How can I tell if my door lock is secure?

1. Buy the best lock you can afford. Insurance company research shows that burglars often bypass homes with high-quality locks because they’re harder to pick or break.

2. Insist on a lock that has an ANSI Grade 1 classification. That means it has a high rating from the American National Standards Institute (ANSI) for durability and performance.

3. Buy a deadbolt with an inch-long (or longer) horizontal bolt.

4. Choose a lock that comes with a one-eighth-inch thick (or thicker) reinforced strike plate (it’s the metal piece that the lock’s bolt slides into). Every door lock comes with a strike plate, but many of them are cosmetic and don’t provide much security. In fact, the strike plate’s attachment to the door frame is usually the weakest part of the door. Insist on a heavy-gauge metal reinforcing strike plate. Mount it with three-inch-long screws that secure it to the wall framing, not just to the door frame jamb.

5. For even more security, consider buying a lock with these special features:

• Anti-Drill Feature. Hardened steel chips within the lock housing tear up a drill bit when someone tries to drill through the lock.
• Saw-Resistant Bolts. Internal anti-saw pins spin freely inside the bolt to spin back and forth with every movement of a saw blade—which will foil someone’s effort to saw through the lock.
• Hardened cased steel or beveled casings. The outside housing of a deadbolt lock is called the "casing" or "case." Some are made from hardened steel, which makes the casing more resilient against blows from a hammer. Some casings are beveled, which makes it hard to get pliers or pipe wrenches to stay on the lock while trying to twist it loose.
• Double-cylinder deadbolt. A lock that opens only with a key from the inside or outside is a good choice if you choose a door with glass sidelights or panels. A burglar can break the glass and unlock the door if it’s not keyed from the inside. (Check your local building codes and with your insurance to make sure double-cylinder deadbolts are allowed in your area. In some places, the locks are considered a fire safety issue.)

6. Keep track of the people who have copies of your house keys. Sometimes thieves get keys from an acquaintance. Some manufacturers offer locks with keys that can be copied only by certain locksmiths or by the manufacturer.

7. Pay as much attention to securing the door to your attached garage as you do to the front door.