Your home has an existing 80% efficient natural gas furnace, and gas prices just rocketed from $1/therm to $2.50/therm. Last heating season, you needed 650 therms of gas to supply your heat. An electric heat pump is available to provide your heat at an EER of 14.8, and electricity costs $0.215/kwh. How much money will the heat pump save you in operating costs next winter, if you need the same amount of heat ($/season)?