A rate "lock" or "commitment" is a promise from the lender to freeze a specific interest rate and a particular number of points for you for a certain period of time while your application is processed. This saves you from working through your entire application process and learning at the end that your interest rate has gotten higher.
Rate lock periods can be various lengths of time, between fifteen to sixty days, with the longer period generally costing more. The lender can agree to lock in an interest rate and points for a longer span of time, such as sixty days, but in exchange, the rate (and sometimes points) will be more than with a rate lock of fewer days.
In addition to going with a shorter rate lock period, there are several ways you can score the best rate. A bigger down payment will get you a lower interest rate, because you'll have more equity from the beginning. You can pay points to improve your interest rate over the loan term, meaning you pay more initially. To many people, this makes sense and is a good deal..
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