The number of products available has also risen in the past year, from 74 in February 2020 to 109 today. Eleanor Williams, financial expert at Moneyfacts, says: 'These positive shifts in both the number of lenders and Rio deals are great news for older borrowers.' Why are these products becoming more popular, and when should you consider getting one? How does a Rio mortgage work? Rios are similar to normal interest-only mortgages, in that you agree only to pay off the interest each month for the term of the mortgage, and then pay the rest of what you owe when that period comes to an end.