NAME: _______________________________________ DATE: _____________ CLASS: ______________ HOME ENERGY AUDIT: ENERGY EFFICIENCY WORKSHEET Calculating Lifecycle CostsHow much will an appliance cost to buy and use over a lifetime?
Calculating Payback PeriodHow long will it take to recover the extra money you spend for a more efficient appliance?
Problems: You would like to buy a new refrigerator and are looking at two different models. 1. If model A uses 700 kWh/year, how much is the yearly operating cost (based on a cost of $.089 per kWh)?700 kWh/year x $.89 /kWh = $62.302. What is the lifecycle cost of model A if it cost $789? lifecycle cost = purchase price + (yearly operating cost x estimated lifetime x discount factor)3. If model B uses 900 kWh/year, how much is the yearly operating cost (based on a cost of $.089 per kWh)? 900 kWh/year x $.089 /kWh = $80.104. What is the Lifecycle cost of Model B? ($80.10 x 20y x.76) = $1217.52 $700.00 + $1217.52 = $1,917.525. If model A costs $789 to buy and model B costs only $700, what is the payback period? (Difference in purchase price) / (Difference in annual operating cost) = payback period |
Created for the NTEP II program
on behalf of the National Renewable Energy Laboratory in Golden,
Colorado.