Problem
You are buying a house and will borrow $205,000 on a 30-year fixed rate mortgage with monthly payments to finance the purchase. Your loan officer has offered you a mortgage with an APR of 4.35%. Alternatively, she tells you that you can "buy down" the interest rate to 4.15% if you pay points up front on the loan. A point on a loan is 1% (one percentage point) of the loan value. How many points, at most, would you be willing to pay to buy down the interest rate?