Rental property - asset depreciation

Basically, 100% depreciation gives you the same net effect as claiming the furniture as a miscellaneous expense. Either way, you are taking 100% of the tax benefit on this return (the 100% depreciation is really the best route, though). 

Regarding the added overall expense impacting your tax due, it sounds like you may have refundable credits on the return that are being negatively impacted by the overall decrease in income. 

One way to check on this is to look at your forms WITH and WITHOUT the furniture added. This will help you pinpoint what part of your return is being impacted. Here's how to look at your current-year return forms:

• In the left-hand menu bar, click on Tax Tools, then click Tools.
• Under Other helpful links, click View Tax Summary.
• Your Tax Summary will be displayed. In the left-hand menu bar, you will see a new option: Preview My 1040. Click it, and this will allow you to see the forms. It is important to check your 1040 before you check your state return, as much of your entries on the 1040 will impact the state return.
• If you want to view your state entries, Click on Tax Home in the left-hand menu bar. In the center of your screen, scroll down until you see State Taxes. Click on it to review your state entries.