One of the easiest and most inexpensive ways to secure your home is to have the locks re-keyed. Many people think that in order to change the keys to their home it's necessary to change the locks. This is not the case. Re-pinning or re-keying the locks will accomplish the same task and is a very simple procedure. It involves changing the pins inside the lock so that the current keys will not open them but a new key provided by the locksmith will.
Reasons for re-keying can vary- the most important being the loss of your keys. Even if you have a spare set, it is possible that the person who finds your keys can trace them back to you. You should have your home rekeyed, if you have just moved in, whether you're renting or buying.
Even if you know the person you bought from quite well and feel comfortable that they either gave you all of the keys or have kept a duplicate for themselves, you'll never know who else had those keys in their possession long enough to have a copy made.
You may also choose to have the locks rekeyed so that they all operate on a single key. In order to do this, it's necessary to have all of the locks on the same keyway. (The keyway is the slot in the lock that the key fits into Usually different brands have different keyways so that the keys made for some locks won't fit into others. In some instances, such as Schlage or Corbin, it's possible to get several different keyways by the same manufacturer.)
Current day building codes recognize the importance of perimeter doors having a Deadlock mounted above a keyed doorknob or passage set. Key-in-knob locksets also referred to as Office or Entry Locksets offer minimum basic security from unwanted intruders. Having stated that fact, any lockset installed properly will perform to the level of security it was intended to provide. (Modern day key-in-knob locksets have a deadlocking feature in the latch, which is only operational in a properly aligned and installed situation.)
Deadlocking "Deadbolt" locks offer the most security in both residential and commercial installations.
The Deadbolt should have the equivalent of two ?" mounting bolts through a heavy mounting plate into an exterior lock body housing the cylinder in a slip-ring collar or crush-resistant casting on the exterior of the door.
The deadbolt itself should project 1" from the edge of the door and thence into the frame. Most deadbolts have a rolling pin in the bolt to prevent sawing it off. The strike plate on the frame should have the ability to take 3" screws projecting back into the stud framing beyond the doorframe material. (Not always possible where glass "sidelight" exist or masonry.)
The finished installation should operate as smoothly and the bolt should extend fully whether trying the lock with the door open or in its' closed position. (This will test the accuracy of the installation)
What's the cost?
Pricing is perhaps a very big concern at the time of purchase. As with key-in-knob locksets, the price of a deadbolt lock quite likely reflects the quality as well as the level of security.
Mass production has certainly brought down the price of locks. Unfortunately, it also can bring down the quality and performance.
Buy a name brand if possible. Consider the addition of "high security" deadbolts that generally add features like registered or restricted (read- "cannot duplicate") keys for custom keyways.
Features like restricted keys are not necessary if you do not loan out your keys or don't lose them or don't mind who may copy them or even order a key by the code. (Sorry, we had to mention that.)
A wide-angle door viewer will eliminate the need for a door chain, which offers little protection under force. Most installations of door chains rely on solid mounting to the door and frame that is not available in modern-day construction methods or materials. A door viewer allows you to decide whether to unlock you deadbolt after confirming your visitor.