Comparing a Double- vs. Single-Cylinder Deadbolt Lock: Is One Better for Your Home?
Level up your security with these deadbolt options
Highlights
A single-cylinder lock features both a key slot and thumb-turn
A double-cylinder lock has a key slot on both sides
You may prefer a mixture of both types of locks in your home
When making decisions about the security of your home, deadbolts might not get the attention they deserve compared to other measures, like security systems. While these systems can be a highly protective addition, a proper deadbolt can also protect you and your family.
Deadbolt locks are some of the first lines of defense for our homes, but if you’re shopping around for some, you might quickly realize not all deadbolt locks are equal. Single-cylinder and double-cylinder deadbolt locks may sound like the same thing, but they each offer a unique security function and may be better suited for certain parts of your home.
What’s the Difference Between a Double- vs. a Single-Cylinder Deadbolt Lock?
There are numerous differences between a double-cylinder versus a single-cylinder deadbolt lock:
| Type of Difference | Double | Single |
|---|---|---|
| Operation | Two key slots | Thumb-turn and key slot |
| Cost | More expensive | Less expensive |
| Ease of Use | More difficult | Easier |
| Ideal for | Entryways Back doors | Universal usage |
| Building Code Restrictions | Possible | Rarely |
Differences in Operations
Comparing double-cylinder deadbolt locks versus a single-cylinder option means looking at not only the features of each one but where each one might work best in your own home. One of the biggest differences is how each one operates.
Locking Mechanism
A single-cylinder deadbolt is probably what you’re most familiar with in your home, and it’s the most common type of deadbolt found in homes. It has a key slot on one side (usually the exterior) and a thumb-turn on the other (typically in the interior)—the single-cylinder locks by twisting the thumb-turn into place.
Double-cylinder deadbolt locks have key slots on both sides, so you use a key whether you’re accessing from the exterior or interior of the home. You must have a key for unlocking the double-cylinder on the door's interior and exterior sides.
Ease of Use
Because of the thumb-turn, a single-cylinder deadbolt may be more straightforward for some family members to use versus a double-cylinder requiring a key turn for both sides. If you decide which door you should place a single-cylinder versus a double-cylinder deadbolt lock on, you may want to consider who will access it the most and if it’s easy enough to operate.
Cost
Because the single-cylinder deadbolt depends on a thumb-turn on one side and a key on another, it’s much more cost-effective than the double-cylinder configuration. This is another factor you may consider as you plan which doors in your home will have each configuration.
Differences in Security Levels
Both a double-cylinder and single-cylinder deadbolt lock offer added security to your home, but the level of security differs between the two.
Placement in the Home
Single-cylinder deadbolts offer additional security, but not as much as the double-cylinder because of its easier use with the thumb-turn. Because of this, a homeowner will need to think strategically about where to place a single-cylinder deadbolt. It’s best to avoid placing it near a window since a would-be burglar can break a window and quickly turn the lock. They work best where you need more convenient access and away from windows, such as with a bedroom or bathroom door.
The placement of a double-cylinder deadbolt lock also depends on the door location. These locks offer higher security since someone needs a key for access on both sides of the door. This is better suited for doors near windows, or anywhere you need a higher level of security.
Emergency Situations
One major drawback to a double-cylinder lock is the potential safety hazard it causes in an emergency. As you can imagine, if you need a quick exit and a key for unlocking the door on both sides, it can cause delays when time is of the essence. It’s also easier to get locked out of your home with a double-cylinder deadbolt since you need a key to open it on either side.
Local Building Codes
Because double-cylinder locks are not a safe option for emergency exits, they’re not allowed in some jurisdictions, including within a city, state, or local building code enforcement. If you’re unsure of the fire codes where you live, check with your local regulations before installing a double-cylinder lock throughout your home or rental property, or contact a local locksmith near you for guidance.
Frequently Asked Questions
You might assume that having two locks on one door will offer more protection than only one lock, but there may not be an advantage. While there’s nothing wrong with having two locks if you feel it’s best for your living situation, rest assured having one high-quality deadbolt installed correctly will offer a high level of protection.
A keypad deadbolt, a lock requiring a code entered on a keypad entry, can be a convenient option for families with children coming in and out and needing access to the home but may not be comfortable keeping up with a key. It can also offer an easy solution if you rent your home out since you can easily change the code as needed. So, depending on your home entry’s needs, a keypad deadbolt may be worth the extra expense.