A rate "lock" or "commitment" is a lender's promise to freeze a particular 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 entire application process and discovering at the end that the interest rate has gotten higher.
Although there may be a choice of rate lock periods (from 15 to 60 days), the longer ones are typically more expensive. You can get a longer period for your lock, but in making this choice, will probably have a higher rate than you would have with a shorter span of time
In addition to going with a shorter rate lock period, there are several ways you can attain the lowest rate. The larger down payment you can make, the smaller the rate will be, as you will have more equity from the beginning. You could choose to pay points to reduce your rate for the loan term, meaning you pay more initially. One strategy that is a good option for some is to pay points to bring the rate down over the life of the loan. You pay more up front, but you'll come out ahead, especially if you keep the loan for the full term.
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