Your building value should be $179,005

which = 230000X (68800/88400), using county tax ratio.

This is the value without land value.

Your depreciation base = 179005 + capital investment (such as furnace).

But different appliance follows a different depreciation schedule.

You'll need to separate them out.

Your house is 27.5 years.

Your appliance may be much shorter.

Refer to detailed IRS tables.