There’s a reason people want to equip their homes with double cylinder locks. These locks require a key to lock or unlock the door both from the outside and the inside, making them a little safer, in one regard.
For example, if there’s a window on or nearby the door – think of sidelight windows next to a door, for example – someone could break the window, reach in, and turn the deadbolt of a single keyed lock. With a double cylinder lock, they’d still need a key in that case.
So why aren’t there any smart double cylinder locks on the market?
That’s the question we received on the IoT Podcast hotline in our last episode from Scott. It’s a good question and the answer also relates to safety, but not from the outside of your home.
In the U.S. many fire codes actually don’t allow for double cylinder locks for a home’s entry door. The reason is that if you have to leave the house quickly, such as in a fire, it requires a key to unlock the door and flee the fire. What happens if you can’t find or reach the key in an emergency such as that? Nothing good of course. Sure, you can leave your key in the lock from inside the house to mitigate this, but if someone breaks a window near the door, they can turn the key as if it were the deadbolt on a single cylinder lock.
As a result, it’s really not in the interest of smart lock manufacturers to design and build a smart lock that works like a double cylinder device.
I suppose it’s possible that a lock company could eventually offer one with a keypad both on the inside and outside of a connected lock. After all, there’s no physical key to find in case of a fire or other emergency. But it’s still a potentially risky situation: If you’re facing fire or some other home emergency, will you be able to focus your mind in a life-or-death event and clearly remember your keypad code?
To hear Scott’s question in full, as well as our discussion of the answer, tune in below to the IoT Podcast:
I have been searching for this “double cylinder” smart lock in the last two months and no one offers it.
I understand the “safety” issue when fire or danger happens inside this house but in here (Australia), some insurance companies require double cylinder.
In fact, this is one of the reasons I am searching for such smart double cylinder lock since it can fulfill both safety and security (insurance requirement); imagine that the smart lock can be open from both side with fingerprint or passcode, but the inside one will be disable (i.e., unlock) during day time or when someone is at home and at night time, it is locked and requires a passcode or fingerprint. If fire happens when the inside one is locked, using fingerprint or even passcode shall be fine.
It looks like some Chinese manufacturers have something close to it but need to do more research.
https://tediton.en.made-in-china.com/product/cyBEPVDKnzWg/China-Electronic-Smart-Cylinder-Bluetooth-Lock-Unlock-by-Code-Card-and-Bluetooth-Mobile-APP.html
Another note: why are those retrofit cylinder smart locks so expensive!
The safety issue is a copout. If lock makers can and will make locks keyed on both sides there is no reason they can’t and shouldn’t make locks with keypads on both sides, smart or not.
Who says its for a front door? I’m looking for one for my gate out side so I don’t have to walk down the driveway to lock it every night. If I use what’s on the market anyone can stick their hand through the gate and turn the nob so its useless. This isn’t complicated. Make something the consumer wants. If you make a double cylinder for sale, the risk in the same.
Hey Fred,
Did you ever find something that works. It’s been a year from your comment and I am in the same situation, have a gate leading to the backyard that I would prefer to just give gardners, myself, etc codes to get in and out, but like you need a double keyed so no one can just reach in and turn it.
Still haven’t found anything.
Level Bolt, The Invisible Smart Lock
Thank you Brad, I think this is perfect for what I need.
FYI, for anyone still looking, the Nuki’s been around for a while.
https://nuki.io/en/smart-lock/
Haven’t tried it myself. Might pull the trigger soon
Has anyone found a double sided smart lock yet?
https://nuki.io/en/smart-lock/
https://www.amazon.com/gp/product/B00M8T70U4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
i need a wifi double keyless deadbolt lock for an office grill.
Leaving the key in, to get out at night makes perfect sense to me.
I have no worry about a break in when I am home (in most neighborhoods, not really a problem), I only care about the security of the lock when I am gone. Even if leaving the key in when home provides no more security than a deadbolt, it is still way more security when you are not home.
Funny thing, when the fire departments comes to our neighborhood meetings, they do tell you about the hazards of not finding a key in an emergency, when the police department comes to the meeting, they tell us a double-cylinder lock is great idea. 😁
A solution to smart double deadbolts! Had to switch my double deadbolt to kwikset from Schlage, but this works great so far. Level Bolt, The Invisible Smart Lock. Bluetooth Deadbolt, Keyless Entry, Smartphone Access, Works with Ring and Apple HomeKit https://www.amazon.com/dp/B086VQ37W4/ref=cm_sw_r_cp_api_glt_fabc_5RCG70BMYRQMRJ7SEAVM
https://level.co/?gclid=EAIaIQobChMIhIHeqrXT-QIVxB-tBh24zQKAEAAYASAAEgLqmPD_BwE
You can achieve this with Level Lock
I don’t think you can have both sides lock with a key with the Level. There is a bolt on one side.
There are two models of the Level. One, as you mention, does have a turnbolt on the inside. That one is called the “Level Lock.”
But they also make one which is just the interior mechanism and only replaces the deadbolt itself. That one is called the “Level Bolt.”
Because it only replaces the deadbolt itself, “Level Bolt is designed for most standard exterior doors and lets you keep your lock and keys the same.”
Level lists several “double cylinder“ (key on each side) compatible deadbolts on their site, such as the Baldwin Prestige series.
https://level.co/support/compatible-deadbolts
As was already mentioned in this thread, these can be particularly useful for a gate. They may not be to code for a building that people sleep in because of fire safety concerns, you just have to check with your local jurisdiction.
The main issue for most people is compatibility. Originally it only worked with its own app or Apple HomeKit. In the last year or so they have added compatibility with the ring doorbell pro using Amazon’s Sidewalk protocol, but that’s still pretty limited.
Anyway, as far as the Level goes, the first rule of home automation applies: “the model number matters.“ The level “Lock,” as you mentioned, won’t work with a double cylinder lock. But the level “Bolt” model Will work with at least some.
JD, thank you. This is great news, as I know a lot of people ask about this. Thank you!
As others have mentioned above, the Nuki might also be a candidate for readers in Europe who have a Euro profile double cylinder lock with emergency function. However, the Nuki fits over the existing lock with key and replaces it with a push button, so it’s really changing the function of the lock to that of a single cylinder.
That might be fine for those households who really just wanted to add smart lock functions to the exterior side. And especially those who always keep the key in the interior side anyway. But if for any reason you needed both sides of the door/gate to be lockable, the Nuki probably isn’t a good match.
The Level Bolt model, in contrast, still retains the original double cylinder locking functionality on both sides. Say you had a garden gate and a family member who wanders. You might have a double cylinder lock there for safety reasons. The Level Bolt would retain the original double cylinder functionality, but the Nuki would not. So you do have to go pretty deep into the details of each candidate to figure out what will be a match to your own needs.