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Engineering Economics Focus on the difference between feasible alternatives (Pri

ID: 2816794 • Letter: E

Question

Engineering Economics

Focus on the difference between feasible alternatives (Principle 2)! Insulated concrete forms (ICF) can be used as a substitute for conventional wood framing in building construction. Heating and cooling bills will be about 60% less than in a similar wood-framed building in upstate New York. An ICF home will be approximately 20% more expensive to construct than a wood-framed home. For a typical 2.100 ft home costing $130 ft to construct în upstate New York and costing $280 per month to heat and cool, how many months does it take for a 2,100 ft2 ICF home to pay back its extra construction cost?

Explanation / Answer

Construction cost of ICF home = 2100*130 = 273000

(which is 20% more than wooden frame home)

Construction cost of wooden frame home = 273000/1.2 = 227500

Extra cost of construction = 273000 - 227500 = 45500

Heating and cooling expense for ICF per month = 280

(which is 60% less than wooden frame)

Heating and cooling expense per month for wooden frame = 280/0.4 = 700

Savings from heating and cooling bill = 700- 280 = 420

No of months to payback extra construction cost = 45500/420

   = 108.33