I don't see any advantage, except for building equity in the house quicker, since the rent will cover less of the mortgage/insurance/property tax payments. Is there something I'm missing? If the going rental rates would cover the entire M/I/PT in a 30 year, but might not in a 15 year, is there any reason to go with a 15 year? I mean, it's not like I would be paying that extra money on top of the house value (the interest). This would be for a duplex.