When picking your exterior door locks, consider the lock’s grade and ease of installation.
Most lock manufactures have their products tested by the American National Standards Institute (ANSI) and Builders Hardware Manufacturers Association (BHMA) for grading on how their locks perform. They test based on operation, strength, cycle, security, material evaluation and finish.
Lock grade is the number of lock/unlock cycles you can expect your lock to complete before wearing out. It’s a reflection of the durability of the lock, not the amount of security it provides.
Locks that are Grade 1 offer the highest level of strength and security.
Before purchasing a lock, you must measure your door’s backset, cross bore and thickness to ensure you find the right fit.
Tip: Exterior doors are typically 1 ¾ inches thick, while interior doors measure 1 3/8 inches thick.
The "handing" of a door describes which way the door swings on its hinges, and thus whether you’d need a right- or left-handing handle or lock. The simplest way to determine the handing of your door is to stand in front of it and push it open. If the door swings in to you, walk to the other side of the door so you are on the exterior and can push it open to perform this test.
If the door hinges are on the left and it swings open to the left, you will need a left-handed handle for the exterior side and a right-handed handle of the interior side.
If the door hinges are on the right and it swings open to the right, you will need a right-handed handle on the exterior side and a left-handed handle on the interior side.
If you have a difficult time recalling the proper handing of your door, simply opt for a door lock labeled reversible handing, which means the lock can be installed on either side of the door.