Under this arrangement, the borrower pays interest on an annual basis to the lender and makes a balloon payment of principal at the end of the payment term. A balloon mortgage allows you to enjoy low monthly payments for several years — with a big catch.A balloon mortgage is usually rather short, with a term of five to seven years, but the payment is based on a term of 30 years. Following that default, the plaintiff accelerated payment. A balloon mortgage is a loan with low initial payments, but it requires the borrower to repay the balance in full in a lump sum. There will be no prepayment penalty.