have you looked into warming the floors in your family room? we have products for under carpet,wood and hard surfaces like tile or stone. if you would like to get some more info lookup www.WarmFloorCenter.com We have a gas heating system for the house and warm floors in the living,din/kit and baths. we do keep the gas bills down to $40-50 a month for a 2750sq/ft house. our power runs $135-155 and thats all elect except the furnace. do insulate with a reflective faced insulation. that will help keep your heat in the room. good luck with your project.