You'll need to look at your 2017 tax return.
If the home mortgage interest was used as a deduction on your 2017 return (Schedule A) you need to reort the refunded interest as income on your 2018 tax.
- Select Federal Taxes
- Wages & Income
- Scroll to Less Common Income
- Select Miscellaneous Income (last item), start
- Then select Reimbursed deductions from a prior year
"It is a refund (or credit) for overpayment(s) of interest you made in a prior year or years. If you itemized deductions in the year(s) you paid the interest, you may have to include part or all of the box 4 amount on the “Other income” line of your 2019 Schedule 1 (Form 1040). No adjustment to your prior year(s) tax return(s) is necessary. For more information, see Pub. 936 and Itemized Deduction Recoveries in Pub. 525."
