Having a duplex has many advantages compared to single family house. By having one, you will have someone who will be helping you pay the monthly mortgage. You can also decrease the value of the rental portion of your unit and have paper loss on your taxes. You will eventually be saving a lot of money for your taxes per year. Having a loan for a duplex is not that difficult and bankers prefer the duplex more than single family houses because they are certain you will be able to have help in paying up the monthly mortgage. With this, the payment rate for a duplex is usually lesser.