How to Change Locks on Exterior Doors

Changing the locks on your outside doors is a smart way to protect your home, especially if you’ve just moved in. New locks for a new house ensure no one else has access, even if the previous owners handed over their keys.

You never know who might still have a copy: real estate agents, contractors, neighbors, or even pet sitters. Replacing your old locks gives you control and peace of mind.

The good news? You don’t need to be an expert to do it. With the right tools and some patience, most homeowners can install a front door lock replacement in under an hour.

This guide explains when to change locks in your house. It covers whether to rekey or replace locks. It also shows how to install or assemble a door lock step by step.

Why and When to Change Your Exterior Door Locks

Certain situations make it especially important to replace door locks:

• After moving into a new house
• If your keys are lost or stolen
• When locks are worn, rusted, or difficult to use
• If you're upgrading to smarter or more secure hardware

Even if nothing is wrong with your current locks, you might want to simplify access. Installing a lock system where all exterior doors use the same key is convenient and saves time. Many homeowners also take the opportunity to attach a lock to a door that previously didn’t have one — like a basement entry or garage access.

Rekeying vs. Replacing: Which Is Better?

Rekeying is a cost-effective alternative to full replacement. It involves changing the inner pins of your lock so a new key works with the old hardware. It’s ideal when the locks are still in good shape and you just want to limit access.

Rekeying is best when:

• The lock still works well
• You want to match multiple locks to one key
• You're looking for a cheaper solution without removing the whole unit

However, rekeying won’t help if the lock is damaged or outdated. If you want to improve your home’s appearance, security, or functionality (like switching to a keypad), then replacing is the way to go. For example, when dealing with older sliding patio doors or a rusted-out main door lock, replacing the unit will give you better performance and peace of mind.

What You’ll Need

To replace door locks, you'll need:

• Screwdriver (usually Phillips-head)
• Tape measure to check the door’s backset and thickness
• Pencil for marking holes
• Wood shims or a doorstop to hold the door steady
• Level for alignment
• Drill (optional, for new holes or tougher screws)

You'll also need a new lockset that includes a handle or knob, latch, deadbolt, and strike plates. If you're upgrading multiple doors, consider keyed-alike sets for convenience.

Whether you’re looking to replace a lock or install the door knob on a new entry, this toolkit will cover the basics.

Know Your Lockset: Key Components Explained

Before starting, it helps to understand the parts of your lockset. Most include:

• Knob or handle: What you grip to open the door
• Latch mechanism: The part that slides into the door frame
• Deadbolt: A more secure bolt that needs a key or thumb turn
• Strike plate: The metal plate on the door frame that the latch or bolt fits into
• Backplate and screws: Hold everything together

Higher-end locks may include anti-pick pins or reinforced plates for added security. Whether you’re installing basic hardware or a premium system, you’ll still need to carefully assemble a door lock to ensure smooth function.

Step-by-Step Guide: How to Change an Exterior Door Lock

1. Measure the Door and Existing Lock

Begin by measuring the door’s backset. This is the distance from the edge of the door to the center of the knob hole. Also, measure the door's thickness and the sizes of the holes. This ensures your new lockset fits correctly, especially on older doors.

2. Stabilize the Door

Use a shim or doorstop to keep the door from moving while you work. A steady door will make it easier to attach a lock to a door securely.

3. Remove the Old Handle and Latch

Unscrew the interior side of the handle. Once loose, pull off both the interior and exterior knobs. Then remove the latch mechanism from the edge of the door.

4. Remove the Deadbolt

Follow the same steps as above for the deadbolt. Unscrew the interior plate, remove both sides of the lock, and slide the bolt out of the door edge.

5. Install the New Lockset

Insert the new latch into the hole on the side of the door, with the angled side facing out. Then install the door knob or lever by aligning and securing both sides with screws. Make sure everything sits flush and operates smoothly.

Next, insert the deadbolt into the top hole and align the new lock pieces. Once secured, check the key operation before tightening completely.

6. Adjust or Install the Strike Plates

Replace the old strike plates on the frame with the new ones included in your lockset. Ensure they align properly with the latch and deadbolt. If not, mark and drill new pilot holes to reposition them.

Tips for a Smooth Installation

• Pre-drill holes in hardwood doors to prevent splitting.
• Test the lock before final tightening to make sure everything aligns.
• Keep old hardware labeled in case you need to refer to it later.
• Move slowly and double-check placement—rushing often leads to misalignment.

Whether you're replacing an old unit or installing hardware for the first time, assembling a door lock carefully ensures smooth use and long-term durability.

What If You’re Replacing the Entire Door?

Sometimes the problem goes beyond the lock. If your exterior door is cracked, warped, or drafty, it might be smarter to replace the whole door. Pre-hung doors, which come with a frame and lockset pre-installed, can save time and ensure better performance.

Feldco, a trusted name in home improvement, offers durable, energy-efficient exterior doors. Our products are designed for harsh Midwest climates, featuring mechanical interlocks and reinforced deadbolts for maximum protection. You can request a free online quote to get started.

Final Thoughts

Changing your door lock is a small job with big rewards. Whether you need new locks for a new house, are replacing damaged hardware, or simply want better peace of mind, this is a simple DIY upgrade with long-lasting benefits.

With just a few tools and a new lockset, you can install the door knob, replace the door lock, and secure your home in under an hour. And if you’re tackling a full door upgrade, Feldco’s solutions make the process seamless.

Once your new lock is in place, make extra keys, discard the old ones, and inform everyone who needs access. A secure home starts at the door, and now yours is ready.