16 Different Types of Exterior Door Locks

A close look at a white armored front door with heavy-duty locks.

In today’s world, it is more important than ever to be safe instead of sorry. One way to protect your home or business, along with yourself and those you love, is exterior door locks.

Millions of homes and businesses are broken into each year throughout the world and to help prevent that from happening to you and your property, you will need door locks that you can depend on but there are many different types to choose from. To learn which locks may be best for your situation to keep you and your property safe, here is a list of different types that are currently on the market, the features of each one, and the history of each type of lock.

Knob Locks

A close look at a white door with a knob lock.

If you have ever locked a door that leads to the outside, then you have used a knob lock. This is the most common type of door lock and it is used by pretty much everyone to lock up their home or business on a daily basis. The main feature of knob locks is that the lock cylinder is inside the knob instead of the door.

Many people use them on exterior doors along with interior ones but they are best used inside as they do not offer as much security as other types of exterior locks. A knob lock on an exterior door can be broken into easily which is the reason they are not the best choice but they work wonderfully to lock up an office door or the door to your bathroom. Here are four different kinds of knob locks that are used for interior and exterior doors and can provide enough security to be used on exterior doors.

Many door knob locks feature a keyed entry lock system that is made of stainless steel or other stronger materials that add more security. Most of these types of locks can be installed easily and quickly. Really the only equipment you need to be able to install a knob lock is a Phillips head screwdriver and many are touted as a great option for exterior doors where keyed entry is required to enter. This is a good option for your apartment, mobile home, house, garage, or business.

Knob locks have been around since the 1800s with the first patent being given to Osborn Dorsey in 1878. He was an African American inventor who came up with the creation of a doorknob with an internal door-latching mechanism. In 1818 in Britain, Jeremiah Chubb, Joseph Bramah, and Robert Barron worked as locksmiths and created the design for a tumbler lock that the modern knob locks of today are based on.

Some of the knob locks available today offer Smartkey security that you can re-program if needed. They also offer Microban protection which keeps the doorknob area up to about 99 percent cleaner than unprotected knobs. Knob locks are also available in a package with a deadbolt lock for added protection for your exterior door.

Deadbolt Locks

A look at a green door with deadbolt lock.

Deadbolt locks are by far the most popular exterior door lock and they are the most often used locks on exterior doors to residential properties. They are so popular that commercial property owners also use them to ensure security for their businesses or buildings.

Most homeowners choose a deadbolt lock with a single-cylinder which can actually be listed under a subset outdoor light types. There are many types of deadbolts that can be used in some way to secure entry to a house. This type of lock is most often used to secure exterior doors but can also be used inside of your house, although there are better door lock types for use indoors.

The deadbolt lock got its name for the fact that it does not have any spring-loaded mechanisms inside to work the bolt like other locks do so it is referred to as “dead.” The history of deadbolt locks can actually be traced back to the 1800s when banks begin using locks that required keys to protect their safes.

Back in those days, bank robbers viewed safes inside a bank as easy money to steal so the deadbolt was created to make it harder for the lock to be smashed and for the robbers to gain access to the money inside. Deadbolt locks are sometimes referred to as jimmy proof locks and those were first created by Samuel Segal, who once worked as a New York City police officer, in 1916.

He holds over 25 patents including several for different types of locks. Jimmy proof deadbolt locks are even more secure and are used often in large apartment buildings or other larger buildings for the added security they bring to the property owners.

Cylindrical Lever Locks

A cylindrical lever lockset from Home Depot.

Source: Home Depot

Cylindrical lever locks are very similar to deadbolts in the way that they operate and are also used in both commercial and residential properties to secure exterior doors. There seems to be more space on larger doors for this type of lock which is the reason they are used for securing exterior doors at businesses, factories, and large buildings. Cylindrical lever locks are easier to operate than deadbolts because the lock lends itself to easier flexibility when moving in and out of the doorway jam.

This type of lock is not as secure as a deadbolt lock so it is used less often to secure the doors of people’s homes. The lever itself can be manipulated easier, hence giving a person who is up to no good a better chance of gaining entry to the property.

Single-Cylinder Locks

This is a close look at an exterior door with a single-cylinder lock.

Single-cylinder locks have a space for a key on one side only. The other side has a twist knob that locks the door from the other side. The key side is on the external part of the door, while the internal part has the knob so that you can lock your door from the inside without a key. Single-cylinder locks can be deadbolt locks as well.

Double Cylinder Locks

A close look at an exterior door with a double-cylinder lock.

Double cylinder locks do not have a twist knob and require a key on either side. These locks are recommended for places where you don’t want anyone to be able to lock the door from the inside without a key.

Mortise Locks

A look at a brown door with mortise lock.

Similar to cylindrical lever locks, mortise locksets are also used more often on the exterior doors of businesses and other commercial properties because of the way they are designed. They need more room to operate properly but many homeowners use them to secure their homes too. Many older homes already had mortise locks in place when the homeowner bought the house and the person decided to continue to maintain the mortise locks instead of changing them out for a different type of lock.

People have been using mortise locks since the eighteenth century to secure their exterior doors to their properties in the United States. The earlier versions of the mortise locks featured a pull that allowed the door to be unlocked. The pulls were eventually replaced by doorknobs.

The intricate parts of mortise locksets are installed inside the door and include the lock cylinder and the cam which allows the door to be locked and unlocked. This type of lock is extremely strong which is why many business owners prefer it as compared to other types of locks. Mortise locks are as strong and durable as deadbolt locks and many consider them to be even more reliable than deadbolt locks. They are a great choice when it comes to security.

Euro Cylinder Locks

A close look at a Euro Cylinder lock with a set of keys.

Euro cylinder locks are used in Europe more often than in the United States, hence the name of the lock, but that does mean no one in America uses them. You will be able to find some throughout the country being used most often on patio doors or for interior double doors. Although Euro cylinder locks are used on patio exterior doors most of the time, they are not the most secure option to protect your home or business.

The body of this type of lock is more easily damaged and can break down after being used over periods of time. You may know someone that has a patio door that is hard to open or nearly impossible to lock or unlock and this is the reason for the issues. The lock body can even snap, leaving your home completely unprotected.

Even though Euro cylinder locks are not the greatest option when it comes to home security, many homeowners still prefer them because they are very easy to install and to use. They are self-contained locks which makes the installation process much easier than the process is when it comes to other types of locks. But even though it’s easy to install, it may not be the right choice for your exterior doors that are meant to protect you and your family.

Electronic Locks and Smart Locks

A close look at a brown door with a Smart Lock installed.

Electronic locks are most often used for residential properties by homeowners and the owners of condos or renters of apartments. Electronic locks are not the same as smart locks, even though people tend to lump them in the same category. Even though smart locks are electronic, not all electronic locks are smart locks.

Obviously, the two are very similar but when it comes to electronic locks, they do not have the capability for easy access that many people enjoy with smart locks. When it comes to both types of locks, though, there can be an issue when the electricity goes out due to a storm or some other issue. Homeowners and business owners should be aware of this issue and purchase an electronic or smart lock that can be backed up to have the ability to unlock it with a key if the need arises.

Most people use smart locks because of the need to have more control over the security of their home or business. The smart lock needs to have an authorized device to be able to lock and unlock it while an electronic one is usually controlled by punching in a code on a keypad.

The smart lock is controlled by wireless communication between an authorized device while the code for an electronic lock is entered manually by the person locking or unlocked the exterior door to leave or gain entry.

Both types of locks function inside the door similar to other locks, including euro cylinder locks, deadbolts, and mortise locksets. Due to their unique features, though, electronic and smart locks are in a category of their own.

Fingerprint and Retinal Scan Door Locks

A close look at a glass door with a fingerprint scan door lock.

Convenient to use because they require no key, fingerprint door locks provide a more state-of-the-art type of security because only individuals who have had their fingerprints programmed into the lock can “open” the lock. To open a fingerprint lock, a person must place their forefinger flatly on a sensor that recognizes their fingerprint pattern.

Retinal scan door locks are probably the most advanced type of exterior door lock. Predominantly used to secure buildings harboring manufacturing, medical and governmental secrets, retinal door locks require users to input a biometric scan of their retina into the lock system before gaining entry. Real-time retina scans must match what the system has on file.

Fail-Secure Electric Strike Locks

Electric locks need an electric current at least 12 volts or higher to work properly. Also referred to as a “fail-secure” device, electric strike locks ensure doors remain locked during power outages. Doors equipped with fail-secure electric strike locks also have doorknobs in case someone needs to open it from the inside of a room.

Fail-Safe Electric Strike Locks

While fail-secure electric strike locks remain locked during power outages, fail-safe electric strike locks can be unlocked during power disruptions. When integrating this kind of lock in a security system, make sure you have some type of back-up power to avoid compromising the security of a home or business.

Magnetic Locks

A close look at a dark brown door with a magnetic lock.

Magnetic locks not constructed of interlocking parts nor do they need keys or combinations to be opened. They work using magnetism powered by a 12 to 24 volt DC current. Magnetic locks are considered fail-safe types of locks because they need a live current to prevent unlocking of doors. When a magnetic lock is installed on the main entrance door, a back-up power supply is advised in case of power disruptions.

Keypad Locks

A close look at a glass door with a keypad lock.

Keypad locks rely on an electronic keypad that needs to be manually inputted with a specific linear combination of numbers, letters, or symbols in order to “tell” the lock to open a door. Keypad locks are convenient to use when multiple people consistently enter a building throughout the day. With no keys to worry about, the risk of losing keys and having them frequently replaced is eliminated.

Sliding Door Locks

A set of glass doors with sliding door locks.

Burglars consider homes with sliding glass doors as easier targets to rob. Standard sliding glass doors come with factory locks that do not provide the kind of higher security level you need. Homeowners with sliding glass doors should consider replacing factory locks with either two-bolt locks or smart locks designed specifically for these doors. Two-bolt locks strengthen door frames by sliding a steel bolt into frames while smart locks can be remotely activated from outside or inside a building.


A close look at a chain link fence locked with a padlock and a set of chains.

Padlocks have been around for years and are probably the most recognized lock by most people. They can be used for a multitude of things, including locking exterior doors, locking a shed, locking up bicycles, to secure a garage door, for added security at homes and businesses, the list is endless. Padlocks have been discovered that were actually used during the Roman Era which was 500 BC to 300 AD, so a really long time ago.

Padlocks are most often used as an auxiliary addition to increasing the security there is already in place, especially when it comes to exterior doors. Many factories and other businesses use padlocks in conjunction with other types of locks for the added security it brings to their business and the valuable items inside. Padlocks have evolved and changed a lot over the past few decades but have still maintained their integrity as some of the most dependable locks on the market.

Remote Control Lock Systems

A close look at a remote control door lock system.

A completely automated security system that allows you to unlock or lock all doors while in the shower, lying in bed or watching TV. You can also check to make sure all doors are locked from one area in a building, eliminating the need to walk through a home or business to check each door. Benefits of “keyless” remote lock systems include:

  • Ability to the preset engagement of door locks at certain times using a smartphone app
  • Connecting floodlight operations to the system so that lights turn on when you unlock a door
  • Makes it easier for people with physical disabilities to lock and unlock doors
  • Reduces home or business security costs by eliminating the need for maintenance of physical locks or replacement of damaged locks

Grading Scale of Door Locks

The American National Standards Institute (ANSI) uses a scale to grade performance and security abilities of all types of locks. Grade 1 locks are commercial level locks that are strong but more expensive than grade 2 or grade 3 locks. Locksmiths carry grade 1 locks but most hardware stores do not carry grade 1 locks.

Grade 2 locks include most exterior door locks found in home improvement department stores. Their ability of grade 2 locks to secure doors depends on several factors, such as what kind of door they are securing and materials used to make the lock.

Grade 3 locks are not as strong as grade 1 or grade 2 locks and should only be used to secure interior doors. Grade 3 locks are easily “picked” open with a screwdriver or other tool.

Are Expensive Exterior Door Locks Worth the Price?

Cheaper door locks tend to erode more quickly than higher-end locks, especially when they are exposed to seasonal weather changes. Erosion of the cylinder tumbler causes the locking mechanism to malfunction, leading to key break-offs and other problems. In some cases, paying more for a high-quality door lock is recommended when the risk of experiencing an intrusion and/or robbery is high. Professional Locksmiths can help you decide which lock grade or lock type would best accommodate your needs.

Exterior Door Lock Glossary

Commonly used door lock and locksmithing terms include:


Cylinders consist of parts necessary for most locks to function properly, such as plug retainers, tumblers, plugs, and tailpieces.

Key Codes

Locksmiths can make keys according to a code number imprinted on a lock. Key codes prevent locksmiths from cutting off or replacing locks in most cases.


Keyways are grooves carved along the key blade. Keyways often have corresponding locks or can represent the groove configuration associated with a set of locks. A keyway capable of opening multiple locks is called a master key.

Chip Key

Chip keys incorporate computer chips that correspond to specific locks containing codes placed onto the chip. Transponder keys are a type of chip key.

Lock Rekeying By replacing tumblers comprising lock cylinders with tumblers of various measurements, a locksmith can rekey a lock so that a new key operates the lock. Rekeying locks eliminates the need to purchase and install new locks.


Inside some exterior door locks lies parts that have been precisely arranged to allow a specific keyway to manipulate them and open the lock. Combination locks have tumblers which align when the correct set of numbers are entered.

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