Depreciation on 1 unit of a fourplex

[Ryan Wamsat]

I read somewhere (couldn't find it again, for reference) that if I replace an item, such as an AC, in one unit of a fourplex, I can capture 100% depreciation in that tax year.  The logic being that I replaced only 25% of the ACs in the building.  Therefore, since it wasn't a material change, it can be fully depreciated immediately.

Is there any truth to this?