Can improvements when owning a home be depreciated once it becomes a rental?

Yes. But this may not be a good thing. The conversion to a rental/investment sets the basis for depreciation og the entire property. The amount of gain realized on that conversion would be taxable (unless converted to another residence). You end up forgoing the benefits of owning a residence....probably the biggest benefit available to most people in the tax code. The depreciation is only a timing difference and is repcatured upon sale of the investment and taxed then in any case, at ordinary, not capital gain rates. (Depreciation reduces the basis in the property, so your gain on sale is higher. The rules do not allow you to take depreciation as an ordinary income expense and recapture it as a capital gain, lower rate). Conceptually, it is the same as selling you house and using the proceeds to buy an investment property.