Dead Bolt KnobThe most popular kind of deadbolt, the single-keyed deadbolt, only needs a key to be turned in order to gain access from the outside. A knob that locks and unlocks the door is found on the interior side of the door. Both sides of a double-cylinder deadbolt have key-entry locks. In a home with a double-keyed deadbolt lock, a person inside is seeing a keyhole where a knob would be seen by a person with a single-key deadbolt. To lock and open the door from the inside and outside, you’ll need a key.

People install double-sided deadbolts primarily for security reasons. With a single-keyed deadbolt, for instance, a determined burglar could smash a window to reach inside and use the knob to unlock the deadbolt. If the key is not in the interior key slot, this scenario cannot occur with a double-sided lock.

Another use for these locks is in situations where the home is occupied by an elderly person who needs supervision. Because no one can exit through that door without a key after the deadbolt is secured, many caretakers use double-sided deadbolts as an additional security feature.

Double Keyed Dead BoltUnfortunately, the same safety features that make a double-keyed deadbolt attractive can be a nuisance in some scenarios and a safety hazard in some situations. These deadbolts can be a nuisance if the door is locked and the key is misplaced. You now have to find the key before you can leave the house. Now if there is an emergency, this nuisance can become a threat to life and limb. If a primary egress door is locked and there is a fire in the home, occupants of the home can become trapped. If someone is injured and needs to be taken to the hospital, a locked door with a misplaced key can cost precious time. If an intruder is in the home, a double-keyed lock can trap the home’s occupants in the home with the intruder.

Fire codes in some homes prohibit the use of double-keyed deadbolts on egress doors. In rental houses, it’s crucial to take into account the liability of using double-keyed deadbolts. Before installing such a lock, be sure to check local laws. There are many possible scenarios where quick egress of the home is needed and a double-sided lock could prevent it. For this reason we recommend replacing any double-sided locks in the home with single-keyed deadbolts.

Thankfully, replacing a lock in most situations is a straight-forward process that can be done by the homeowner. You can find information about how to replace a lock in this video:

https://www.youtube.com/watch?v=dY68HwCwviA&t=94s