Have I claimed things twice and received a bigger return?

[kirsten-wiley]

I only own one house, and I live it in full time (all year).  I set-up a room to begin renting in November (didn't get a tenant until December).  When entering information for renting out the room, it describes how it's still rental property, just a "portion of a single property."  

I entered my 1098 information on the Deductions and Credits (entering my Mortgage interest, real estate taxes, mortgage insurance premiums, etc.); THEN, it also requested this SAME information for the rental property.  After I entered it for the rental property, my estimated federal refund skyrocketed (doubled!).  I feel like I may have entered this incorrectly because I didn't expect this to happen, especially since I only received income for the room for  less than one month (28 days) and a security deposit (roommate still living with me).

[MichaelMc · Accepted solution]

You were right to question the result that you observed. This happens frequently and is easy to correct.

Go back to the Deductions and Credits section of your tax return and delete your entries for mortgage interest, PMI, and real estate taxes.

Go to the Wages and Income section, scroll down to Rental Properties and Royalties. In this section, please review your entries for common expenses, being certain that you entered the total for the year.

TurboTax will apportion your common expenses based on the rental space and the period of time in use as a rental. The remainder of those expenses will be transferred to Schedule A as potential itemized deductions.