A rate "lock" or "commitment" is a promise from the lender to freeze a certain interest rate and a certain number of points for you for a certain period of time during your application process. This saves you from working through your entire application process and learning at the end that your interest rate has risen higher.
Although there may be a choice of rate lock periods (from 15 to 60 days), the longer ones are usually more expensive. You can get a longer period for your lock, but in choosing this option, will most likely have a higher rate than you would with a shorter rate lock period
In addition to choosing a shorter lock period, there are other ways you can get the lowest rate. The larger the down payment, the smaller your rate will be, as you will have more equity from the start. You could choose to pay points to lower your rate over the life of the loan, meaning you pay more initially. To a lot of people, this makes sense and is a good deal..
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