What are you calling "coverings"? If you mean shutters or awnings that are physically attached to the outside of the windows, then I see that as "a material part of" the property, unless you intend to remove them if you sell the property. If you're talking about curtains or window blinds inside, then no.
Keep in mind that since you're setting this up for the first time in TurboTax, you don't need to list each property improvement separately. (Unless you want to.) Here's an example:
Purchased house for $100,000 on Jan 1, 2018.
Paid $10,000 for a new roof in Feb of 2018.
When entering the house in the SCH E section of the program I'll work it through as the program is designed for me to work it through. Then when I'm done with that, I'll go into the Assets/Depreciation section of the program, elect to EDIT the rental property asset and start working it through. On the screen titled "Review Information" you see several boxes for data there. One is "Cost" which is what you paid for the property after all your deductible sales expenses were taken off. So for me it may show a cost of $95,000. Since I paid $10K for a new roof after I purchased the property and before I placed the property "in service", I can just add my $10K paid for the roof to the total "Cost". So I'll change the $95K to be $105,000. Any property improvements done prior to you placing the property "in service" can be added to that "Cost" total. But under no circumstances will you change the "Cost of Land" amount.
Why can you do it this way? Because, the rental property and all of it's improvements are placed "in service" at the same time, regardless of when you actually paid for that property improvement.
Now any property improvements I do "after" the property has been placed in service, must be entered separately in the assets/depreciation section and those improvements will stand on their own, since their "in service" date would be after the property itself was originally placed in service.
