"Rate Lock" and other Ways to Get a Lower Interest Rate
Lock It In
A rate "lock" or "commitment" is a promise from the lender to lock in a specific interest rate and a specific number of points for you for a certain period during your application process. This saves you from working through your whole application process and discovering at the end that your interest rate has gone up.
Although there are several lengths of rate lock periods (from 15 to 60 days), the extended spans are typically more expensive. A lending institution will agree to lock in an interest rate and points for a longer span of time, say 60 days, but in exchange, the rate (and sometimes points) will be more than with a rate lock of fewer days.
More Ways to Save on Interest
In addition to going with the shorter lock period, there are other ways you are able to attain the best rate. The more the down payment, the lower your rate will be, since you will have more equity from the beginning. You can pay points to lower your interest rate over the term of the loan, meaning you pay more up front. One strategy that makes financial sense for many people is to pay points to bring the rate down over the life of the loan. You pay more initially, but you'll save money in the long run.