A rate "lock" or "commitment" is a promise from the lender to hold a certain interest rate and a specific number of points for you for a specified period during your application process. This protects you from working through your whole application process and learning at the end that the interest rate has risen higher.
Rate lock periods can be various lengths of time, between fifteen to sixty days, with the longer ones generally costing more. You can get a longer period for your lock, but in making this choice, will most likely have a higher interest rate than you would have with a shorter rate lock period
There are more ways to get a better rate, in addition to agreeing to a shorter rate lock period. The bigger down payment you make, the smaller the interest rate will be, because you will be starting with more equity. You can pay points to lower your interest rate over the life of the loan, meaning you pay more up front. To many people, this makes sense and is a good deal..
Do you have a question regarding a mortgage program?