Fill a teakettle or saucepan with enough water to completely cover the tea bags, about 2 cups. Bring to a boil and remove from the heat. Let the tea stand for 10 minutes. Put the sugar into a gallon pitcher and add 1 cup of cold water. Stir to mix slightly. Pour the hot tea into the sugar mixture and stir until the sugar is dissolved. Stir in the remaining 13 cups of cold water to fill the pitcher.