What if I refinanced?
When you refinance a mortgage that was treated as acquisition debt, the balance of the new mortgage is also treated as acquisition debt up to the balance of the old mortgage. The excess over the old mortgage balance is treated as home equity debt. Interest on up to $100,000 of that excess debt may be deductible under the rules for home equity debt. Also, you can deduct the points you pay to get the new loan over the life of the loan, assuming all of the new loan balance qualifies as either acquisition debt or home equity debt of up to $100,000.
That means you can deduct 1/30th of the points each year if it’s a 30-year mortgage—that’s $33 a year for each $1,000 of points you paid. In the year you pay off the loan—because you sell the house or refinance again—you get to deduct all the points not yet deducted, unless you refinance with the same lender. In that case, you add the points paid on the latest deal to the leftovers from the previous refinancing and deduct the expense on a pro-rated basis over the life of the new loan.