only via a mobile app—or via the original physical key—so every user will need to have a smartphone, the relevant app, and appropriate access to the lock. Many retrofit lock manufacturers, however, do offer optional accessories that can be used in addition to a mobile app.

The Level Keypad, for example, provides PIN features that otherwise wouldn’t be possible with the company’s Level Bolt retrofit smart lock. August has something similar for its retrofit smart lock, as does Yale for its brand-new Yale Approach retrofit smart lock. In many cases, you’ll find these accessories bundled with the locks, affording you a small discount compared to buying them a la carte.

Want to read additional reviews before you decide? Check out our top smart lock picks.