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Single VS. Double Cylinder Deadbolts: Choosing the Right Deadbolt for Your Needs

Single VS. Double Cylinder Deadbolts

Selecting the appropriate deadbolt lock is critical for securing your home or business effectively. Deadbolts offer an added layer of security, making it considerably more challenging for unauthorized individuals to gain access. Within the realm of deadbolts, two primary options exist: single cylinder and double cylinder deadbolts.

In this article, we'll delve into the distinctions, advantages, and potential drawbacks of single cylinder and double cylinder deadbolts, enabling you to make an informed decision to safeguard your property effectively.

Please check out our comprehensive guide on the ways to burglar proof your home if you are interested in learning more about them.

Single vs. Double Cylinder Deadbolt: Key Differences

The primary distinction between single-cylinder and double-cylinder deadbolts lies in their locking mechanisms. A single-cylinder deadbolt necessitates a key on one side for locking and unlocking, whereas a double-cylinder deadbolt requires a key on both the inside and outside of the door to operate the lock. This fundamental difference sets these two types of deadbolts apart.

Here is a comparison list between single and double cylinder deadbolts:

Feature Single Cylinder Deadbolt Double Cylinder Deadbolt
Locking Mechanism Requires a key on the outside and a thumb turn or knob on the inside. Requires a key on both the outside and inside to lock and unlock.
Convenience Easier and faster to exit in case of an emergency as no key is needed on the inside. Provides added security but requires a key for both entry and exit, potentially slowing down emergency egress.
Security Considerations Slightly less secure on the inside. Offers enhanced security as keys are needed on both sides, making it more resistant to break-ins.
Recommended Use Cases Typically used on doors where quick and easy egress is a priority, such as residential front doors. Recommended for doors with glass panels or windows near the deadbolt. Also suitable for commercial properties and high-security applications.
Code and Regulations Often complies with building codes and regulations for residential properties. May not be permitted in some residential areas. May be required by building codes for specific commercial applications.

What is a Double Cylinder Deadbolt?

In the previous section, we explored the key differences between single and double key deadbolts. In order to know their detailes, let's delve deeper into what exactly a double cylinder deadbolt is and the pros and cons of them.

Overview of the double cylinder deadbolt

A double cylinder latch is a lockset featuring two knobs instead of the traditional single knob and thumbturn combination. With this type of lockset, two keys are required for operation. One key is inserted into the interior knob, and the other into the exterior knob.

To unlock the mechanism, both keys must be simultaneously turned in the same direction, necessitating the involvement of two individuals to operate the lockset.

Pros and cons of double cylinder deadbolt


Enhanced protection against break-ins: Double cylinder deadbolts substantially increase security by requiring a key for both the interior and exterior sides of the door. This design significantly reduces the risk of burglars gaining unauthorized access to your property. In particular, double cylinder deadbolts excel at bolstering security on doors with glass panels or windows nearby, where the absence of a thumb turn on the interior side makes it difficult for intruders to manipulate the lock.

Safe for occupants inside your home: A double-cylinder deadbolt enhances security and ensures the safety of individuals inside. This is especially valuable for young children or elderly family members with dementia. Because it necessitates two keys for unlocking, it prevents a single person from exiting independently.


Safety concerns: In emergencies like fires, evacuation may be delayed because both keys are needed to unlock the door. This can pose safety risks, so some building codes restrict their use in residential settings.

Inconvenience: Daily use can be less convenient than single-cylinder deadbolts because you always need a key to enter and exit from both sides.

Potential lockouts: If you forget or misplace your keys, you can become locked out of your own property, which can be frustrating and time-consuming.

What is a Single Cylinder Deadbolt?

After knowing the double cylinder deadbolt, let's delve into the details of single key door lock.

Overview of the single cylinder deadbolt

A single cylinder deadbolt is a type of door lock commonly used in residential and commercial properties. It consists of a key-operated cylinder on the outside of the door and a thumb turn or knob on the inside. This design allows you to lock and unlock the deadbolt with a key from the outside and easily turn the thumb turn or knob from the inside to secure or release the lock.

Pros and cons of the single cylinder deadbolt


Convenience: Single cylinder deadbolts are convenient to use because they can be locked and unlocked from the inside using a simple thumb turn or knob, eliminating the need for a key for a quick exit.

Simplicity: Single cylinder deadbolts are straightforward to operate, making them user-friendly for people of all ages, including children and the elderly.

Affordability: They are often more cost-effective than double cylinder deadbolts, making them an economical choice for many homeowners.


Security vulnerability: A single-cylinder deadbolt may provide less security compared to other lock types. For example, a potential intruder could try breaking a nearby window and then reach inside to manipulate the thumbturn and unlock the door.

Single vs. Double Cylinder Deadbolts: Using Scenarios

In this part, we will explore various scenarios to understand the practical applications of single and double key deadbolts.

Everyday home use: Single key deadbolts are the most common choice for residential homes. They are easy to use and offer a basic level of security. You can quickly lock and unlock the door from the inside with a simple turn of the thumb turn.

Exterior doors with glass panels: If your door has glass panels or sidelights, a double-key deadbolt might be a better choice to prevent burglars from breaking the glass and reaching in to unlock the door.

Minimal security needs location: If you live in a low-crime area or prioritize convenience over maximum security, single-key deadbolts are ideal for everyday residential use. They offer user-friendly access and provide adequate protection for your home in such minimal security needs locations.

Security in vulnerable locations: If your home is located in a high-crime area or if you have experienced break-ins in the past, a double key deadbolt can offer greater security. Criminals won't be able to simply reach inside to unlock the door.

Property with multiple entry points: If you have multiple entry doors to secure, you may use double key deadbolts on less frequently used doors while using single key deadbolts on doors that are used regularly for convenience.

Emergency exit: In emergencies, such as a fire or the need to exit quickly, the thumb-turn on a single key deadbolt allows for a swift exit without searching for a key.

Businesses and commercial properties: Small businesses, offices, or storage areas within commercial properties may employ double key deadbolts for added security during non-business hours.

Bonus Tip: Which Grade Lock is Best?

Deadbolt locks are categorized into three grades by the American National Standards Institute (ANSI) to indicate their level of security. Grade 1 is the highest grade and offers the most security, while Grade 3 provides the least security.

Grade 1 Deadbolt Locks

These are considered "commercial grade" locks and are ideal for high-security applications, often used in business buildings. Grade 1 deadbolts must meet rigorous standards, including withstanding 250,000 open/close cycles, a bolt extending one inch into the door frame, and enduring 10 hammer blows of 75 pounds of force without failing.

Grade 2 Deadbolt Locks

Grade 2 deadbolts are also "commercial grade" but are typically priced at a mid-level point. They are commonly used in residential properties but are not tested as rigorously as Grade 1 locks. They provide a good balance of security and cost-effectiveness.

Grade 3 Deadbolt Locks

These are the lowest grade of deadbolt locks and have the lowest security rating. Grade 3 locks only need to withstand two strikes of force and are often used as a secondary security measure on doors, such as in residential settings.

How to choose them?

For high-traffic areas within your business: Opt for an ANSI Grade 1 deadbolt lock. These locks provide the highest level of security and durability, making them ideal for places with heavy foot traffic and where security is a top priority.

For areas with lower foot traffic and residential use: Consider an ANSI Grade 2 deadbolt lock. These locks strike a balance between security and affordability, making them suitable for less frequented business spaces and residential applications.

Grade 3 deadbolt locks are classified as lower-grade locks compared to Grade 1 and Grade 2 ones. These locks are designed to offer a basic level of security and are commonly used in less critical applications or as secondary security measures.

FAQs about Single VS. Double Cylinder Deadbolts

Due to safety concerns, double cylinder deadbolts may face legal restrictions in some areas. These locks require a key for both entry and exit, potentially impeding quick egress during emergencies like fires. Local building codes often limit their use on main entrance doors in residential settings to ensure safety.

Regulations vary by location, so it's crucial to consult with local authorities or building departments for specific rules on double cylinder deadbolt use.

2. Is a double cylinder deadbolt better than a single?

Whether a double cylinder deadbolt is better than a single cylinder deadbolt depends on your specific security needs and circumstances your comfort level with safety trade-offs, and any local regulations that may affect their use. Many homeowners opt for a combination of both, using double cylinder deadbolts on doors that require added security and single cylinder deadbolts on doors for everyday convenience and safety.

3. Why use a double keyed deadbolt?

A double keyed (double cylinder) deadbolt is used for enhanced security. It requires a key to lock and unlock the door from both inside and outside, making it more resistant to unauthorized entry. It's often chosen for high-risk areas, preventing unauthorized access, and maintaining key consistency.


The choice between the single cylinder vs double cylinder deadbolt ultimately depends on your specific security needs, convenience preferences, and safety considerations.

Single cylinder deadbolts are user-friendly and are commonly used in residential settings where quick and easy exit in emergencies is essential. On the other hand, double cylinder deadbolts provide an added layer of security by requiring a key to lock and unlock the door from both the inside and outside. Whether you choose a single or double cylinder deadbolt, it's always a good practice to consult with a professional locksmith to ensure proper installation.

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Yucy, as a proficient editor in Reolink, specializes in the field of home security. Her expertise lies in providing insightful information regarding the latest advancements in security systems, surveillance technologies, and safety measures. Comment and discuss with her!