A rate "lock" or "commitment" is a lender's promise to hold a specific interest rate and a specific number of points for you for a specified period of time during your application process. This saves you from working through your entire application process and learning at the end that the interest rate has risen higher.
While there are several lengths of rate lock periods (from 15 to 60 days), the longer spans are usually more expensive. You can get a longer period for your lock, but in making this choice, will likely have a higher rate than you would have with a shorter rate lock span of time
There are more ways to get a lower rate, besides opting for a shorter rate lock period. A bigger down payment will result in a reduced interest rate, since you'll be starting out with more equity. You can pay points to bring down your interest rate over the term of the loan, meaning you pay more initially. To many people, this is a good option..
Do you have a question regarding a mortgage program?