When you're offered a "rate lock" from your lender, it means that you are guaranteed to get a set interest rate over a determined period while you work on the application process. This means your interest rate cannot get higher as you are going through the application process.
Rate lock periods can be various lengths of time, between 15 to 60 days, with the longer ones typically costing more. You can get a longer period for your lock, but in making this choice, will likely have a higher interest rate than you would with a shorter period
In addition to opting for the shorter lock period, there are several ways you are able to attain the lowest rate. A larger down payment will result in a lower interest rate, since you will have more equity from the beginning. You could choose to pay points to lower your interest rate over the loan term, meaning you pay more up front. One strategy that is a good option for many people is to pay points to bring the rate down over the term of the loan. You are paying more up front, but you'll come out ahead, especially if you don't refinance early.
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