Types of Locks
Dead bolts. Dead bolts are the most popular type of residential lock because they are not too costly but still offer superior protection. This type of lock prevents intruders from opening the door using a credit card. Dead bolts come in single- or double-cylinder designs. Single-cylinder dead bolts are locked by a key only from the outside, while double-cylinder designs can be locked with a key from the inside and outside. Using a key to lock from the inside and outside can provide a higher level of protection, but it is important to note that having to unlock the door with a key from the inside will make it harder to leave your house quickly during an emergency.
Knob and lever-handled locks. Mostly used on interior doors, the locking cylinder in knob and lever-handled locks is located within the handle, which means they provide lower protection because the door can be opened if the handle is removed or broken. Because these types of locks can be forced open, they are typically not suitable for exterior doors or other high-security areas unless they are combined with other security measures.
Keyless entry pads. Usually opened with a security code or by sensor that reads a card, keyless entry pads are most popular at hotels and offices because they can easily be reset if a card is stolen or misplaced. Computerized locks, which save records of entry, are also very easy to monitor.