Locks, Deadbolts and Keypad Locks

Key, keypad or smart lock: how the door should open

A mechanical deadbolt is the simplest and needs no power. Keypad locks add a code, biometric ones read a fingerprint, and smart locks work from a phone or card reader, but most electronic locks rely on batteries. Check that the lock has a backup, such as a key cylinder or contacts for an emergency battery, and remember that an override cap or cover can be model-specific. The category also holds queue barriers, card readers and key-control accessories, which are chosen by the system they connect to rather than by the door.

Backset, bore and grade: whether it fits your door

Before choosing, measure the door. Backset, the distance from the door edge to the center of the hole, is usually 2-3/8 or 2-3/4 inches. The cross bore is commonly 2-1/8 inches and the edge bore 1 inch, and doors are most often between 1-3/8 and 1-3/4 inches thick. Many electronic locks reuse the existing holes, but the strike plate and bolt must still line up with the frame. Replacement parts and covers listed by model number fit only that model.

Questions about Locks, Deadbolts and Keypad Locks

What happens if the batteries die in a keypad lock?

Many electronic deadbolts keep a key cylinder or two external contacts where a 9 V battery restores power long enough to enter the code. The listing should say which backup is present. Replace the cells at the first low-battery warning rather than waiting for the lock to stop responding.

Single-cylinder or double-cylinder deadbolt?

A single-cylinder deadbolt uses a key outside and a thumb-turn inside, so anyone can leave quickly in an emergency. A double-cylinder one needs a key on both sides, which resists a break-in through nearby glass but can trap occupants, and some local codes restrict it. Check the rules that apply to your building.

What do lock grades mean?

ANSI/BHMA Grade 1 is the highest, tested for commercial use with the most cycles and force. Grade 2 suits light commercial or demanding homes, and Grade 3 is basic residential. A lock is only graded if its listing says so, so do not assume a grade from how solid it looks.