What Is A Double-Cylinder Deadbolt? (Find Out Now!)
Without sturdy, functional doors and windows, a home or commercial property isn’t secure. A door, in particular, can be manufactured with security in mind, and it can also be equipped with components that make it secure without compromising visual appeal.
One of these components is the double-cylinder deadbolt, and here this mechanism will be described in detail so the reader knows whether or not this kind of deadbolt is perfect for them.
A double-cylinder deadbolt is a type of lockset that utilizes two knobs instead of the single-knob and thumb-turn combination. Two keys are required to unlock a double-cylinder deadbolt, meaning this lockset requires two individuals for operation. Two downsides of this deadbolt type are it’s inconvenient and more expensive than a single-cylinder system.
The Double-Cylinder Deadbolt Explained
A double-cylinder lockset requires two keys. One key is inserted in the interior part of the system while the other is inserted in the exterior part. For the locking mechanism to be released, both keys must be turned in the same direction and at the same time, making this a lockset that requires two individuals to operate.
Double-Cylinder Lock Components
The components listed below are the fundamental components which all double-cylinder systems include:
- Cylinder (Tumbler)
- Exterior Knob
- Interior Knob
- Bolt/Latch
- Latch Assembly
Lock Grading System
Before purchasing any kind of lock, it’s good to be aware of the American Nation Standards Institute’s (ANSI) lock grading system. Three components make up the system, and they’re: material strength, latch length, and durability. A grade-one lock is of the highest quality whereas a grade-three lock is the lowest quality.
- Grade 1: Locks of this grade can withstand a million cycles as well as 10 blows of 75-pound force.
- Grade 2: These locks can withstand up to 800,000 cycles and five blows of 75-pound force.
- Grade 3: These locks also can withstand up to 800,000 cycles, but they can only withstand two 75-pound blows. For this reason, locks of this quality are often only used as a supplemental measure of security.
Pros & Cons of Double-Cylinder Deadbolts
Double-cylinder deadbolts are certainly not as common as single-cylinder ones, but that doesn’t mean these deadbolts have no place in modern homes. In fact, double-cylinder deadbolts provide a lot of benefits beyond the obvious security-related ones, and these benefits—along with the downsides—will be discussed in the following sections.
Pro: Discouraging a Break-In
A single-cylinder deadbolt provides security to a certain extent, but if you have one of these on an ornamental door—one which features glass panels—the deadbolt can be disabled by smashing the glass and unlocking it on the interior side of the door.
Such a situation is not possible with a double-cylinder deadbolt, as the door cannot open without two keys turning at once. If an intruder approaches your home, they will think twice before damaging your property, realizing they won’t be able to penetrate a double-cylinder deadbolt without brute force that’s sure to be loud.
Pro: Keeping Young Children, Pets, and the Elderly Secure
Whereas a single-cylinder deadbolt only keeps individuals out, a double-cylinder deadbolt keeps individuals inside safe as well. For example, if you have young children or loved ones that suffer with dementia, a double-cylinder deadbolt is ideal.
Since two keys are required to unlock the lockset, a single person wouldn’t be able to get out on their own. A double-cylinder deadbolt can even be applied to sliding glass doors and windows as well.
Pro: Goes Well With Any Decor
Since double-cylinder deadbolts have the same knob on either side, this gives them a slight edge stylistically over single-cylinder deadbolts. Therefore, if you’re someone who really cares about all the decor and fixtures in your home going together, it’s probably best to buy a double cylinder deadbolt.
You’ll get simplicity with heightened security—two qualities that often don’t go together. And while most deadbolts are made of stainless steel, there are plenty of finishes available, so customization is possible. In short, the double-cylinder option is ideal for those who care deeply about their decor.
Con: Inconvenient
When compared to a single-cylinder deadbolt, it’s clear that the double-cylinder option is a lot more inconvenient. Having to have two people there to open the door is definitely a hassle, and for both people involved.
Before purchasing a double-cylinder deadbolt, you should weigh how much you value convenience against how much you value home security. If you think that the two-person operation requirement isn’t a big deal, then go ahead and purchase a double-cylinder deadbolt to enjoy its security.
Con: Key Breakage & Misplacement
Since there are more mechanisms and components in a double-cylinder deadbolt, these systems are more prone to breaking than their single-cylinder counterparts. Additionally, since a double-cylinder system requires two keys, there’s a chance that either, or both, of the keys break, rendering the lock inoperable.
There’s also the more likely scenario of an individual losing one of the keys that’s required to open the door. It’s not to say these problems couldn’t happen with a single-cylinder deadbolt, but with a double-cylinder deadbolt it’s twice as likely that breakage or misplacement render the lockset inoperable.
Con: Price
Double-cylinder deadbolts are more expensive than single-cylinder systems, but they’re cheaper than keyless locking systems. The higher price is attributed to more materials being used, and the two-keys system is also more costly than a single-key option.
Additionally, installation could take longer for the double-cylinder lockset. One can expect to pay between $50 and $100 for a double-cylinder deadbolt, with nicer models being more than $100.
Single Cylinder vs. Double Cylinder
The main difference between a single-cylinder deadbolt and a double-cylinder deadbolt is that the latter requires two keys to function whereas the former only requires one. It’s this difference that leads home and business owners to select one kind of deadbolt over the other.
A lot of businesses can make use of the extra security that’s provided by a double-cylinder deadbolt, but most homeowners, on the other hand, prefer the convenience of the single-cylinder system.
Single-cylinder deadbolts are used commonly by homeowners throughout the United States because they are practical, affordable, and convenient for everyday use. The thumb-turn mechanisms these locks employ make them all the more convenient, but just because this mechanism is convenient doesn’t mean it’s insecure.
The downside, of course, of a single-cylinder deadbolt is that it isn’t as secure as a double-cylinder deadbolt. After all:
- The mechanism can be unlocked with tampering.
- A single-cylinder deadbolt can easily be pushed through with force.
- A young child can activate the thumb-turn and get outside without any adults being aware.
Related Questions
Since double-cylinder deadbolts aren’t used often, many individuals have questions about them. Some of these are answered below.
What are some popular double-cylinder deadbolt models?If you’re thinking of installing a double-cylinder deadbolt, here are some good options to consider:
One can use a double-cylinder lock hundreds of thousands of times without ever experiencing a problem. However, with these locks, a problem is twice as likely to occur, as two keys are required.
Are double-cylinders illegal in some places?Double-cylinder deadbolts are prohibited in some places for fire safety reasons. Essentially, individuals can get trapped in a house during a fire, or another kind of emergency, if the keys to the double-cylinder deadbolt aren’t there.
It’s important to check the local codes in your area to know whether or not you can install a double-cylinder deadbolt.
Final Note
In the end, double-cylinder deadbolts are great options for home and business owners who like to feel safe and secure. This security does come at the cost of convenience, but this is really the only significant downside of a double-cylinder system.
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Matt loves everything DIY. He has been learning and practicing different trades since he was a kid, and he's often the first one called when a friend or family member needs a helping hand at home. Matt loves to work with wood and stone, and landscaping is by far his most favorite pastime.
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