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What is a double cylinder deadbolt?

Silver Double sided deadbolt lock and keys

We’re all familiar with the standard single cylinder deadbolt that every front door has, but what is a double cylinder deadbolt?

A double cylinder deadbolt is a deadbolt lock that requires a key from the outside as well as the inside of the door. Here are a few reasons why people choose to use this specific lock versus the standard single cylinder deadbolt.

The benefits of a double cylinder deadbolt

Although most people are familiar with the single cylinder deadbolt, where you have the thumb turn on the inside. There are times where having a double cylinder deadbolt would make more sense. The first reason why you may need a double cylinder deadbolt is if you have a door that is fully or mostly glass or when there is glass on the sides of the door. In this case if you have a single sided deadbolt it becomes very easy to break into the property. All the burglar has to do is break the glass, reach inside and turn the thumb turn to unlock the deadbolt. To prevent this problem you would get a double cylinder deadbolt which would have a key on both outside and inside. If a burglar breaks the glass on the door he would still not be able to enter, since he will need a key to unlock the deadbolt.

Second reason you would need a double cylinder deadbolt if you have a young child or a dog who are clever and tall enough to reach the thumb turn and unlock the door, you wouldn’t want them to be able to open the door and be outside unattended. Maybe you have an elderly parent who lives with you who has Alzheimer's you’ll want to prevent them from unlocking the door and wonder off to the street and get lost.

Once you decide that a double cylinder deadbolt is the right fit for you, you’ll want to make sure you remove the key from the deadbolt after locking the door. This will solve any issues of anyone who is not supposed to unlock the door from doing so.

If you have similar doors with glass on or around them or need to prevent someone from unlocking the door call Locksmithland for a free estimate, we’re located in Delray Beach and provide services in all of Palm Beach County. 📞 (561) 295-1818

a burglar breaking a double cylinder deadbolt

Cautionary measures that must be taken while using the double cylinder deadbolt

Although this lock gives you extra control and security, in order to not defeat the purpose you would need to place the key somewhere close to the door but not in a visible place in case a child or burglar could easily reach. Also in case of a fire if this is the only door you can use to exit your home you don’t want to be trapped inside of the house because you’ve misplaced the key, so make sure you always put it at the same spot. One option is mounting a key as close to the door as you possibly can but keep in mind that if someone breaks the window from the outside they won’t be able to see or reach it.

A double cylinder deadbolt


The double cylinder deadbolt is a very good lock for homes that are exposed with glass on or around the door and when trying to prevent family members from wondering off. Cautionary measures must be taken while using this hardware in cases of fire or other emergency situations.


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