
Discover the average deadbolt installation cost, price factors, and tips to save on your project. Learn how to budget for secure home upgrades.
While many choose double-cylinder locks for security, this option comes with risks
Double-cylinder keyed deadbolt locks require a key on both sides of your door, offering stronger security than single-cylinder locks with interior knobs.
Double-cylinder deadbolt locks cost $40 to $80 for materials, making them an affordable security upgrade when you install them on exterior doors.
Your double-cylinder lock creates emergency exit risks since you need a key to unlock the door from inside during fires or urgent evacuations.
Hiring a local locksmith professional ensures your deadbolt installation meets local fire codes and operates smoothly, preventing lock malfunctions that could trap you inside.
Homeowners commonly install double-keyed (double-cylinder) deadbolt locks as security features on exterior doors. However, if you’re considering installing one, you need to do your research concerning double-cylinder deadbolt safety. Make sure this lock upgrade is right for you by learning all the risks—and rewards—of double-keyed deadbolt locks.
The most common type of deadbolt, the single-keyed deadbolt, only requires a key for entry from the outside. The inside of the deadbolt features a knob that locks and unlocks the door.
A double-cylinder deadbolt has key-entry locks on both sides. That means someone inside a house with a double-keyed deadbolt lock is staring at a keyhole in the spot where a person with a single-key deadbolt would see a knob. You’ll need a key to lock and unlock the door from the interior and exterior.
The cost to install a double-keyed deadbolt isn't necessarily more expensive than a single-keyed deadbolt because the installation process is essentially the same.

Security is the main reason why some people opt for double-sided deadbolts. Technically, with a single-keyed deadbolt, a persistent intruder could break a glass window to reach inside to unlock the deadbolt using the knob with a simple twist of the thumb-turn. This situation can’t happen with a double-sided deadbolt if the key isn't in the interior key slot.
Many caregivers may also opt for double-sided deadbolts as an added security measure because no one is able to leave through that door without a key once the deadbolt is locked. This type of deadbolt may even offer an additional deterrence for would-be intruders since picking a lock takes longer and can add complexity to the entry. A double-cylinder deadbolt not only offers an additional layer of security, but it’s cost-effective, too. The average cost of a double-cylinder deadbolt is $40 to $80, and you can install them on your own or hire a professional locksmith.
The same features that make double-keyed deadbolts attractive to people seeking added security can make them dangerous in emergencies. Here's a rundown of what to know:
The interior side requires a key to open the door when it is locked
Must locate key when evacuating in fires and other emergencies
Risk of being trapped in your home if the key is lost
Risk of being trapped in your home if the lock jams or breaks
Easier to get locked out of your home
Double-cylinder deadbolt locks are not considered safe for emergency exits. Some safety experts don't believe they belong in residential homes at all. In fact, double-keyed deadbolts are actually illegal in some places. This can vary by your:
City
State
Dwelling type
In some dwellings, fire code dictates that double-keyed deadbolts cannot be used on egress doors. It's especially important to consider the liability of using double-keyed deadbolts in rental properties. Be sure to check local regulations before installing such a lock.
First, confirm what type of lock you're legally allowed to add to your home by looking at local and state laws. While there is no federal law prohibiting deadbolts requiring two keys, you could violate local codes if you upgrade to a double-keyed deadbolt on even just one door in your home.
If you have a unique situation where you feel that a double-sided deadbolt is the safest option available, consider bringing in a certified local locksmith or door installer to oversee the deadbolt installation. The cost to change locks may be worth it for you to ensure proper installation.
When installing a deadbolt that may increase the risk of being trapped in your home during an emergency, you want to make sure that everything is installed based on code requirements and manufacturer standards to prevent any malfunctions that could cause the lock to stick. If you install this or any lock, be sure to talk with everyone in your home about how to operate it in case of an emergency.
Great job! Friendly, timely and thorough.
I call them all the time when i need locksmith services. They did my car key, business lock changes, safe opening. Pretty good with what they do. Reasonable prices
Jason has helped me with multiple household projects, with the most recent being new door installation. He has always showed up on time and organized and has done an incredible job! Jason is very professional and he's now my go-to for anything around my house that needs to be fixed or...
Professional and great to work with. Reliable, detail-oriented and knowledgeable. Will hire again in the future!
Custom Paint Jobs LLC made our dream kitchen a reality with their expert painting.
I only want to hire them!!
Great job...edging and pre clean up went well with a great job with seal coat. Friendly, efficient and professional.
Called ahead and worked quickly to install keyless locks on vintage wooden doors.
I contacted Greg through the Angie's List message center. He replied through the message center and called the next morning to schedule the service call. He arrived promptly. He rekeyed the front and back door locks. He was done in under a half hour. Even my dog liked him. I couldn't have...
Called on Friday, was able to get appointment on Monday morning. Service rep requested a reminder call from me to make sure that he was awake and that he could make it in Monday morning. I agree that none of us like Mondays, but that seemed a little lazy and since I needed help, I was happy...
From average costs to expert advice, get all the answers you need to get your job done.

Discover the average deadbolt installation cost, price factors, and tips to save on your project. Learn how to budget for secure home upgrades.

Both single and double cylinder deadbolts will enhance your home’s security. Learn all about double versus single cylinder deadbolts to find out which is right for you.

Compare a double-cylinder vs. a single-cylinder deadbolt lock to determine which is better for your home doors.

Learn about different types of deadbolts on the market and which one will make your home the most secure.

Deadbolts can protect your home, family, and belongings from unwanted guests if installed correctly. Read this guide to learn more about choosing and installing the right deadbolt for your home.

Which is better for protecting your home—smart locks or traditional locks? Use this guide to weigh their differences and decide which is better for you.