When you are offered a "rate lock" from the lender, it means that you are guaranteed to keep a set interest rate for a certain number of days for the application process. This ensures that your interest rate will not go up during the application process.
Rate lock periods can vary in length, anywhere from 15 to 60 days, with the longer period generally costing more. A lender can agree to hold an interest rate and points for a longer span of time, say 60 days, but in exchange, the rate (and sometimes points) will be higher than that of a rate lock of fewer days.
There are other ways to get a reduced rate, besides going with a shorter rate lock period. The more the down payment, the better the rate will be, as you will have more equity from the beginning. You may opt to pay points to improve your rate over the loan term, meaning you pay more initially. To a lot of people, this makes sense and is a good deal..
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