While most people are already familiar with the standard door lock types, several more options are helpful in different situations. Here’s what you should know about them, including the pros and cons of each.
Disclaimer: The information included in this post is for informational purposes only and should not be taken as legal, financial, or DIY advice. We highly suggest consulting a professional before attempting any DIY home improvements or repairs.
7 Common Door Lock Types
The 7 most common lock types, and the ones we’ll be discussing here include:
- Barrel Bolts
- Chain Locks
- Electronic Locks
- Knob Locks
- Mortise Locks
- Vault Locks
Lock Design Theory
All locks ultimately follow a simple design choice: they have to decide whether to be one-way or two-way. Everything else is just a matter of details and complexity.
One-way locks can only lock or unlock from one side. These include options like barrel bolts and some types of vault locks. Chain locks are theoretically one-way.
But depending on the design it’s possible to unlock them from the outside, so they don’t quite fit into this category. One-way locks are secure for anyone on the locking side, but they can be problematic in emergencies.
So they’re also a little more dangerous than other lock types. Most one-way designs are nearly impossible to lock from the outside, too, so it’s difficult to lock yourself out of something accidentally.
Two-way locks can open and close from either side. Most locks fall into this category, although they rarely have the same security level on both sides. A traditional deadbolt with a knob on one side and a keyhole on the other is a two-way lock.
Two-way locks are much more user-friendly, but ultimately not quite as secure as one-way locks. Finally, remember that people can bypass any lock with enough time.
There’s no such thing as a perfect lock, and even thousand-pound safes and vault doors are breakable. However, a sufficiently sturdy lock will deter casual entrance and often keep intruders out long enough for other security systems to work.
The Main Types Of Door Locks
Here are the main types of door locks available:
1. Barrel Bolts
Barrel bolts are simple locks consisting of a cylinder of sturdy material, usually metal, that you can rotate and slide back and forth. These are one-way manual locks that provide strong protection from one side while also being easy to use.
Barrel bolts generally rely on the strength of the screws holding them into the frame to resist impacts and attempts to break through them.
This means they work better in places with solid frames, but putting them in areas with weak or breakable frames makes them much less durable. To counter this, some people install several barrel bolts at different heights.
This distributes the locking force and significantly increases the difficulty of breaking through them. It’s much easier to get through a barrel bolt if the other side exposes any part of it, which runs the risk of cutting things.
Ideally, intruders won’t be able to see them. Overall, barrel bolts are highly effective against casual theft because they’re difficult for regular thieves to get through. However, they won’t last long against a destructive or well-prepared thief.
Firefighters encounter barrel bolts regularly, for example, and they can usually bypass these within a few seconds because they don’t need to care about noise or damage.
2. Chain Locks
Chain locks are the weakest option on this list because they’re easy to bypass if you know how. They’re arguably too weak to work as security on their own, which is why hotels and other places that use them often add barrel bolts or other types of locks to supplement them.
Chain locks use a simple design where a chain several inches long attaches to a knob that can slide into a secure fixture on the backside of the door.
This allows a door to open up to a few inches and stops people from simply shoving the door open, but doesn’t keep the door completely locked. Chain locks are generally appropriate when someone wants to open a door to talk but stop someone from entering the room.
Although easy to bypass, either by the method linked above or with metal-cutting tools, a chain lock will still take someone at least a few moments to get through. That gives someone enough time to run away or at least call for help.
Deadbolts are among the most popular options for securing homes. They come in several configurations, including locking from one or both sides, and mainly feature a springless piece of metal that goes between the door and the frame.
The bolt part is thick enough that it’s challenging to cut or break with force, so most people don’t bother trying that unless there’s no other option.
Modern deadbolt systems may also have additional features, including protection from drills and such that make it hard to damage and unlock them without destroying them. However, like all keyed systems, a sufficiently capable individual can pick them off.
A poor lock is pickable in seconds, while a high-quality option may require as much as 15 minutes to get through. This is too long for many burglars, who will often give up rather than persist in trying to get through such a lock.
Finally, deadbolts are only lockable with a key from the outside. Such a design means you can’t accidentally lock yourself out of a home or business that only has a deadbolt for security.
4. Electronic Locks
Electronic locks are the modern option. These are particularly popular in hotels and some businesses, and most have a manual option for unlocking things if the electronic system fails.
Electronic security systems offer some advantages over traditional locks, including the ability to control who can get through each door.
Using electronic locks is cheaper and easier than stationing a security guard at every entrance to check someone’s credentials. Most electronic locks are also hard to pick with traditional tools, which provides an additional advantage over manual locks.
However, they lose most of their functions if they’re cut off from an electricity supply. Most electronic locks will also wear out, which makes them a poor choice for long-term security.
In short, electronic locks have many advantages, especially in environments where it’s easy to replace them when there’s a problem. However, they’re much riskier when they’re the only option.
5. Knob Locks
Knob locks are the single most popular option in most homes. These hold within doorknobs and usually have a lock on one side and a keyhole on the other.
Knob locks for interior areas may not have a keyhole but are easy to unlock just by turning a small groove on the outside. Indoor knob locks are more for privacy than security. While relatively easy for a professional to pick and bypass, knob locks are cheap and will deter most casual intrusions.
That’s all the security most people want, especially for areas that aren’t too important. For home security, people usually pair a knob lock with a deadbolt.
Having two locks makes the entire system much harder to bypass, although it also introduces another point of failure if the lock or key breaks. People who only use one lock for a door usually go for a deadbolt because it’s more secure overall.
6. Mortise Locks
Mortise locks are rare in homes but common in businesses. They work well for high-traffic areas and come in many designs, including day/night controls to make it harder to unlock at certain times. Mortise locks are pickable.
But it’s harder to get through them than most other locks, which is one of the main reasons businesses favor them. It’s usually easier to drill into them if they’re causing trouble.
High-quality mortise locks usually have at least five bolts that go into a door frame, each of which someone needs to pick to get through. Mortise locks are durable but may require care to service or replace.
7. Vault Locks
Vault locks are almost always interior locks, rather than something exposed to the elements. Although most often associated with banks and casinos that need to store a lot of valuables, it’s possible to install a vault lock on almost any door.
Some people use these to create safe rooms or bunkers within their homes. The main difference between a vault lock and other types of locks is that a proper vault usually has several steps that you have to go through to unlock it.
Keys are often just one part of the process, so a vault will thwart any casual attempt to bypass it. However, it’s still possible to get through these locks if you have a drill and enough time.
The main disadvantages of vault locks are the time it takes to open them and the fact that they’re usually obvious, so people know there’s something important behind them.
A sneakier option is using a vault lock as a nonfunctional gimmick where it sounds like it works, but never unlocks anything. For this setup, a hidden keyhole is the real way to unlock things.
Frequently Asked Questions
Here are some common questions people have about door lock types.
What is the best lock for a main door?
Most homeowners prefer deadbolts as the main lock. Businesses usually prefer mortise locks, which can stand up to significantly heavier use.
Which door lock is the safest?
Vault lock systems are the safest because they take the most time to get through. However, they’re also more secure than people usually need. Mortise locks and deadbolts are safer for regular main doors, while barrel bolts and electronic locks are for elsewhere uses.
Which door locks are best for homes?
The best external door locks are a deadbolt and, optionally, a knob lock. The best internal door locks are knob locks, although most people add a deadbolt to their garage door if it’s directly connected to the house.
Electronic locks are popular alternatives in some higher-class neighborhoods, but not as reliable unless you have a manual alternative and an uninterruptible power supply.
What is a Grade 1 Lock?
A Grade 1 lock is a lock that complies with ANSI standards. Grade 1 is the highest and means the lock can withstand multiple blows, while Grade 3 is the weakest.
How expensive are door locks?
Door locks range from about $15 to $50 for a typical option. Higher-quality options, like good deadbolts, can cost up to $200 in most areas. Chain locks and barrel bolts tend to be on the cheapest side.
Mortise and vault locks vary based on complexity. Some mortise locks cost as little as $10, but a genuinely good option will probably run above $300. Vault doors are usually several thousand dollars, minimum.
Getting the Right Lock for The Job
As you can see from the list above, there are many door lock types and they vary in details like price, security, and how you can unlock or defeat them.
It’s always better to get the right fit for your security needs. If you aren’t sure which lock makes sense, talk to an installer.