Single or double cylinder lock.

This is a choice homeowners need to make with the basic deadbolt lock. With a single cylinder lock, the deadbolt is opened by a key from the outside but is opened from the inside by a “switch” turn knob. Homeowners interested in additional security can go with the double cylinder deadbolt. This requires a key to both enter and exit the home. The benefit is that someone cannot reach in – perhaps from a nearby window or glass sidelights – and open a locked door from the inside.

A common problem with a double cylinder lock is a delay in exiting the home in an emergency or what if you lose the key in your home and are delayed. Many parents of teenagers use these locks to keep their kids from leaving the home without permission.