a building is being renovated, including replacing windows with standard quality windows. a higher efficiency replacement window is available and costs $200 per window. the building has ten windows. compared to the standard model, if the higher efficiency model is used for all the windows, the annual gas savings from reduced heating costs are expected to be $150 a year and the annual electricity savings from reduced cooling costs are expected to be $100 a year. what is the simple payback? if we use a time-value-of money approach with an interest rate of 5%, how long would it take to break even? simple: 8 years tvm: 10.5 years simple: 0.8 years tvm: 1.5 years simple: 40 years tvm: 21 years simple: 8 years tvm: 9.5 years