Acquisition and equity debt are defined here starting on page 9. <a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/p936.pdf">https://www.irs.gov/pub/irs-pdf/p936.pdf</a>
Note this is 2017 information. The changes for 2018 are that, instead of being able to deduct interest on home acquisition debt plus $100,000 of equity debt, you can only deduct interest on acquisition debt, not on equity debt. And for 2017, the overall mortgage deduction limit is $1 million, and starting in 2018, the overall deduction limit is lowered to $750,000 for new loans taken out after 1/1/18.
