If the money was used to improve your primary home and the primary home secures that loan, then on the 1098 either box 7 is checked, or the address of the property that secures the loan is shown in box 8. In that case, it's a SCH A itemized deduction and gets entered in the same place your enter your primary loan mortgage interest. That would be under the Deductions & Credits tab in the "Your Home" section where it asks for mortgage interest.
