Question

A homeowner is considering these heating systems for heating his house: Electric resistance heating with $0.12/ kWh and 1 kWh = 3600 kJ, gas heating with $1.24/therm and 1 therm = 105,500 kJ, and oil heating with $2.3/gal and 1 gal of oil = 138,500 kJ. Assuming efficiencies of 100 percent for the electric furnace and 87 percent for the gas and oil furnaces, determine the heating system with the lowest energy cost.   

Answer 1

Unit cost of useful Energy Energy supplied cost conversion efficiency gas heater unit cost = $1.24 (4 ) | $13.5 X106 KJ Ar = lowest cost heating by oil heater's 0-87 -105,5oo) Unit Costa $2.3 x- 0.92 (138500/ 19.1x10-6/K5 Ano Electric heater quit costa $ 0.12 xl 1 (3600) $33.3 X106 kJ AS Lowest cost is natural gas heater As