A residential building is heated with a 78 percent efficient gas-fired furnace (costing $1,600). The annual heating load is estimated at 160 MMBtu. The cost of gas is $6.00/MMBtu. For the discount rate of 5 percent and a ten-year cycle, determine the following:

a. The life cycle of the existing heating system.

b. If it is worth considering a 90 percent efficient gas-fired furnace that costs $2,800.

c. The variation of the LCC savings between the two systems (the existing system and that proposed in (b)) versus the life of the system for life cycles ranging from 3 years to 20 years.

Conclude.