You are considering purchasing a house in a new development that is currently being constructed. The price of the house is $400,000, and you are required to make a down payment of 20%. You have been approved for a 30-year mortgage with an interest rate of 3.5%. You plan to rent out the house for the first 5 years, after which you will move in and occupy the house. The current rent in the area is $1,500 per month, and you expect it to increase at a rate of 3% per year. If you sell the house after 20 years, what is the expected rate of return on your investment?