When you're promised a "rate lock" from a lender, it means that you are guaranteed to keep a certain interest rate for a determined period while you work on the application process. This prevents you from going through your whole application process and discovering at the end that the interest rate has gotten higher.
Although there are various lengths of rate lock periods (from 15 to 60 days), the longer spans are usually more expensive. The lender will agree to freeze 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 that of a rate lock of a shorter period.
In addition to opting for the shorter rate lock period, there are several ways you can get the best rate. A bigger down payment will give you a lower interest rate, because you'll have a good amount of equity at the start. You might choose to pay points to reduce your interest rate over the loan term, meaning you pay more initially. For a lot of people, this makes sense and is a good deal..
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