Using Potential Rental Income for Purchasing a Duplex

[Tim C.]

Hi everyone, 

Pretty much every blog or every podcast I listen to here mentions that you should "house hack" and "live in one side and rent out the other." In detailing the advantages of doing this they go on to say that you can count the potential earnings of the duplex's side you are not living in to help you qualify for the loan. 
Ex: https://www.biggerpockets.com/renewsblog/becoming-a-landlord-the-easy-way/

Every lender in my state of IL has said that their rules for Fannie Mae do not allow you to count potential earnings on the rental to qualify. Instead they will allow you to use the rental after a year to refi the loan. 

Has anyone ran into this? The duplex I was trying to purchase was vacant so that's why it didn't work. Had they counted the income from the rental, I would have qualified for the deal. How am I supposed to purchase this home when I need to own the home to lease it and qualify for the loan?