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Thursday, February 12, 2026

Single vs Double Cylinder Deadbolt Locks Compared

HomeInnovateSingle vs Double Cylinder Deadbolt Locks Compared

Making your home or business secure should be a chief priority for any property owner. Your home is your sanctuary that should be safely protected from unauthorised entry. One effective way to considerably improve security is to install high-quality, sturdy deadbolt locks on all exterior doors.

Deadbolts are designed to prevent forced entry and lock picking much better than a standard doorknob lock. But when choosing between single cylinder and double cylinder deadbolts, which type is truly the best fit for your needs and priorities?

Here, professional locksmiths from Sydney explain the key differences and pros and cons of each deadbolt lock type. By the end, you’ll know how to select the right deadbolt locks to properly protect your cherished property.

This guide will also cover cost, security, convenience, ease of use and more – to help determine if single or double cylinders are a better match for your residential property or commercial space. With all factors explored, you can choose the ideal deadbolts to maximise security.

Let’s start breaking down the differences between these two popular deadbolt styles so you can make a smart decision when upgrading your home security.

What’s the Difference Between Single and Double Cylinder Deadbolt Locks?

Constructed with a rugged 1-inch throw bolt, deadbolt locks are designed to prevent forced entry and lock picking better than a regular doorknob lock. But single and double cylinder deadbolts function quite differently.

Single cylinder deadbolts contain a keyhole on the exterior side of the door and a thumbturn on the interior side. The thumb turn allows you to manually lock and unlock the deadbolt from inside your home without needing a key. This is convenient when you want to secure doors at night but don’t want to carry keys around indoors.

Double cylinder deadbolts use a keyed cylinder on both sides of the door and contain no interior thumbturn. This means you must insert a key to lock and unlock the deadbolt from both the inside and outside of the door. There is no way to open the lock without a key.

Many homeowners find this inconvenient since you must always have your door key on hand to unlock the door from inside your home. However, the trade-off is enhanced security, as we’ll explore next.

Pros and Cons of Single Cylinder Deadbolt Locks

Offering a balance of security and convenience, single cylinder deadbolts are a popular choice for homeowners looking to upgrade exterior door locks affordably. Here are the main benefits and potential drawbacks:

The benefits:

  • Cost-effective

Single-cylinder deadbolts range from $20-$50. They’re the budget-friendly option compared to more expensive double-cylinder models.

  • Convenient thumb turn

The interior thumbturn makes it simple to lock up at night without fumbling for keys. It also allows quick exit in an emergency without tracking down a key.

  • User-friendly operation

The thumbturn is easy for young children and seniors to operate, allowing independence.

  • Quickly add extra security

Simple installation takes less than 30 minutes for a handy homeowner. Just replace your existing knob lock with the single cylinder deadbolt using a screwdriver.

The downsides:

  • Less secure

Because the interior thumbturn can be accessed by breaking glass, single cylinder deadbolts are less secure than double cylinder models.

  • Vulnerable to lock picking

The keyhole is susceptible to lock picking attacks by experienced intruders. Upgrading to high-security, bump-proof deadbolts can help mitigate this risk.

  • Thumbturn can be accidentally turned

Small children may play with the thumbturn, allowing them to wander outside unsupervised.

Pros and Cons of Double Cylinder Deadbolt Locks

If maximum security is your top concern, double cylinder deadbolts add an extra layer of protection for your home.

Here are the main advantages and disadvantages:

The benefits:

  • Improved security

With no interior thumbturn, double cylinder deadbolts prevent entry even if exterior glass is broken since the key is needed to unlock the door. It deters smash and grab break-in tactics.

  • Ideal for vulnerable doors

Double cylinder models provide excellent security for exterior doors. Especially those with glass panels within arm’s reach of an intruder.

  • High-security options

Many manufacturers offer double cylinder locks with bump, pick and drill resistant features. Upgrading security is as simple as replacing the lock.

  • Better protects outbuildings

For exterior sheds, garages and other outbuildings, double cylinder deadbolts discourage unauthorised entry.

The downsides:

  • No interior thumbturn

Lacking a thumbturn makes egress difficult in an emergency. Working smoke detectors and fire escape ladders can help mitigate this.

  • Lockout risk

For absent-minded homeowners prone to misplacing keys, the inconvenience of getting locked out without a key can definitely be frustrating. Keeping a spare key hidden outside can provide backup access if needed.

  • Higher cost

Double cylinder deadbolts range from $35-$75 or higher and are more expensive than entry-level single cylinder options. However, the security may justify the added cost.

  • Requires carrying keys

Without a thumbturn, you must carry keys whenever moving indoors near a double cylinder deadbolt door to avoid getting inadvertently locked in a room.

Single vs Double Cylinder Deadbolt Locks: Which Type is Better?

Given the pros and cons of each type, is one deadbolt style definitely better than the other? Unfortunately there is no universally “best” option, since the ideal deadbolt depends primarily on your property’s needs and priorities as a homeowner.

If quick emergency egress and convenience are your top concerns, single cylinder deadbolts would likely be the better choice.

The interior thumbturn makes navigation and exiting the home easy in an emergency, while also allowing you to secure doors at night without fumbling for keys.

For homeowners who prioritise robust home security against break-ins above all else, double cylinder deadbolts are likely the better option.

The added assurance of needing a key to open the lock even from inside often provides peace of mind worth the small trade-off in convenience.

Many homeowners strike an effective balance by installing single cylinder deadbolts on primary entry doors for convenience, while using double cylinders on vulnerable exterior doors for enhanced security. It enables you to customise security through your home.

No matter which you choose, always opt for durable deadbolt locks constructed from brass or stainless steel. Check that the bolt extends at least 1-inch when locked for optimal strength. Upgrading to bump, pick and drill resistant deadbolts where possible also boosts security.

FAQ: Single vs Double Cylinder Deadbolt Locks

What are the key security differences between single and double cylinder deadbolts?

Single cylinder deadbolts allow easy exit from the inside via a thumbturn, while double cylinder deadbolts require a key on both sides, making them more resistant to break-ins through glass doors or nearby windows.

Are double cylinder deadbolts legal in all areas?

Some local building codes restrict double cylinder deadbolts on doors that serve as emergency exits, due to potential egress risks. Always check local regulations before installation.

Can a double cylinder deadbolt prevent burglaries more effectively than a single cylinder?

Yes, because it eliminates the vulnerability posed by broken glass near the door, forcing intruders to have a key to gain entry from either side.

What type of doors benefit most from double cylinder deadbolts?

Doors with nearby windows, glass panels, or sidelights benefit most from double cylinder deadbolts, as they provide added protection against intruders reaching through broken glass to unlock the door.

Do single cylinder deadbolts increase convenience in emergency situations?

Yes, the interior thumbturn allows fast and keyless exit during emergencies like fires, making them safer for quick egress compared to double cylinder locks.

How can I balance security and convenience using deadbolts?

Many homeowners install single cylinder deadbolts on standard doors for easy exit and double cylinder deadbolts on doors with glass panels or less frequently used entrances, achieving both security and convenience.

Are there high-security options for single cylinder deadbolts?

Yes, premium single cylinder deadbolts offer features like bump-proof, pick-resistant, and drill-resistant mechanisms, providing strong protection without sacrificing interior convenience.

Can double cylinder deadbolts pose fire safety risks?

Yes, since they require a key for egress, they can delay exit during emergencies. Installing smoke detectors, escape ladders, or keeping spare keys accessible can mitigate this risk.

What materials should I look for in a durable deadbolt lock?

Brass, stainless steel, and reinforced metal alloys are preferred for deadbolts, as they resist forceful attacks and ensure long-lasting durability.

How much does professional installation of a deadbolt typically cost?

Installation costs vary depending on lock type, door material, and complexity, ranging from $50–$150 for standard doors. Professional locksmiths can ensure proper alignment and optimal security performance.

Are there smart or electronic versions of single and double cylinder deadbolts?

Yes, smart deadbolts combine traditional cylinder mechanisms with digital access via apps, keypads, or biometrics, offering remote control, activity logs, and enhanced security features.

How do I maintain deadbolt locks to ensure long-term security?

Regularly lubricate the bolt with graphite or silicone spray, check alignment, and replace worn parts to prevent jamming or decreased resistance against forced entry.

Is it safe to use a double cylinder deadbolt on a frequently used exterior door?

It can be less convenient and potentially risky in emergencies. Double cylinder locks are best for doors with minimal daily use or doors that require extra protection, such as garages or outbuildings.

Can single cylinder deadbolts be upgraded for glass-paneled doors?

Yes, combining a high-security single cylinder lock with reinforced glass or security film can protect doors with glass panels while maintaining easy interior exit.

Conclusion

Installing sturdy, high-quality deadbolt locks remains one of the most effective ways to protect your home or business from unauthorised entry. Both single and double cylinder deadbolt designs have unique advantages that suit different property needs.

Take time to thoroughly evaluate your priorities, home layout and security vulnerabilities to determine if convenience, maximum security or a balance of both is the biggest factor for your locks.

The experienced locksmiths at Clockwork Locksmiths are ready to discuss your needs in detail and help you choose the ideal deadbolt locks to enhance security across your property. Contact us today to get started securing what matters most. Our team is always available to help safeguard your property.

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Pearls of Wisdom
Ray Gioiellio
Ray Gioiellio
I am Ray Gioiello an accomplished writer known for his compelling storytelling and insightful prose. With a passion for home and improvement subject, He has captivated readers with his unique perspective and vivid imagination.
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