Seems like there are a lot of little issues with this spreadsheet. Some in your favor, some not.
First off, your including part of your state tax as part of your tax benefit of homeownership even though you’d receive that even if you didn’t have home related deductions (7000 > 5500, you’d get 25% of 1500 as tax benefit regardless). If you don’t believe me, zap rows 23 and 24 and you’ll see.
When you say you’re in the 25% bracket, are you combining fed and state? If so, that seems a little low (so your tax benefit would be higher), but I really only know my own tax bracket and it sucks. The tricky thing with brackets is you can’t always treat your first dollar like your last. Some of your basis may fall in a different bracket, so you should at least consider that.
Not sure how you arrived at a property tax basis of less than 1%. Is this in San Diego?
Also, on the last comment, I don’t really know any of the tax implications of renting out part of your home, but isn’t the answer somewhere in the middle? That is, I can claim some of the interest and some of the depreciation? For normal rentals, can I deduct interest expense?
Regardless, you’ve still put together a nice little spreadsheet. Factoring in all the subtleties (amortization, for example) is typically more effort than it’s worth. You just want to make sure you’re not missing anything big.
