When you are offered a "rate lock" from the lender, it means that you are guaranteed to get a set interest rate for a certain number of days while you work on your application process. This means your interest rate cannot go up during the application process.
Rate lock periods can be various lengths of time, anywhere from 15 to 60 days, with the longer period usually costing more. The 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 a shorter period.
In addition to opting for a shorter rate lock period, there are several ways you are able to score the best rate. The bigger the down payment, the lower the interest rate will be, since you will have more equity from the beginning. You can pay points to lower your rate over the loan term, meaning you pay more initially. For a lot of people, this is a good option..
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