how does this work can someone explain?

I have been house hunting for 2 months now, and have yet to find something I like that is in the price range. yesterday I spoke with a gentleman who is renting a house but said he would do rent to own with us. I explained to him we could get financed for a house but we dont have a large sum to put down or to cover closing costs. He said we could rent the house for a year and finace it as a refinance. can someone explain. He said our rent money would show equity in the house.