10-4. A retrofitted space-heating system is being considered for a small office building. The system can be purchased and installed for $150,000, and it will save an estimated 240,000 kilowatt-hours

(kWh) of electric power each year over an eight-year period. A kilowatt-hour of electricity costs $0.15, and the company uses a MARR of 10% per year in its economic evaluations of refurbished systems. The market value of the system will be $18,000 at the end of eight years, and additional annual operating and maintenance expenses are negligible. Use the benefit–cost method to make a recommendation. (10.7)