4-84. A retail outlet is being designed in a strip mall in Nebraska. For this outlet, the installed fiberglass insulation to protect against heat loss in the winter and heat gain in the summer will cost an estimated $100,000. The annual savings in energy due to the insulation will be $18,000 at EOY one in the 10-year life of the outlet, and these savings will increase by 12% each year thereafter. If the annual interest rate is 15%, is the cost of the proposed amount of insulation justified? (4.12)