What Type of Locks Should Be Used on Exterior Doors?
Your exterior doors are the first barrier between your family, your belongings, and the outside world. The type of lock you put on those doors makes a real difference. A weak or outdated lock is easier to bypass than most homeowners realize, while the right lock adds a meaningful layer of protection.
This guide walks through the most common lock options for exterior doors, what makes each one suitable or not, and how to choose based on your specific situation.
Why the Right Lock Matters for Exterior Doors
Interior doors and exterior doors serve different purposes, and so do their locks. An interior lock only needs to offer basic privacy. An exterior lock needs to hold up against forced entry, weather, and wear over years of daily use.
Common entry points that burglars target include front doors, back doors, and garage entry doors — all exterior doors. Choosing the wrong lock type, or installing a quality lock incorrectly, can leave your home more vulnerable than you might expect.
1.Deadbolt Locks
Deadbolts are the most widely recommended lock type for exterior doors, and for good reason. Unlike spring bolts, which retract when pressure is applied, a deadbolt extends a solid metal bolt into the door frame and can only be moved with a key or thumb turn from the inside.
Single-cylinder deadbolts use a key on the outside and a thumb turn on the inside. This is the most common configuration for residential front and back doors.
Double-cylinder deadbolts require a key on both sides. While they add a layer of security — useful if there’s glass near the lock — they also create a safety concern during emergencies. Someone inside can’t exit without a key, which is a serious issue in a fire or other urgent situation. Check local fire codes before installing one.
Grade 1 deadbolts (the highest ANSI/BHMA grade) are worth the investment on any exterior door. They’re designed to withstand significantly more force than Grade 2 or 3 options.
When a deadbolt is installed, the strike plate matters just as much as the lock itself. A strike plate secured with short screws offers very little resistance. Use 3-inch screws that reach into the wall stud for real holding strength.
2. Knob Locks
Knob locks are common, but they are not designed for exterior use as a standalone security measure. The lock cylinder is located in the knob itself, which can be broken off with a wrench or hammer — a technique that takes seconds.
If you currently have a knob lock as the only lock on an exterior door, pairing it with a deadbolt is a straightforward upgrade. A locksmith in Fort Collins CO can install a deadbolt above the existing knob lock without replacing the hardware you already have.
3. Lever Handle Locks
Lever handle locks are easier to operate than knob locks, which makes them a good choice for accessibility reasons. However, they carry some of the same vulnerabilities as knob locks if used alone on an exterior door.
On commercial doors, lever handle locks are common — and they’re often paired with a deadbolt or an access control system to make up for the reduced security of the handle alone.
4. Smart Locks and Keypad Entry
Smart locks have become a practical option for both homes and businesses. They allow keyless entry via a code, smartphone, or both. Some models also integrate with home automation systems.
A few things to consider with smart locks on exterior doors:
Smart locks work well for homeowners who want to grant temporary access to guests, contractors, or housekeepers without cutting extra keys.
5. Mortise Locks
Mortise locks are set directly into the body of the door rather than mounted on the surface. This gives them a stronger fit and generally better resistance to forced entry compared to surface-mounted locks. They're common in older homes and on commercial doors.
The trade-off is that installation is more involved — a mortise pocket has to be cut into the door. Replacement and repair should be handled by a professional. If your home already has mortise locks, keeping them well-maintained is usually preferable to replacing them with standard deadbolts.
5. Rim Locks
Rim locks (sometimes called night latches) mount on the interior surface of the door and are operated with a key from outside. They're seen frequently in older homes and apartment buildings.
On their own, rim locks are not particularly strong. The mounting screws are exposed on the inside, and the bolt can sometimes be pushed back without the key if the mechanism isn't well-made. They work best as a secondary lock alongside a mortise or deadbolt.
What About Sliding and Patio Doors?
Sliding doors and patio doors need a different approach than traditional hinged doors. A standard lock is often not enough on its own.
Common additions to improve patio door security include secondary bar locks, pin locks through the frame, and door security bars that prevent the panel from sliding open even if the latch is bypassed. Some homeowners also install sensors that trigger an alarm if the door is opened or lifted.
If you're unsure whether your current setup is sufficient, getting a security assessment from a professional is worth the time. You can learn more about patio door security in Fort Collins to understand what options work best for sliding and French-style doors in this area.
How to Choose the Right Lock for Each Door
Not every exterior door needs the same level of protection. A few questions help narrow it down:
Is this a main entry point? Front doors, back doors, and garage entry doors are high-priority. Use a Grade 1 deadbolt at minimum, and consider a smart lock or secondary security measure for added control.
Is there glass near the lock? A double-cylinder deadbolt prevents someone from breaking the glass and turning a thumb turn to enter. Weigh that against the emergency egress risk mentioned earlier.
Is the door a sliding or French style? These need hardware designed specifically for their mechanism. Standard deadbolts don't apply.
Is this a rental property or business? Rekeying locks between tenants or employees is more cost-effective than replacing hardware. It also resets access so former occupants no longer have a working key.
Is the door frame itself strong? A high-quality deadbolt in a weak frame is limited in what it can do. Reinforcing the frame and using longer strike plate screws extends the effectiveness of whatever lock you choose.
When to Call a Locksmith
Installing a lock yourself is possible for some hardware, but a misaligned deadbolt or improperly fitted strike plate can reduce security significantly — even when the lock itself is high quality.
A licensed locksmith can assess your current setup, recommend appropriate hardware for each door, and handle installation correctly. If you've moved into a new home, changing the locks is one of the first things worth doing. You can't know how many copies of the old keys are out there.
Fort Collins Locksmith handles deadbolt installation, lock rekeying, smart lock setup, and security upgrades for both residential and commercial properties. Their team serves Fort Collins and the surrounding area, with same-day availability for most services.
Summary
For most exterior doors, a Grade 1 deadbolt is the foundation of solid door security. Knob and lever locks add convenience but should not stand alone. Smart locks are a legitimate upgrade when paired with a strong deadbolt mechanism. Mortise locks are worth maintaining on doors that already have them. Sliding and patio doors need dedicated hardware beyond a standard lock.
Getting the hardware right matters — and so does having it installed correctly. If you have questions about the locks on your exterior doors, reaching out to a locksmith in Fort Collins CO is a good starting point.
Fort Collins Locksmith | 1719 E Mulberry St Suite 7, Fort Collins, CO 80524 | (970) 478-2828 | fortcollinslocksmith.net
