=+9-2.

energy would be required in kW-hr, assuming a 100 percent efficiency factor? If the electrical energy costs 10 cents per kW-hr and natural gas costs $4.5 per mef, what are the relative heat-

ing costs? Assuming a power plant efficiency of 33 percent, compare the total amounts of energy in terms of mef of gas required to heat the building using a gas furnace and an electric furnace.