Borrowing against an owned home is not an option unless the money is used directly for that home. Home mortgage interest deduction is restricted to interest paid on mortgage debt used to purchase or improve a residence, or to refinance the remaining balance on a purchase or improvement.
The purchase of an RV, therefore, does not qualify for this deduction. Home equity loans limit the amount of interest that is deductible, if your RV loan balance exceeds $100,000. Home mortgage interest deduction is limited to interest paid on home equity loans up to $100,000.