Is the following co-ownership financing contract acceptable per Shariah?

I am buying a $100,000 house, and am $25,000 short. A 'friend' comes up with the $25,000. The house is purchased and registered in MY name. I sign another contract with my friend saying, he is 25% non-resident owner of the house, and I can buy him out. We both obtain the fair rental value of the house ($1000 per month). I buy him out at the end of 1 year by paying him $25000 + (12X250) = $28,000. i.e., his share plus 1 year's rent. Is my paying of $28,000 for his $25,000, which is totally based on the rental value, considered Interest? {If the house is registered in both the names, it gets quite complicated in terms of changing it later, and insurance and tax liabilities}