The local sales tax rate is applied to the luminaire cost and control(s) cost. If you don't wish to include this in your calculation simply enter a value of zero.

This is the owners income tax rate and it is used in calculation of the 'income tax effect' or 'depreciation tax shield' which depreciates the owner's income tax liability. Straight line depreciation is assumed so the calculation is as follows

The total tax effect value is calculated by using the present value of an annual cost formula with a time period equal to the depreciation years. If you don't wish to include this in your calculation simply enter zero for Income Tax Rate.

This is the number of years over which the system is depreciated. The depreciation may be accelerated depending on tax laws. If you don't wish to include this in your calculation simply enter a value of zero. Use the write off life used by the owner.