Would a rental depreciation loss on your taxes instead of a gain have a positive affect on your return.

It would be extremely rare.

For the most part (like 99.999% of rental property owners) rental real estate "always" operates at a loss on paper, at tax filing time. If you add up the deductions for mortgage interest, property taxes, property insurance and the depreciation you are required to take by law, those 4 items alone will practically always exceed the total rental income received in the tax year. Add to that the other allowed rentals expenses such as repairs, cleaning and maintenance and you're practically guaranteed to show a loss every single year, on your tax return.

Now rental income is passive. So rental expenses are passive also. You can only deduct your passive expenses from the passive income. Once those expenses get your passive income to zero, that's it. Any leftover expenses are just carried foward to the next year. So with each passing year your carry over losses continue to accumulate and increase.

Then in the tax year you sell the property, that's when  you can "realize" all those losses and deduct them. It works like this:

 - First, all prior depreciation is recaptured and gets taxed at a maximum of 25%. Consider that recaptured depreciation as a reduction of your original cost basis on the property and it's assets.

 - Then your passive losses are deducted from any gain you realize on the sale.

 - If passive losses get your taxable sales gain to zero, and you still have more losses to claim, then those losses are deducted from "other" ordinary income such as W-2 income, up to a maximum of $3000.

 - If you still have passive losses to deduct, then they get carried forward to the next year where they can be deducted from your "other" ordinary income up to $3000 again. This carry over continues until you have used up all of your passive losses.

So for all future years you own this property and rent it out, chances are slim to none that you will "ever" pay one penny of tax on any of the rental income.

If you or your spouse actively participated in the rental, you may be able to deduct up to $25,000 of loss from your nonpassive income (subject to a phaseout).

See https://www.irs.gov/publications/p925#en_US_2018_publink1000104571