Commonwealth Edison (ComEd) an energy services company that provides electricity to more than 3.3 million homes in Northern Illinois marked the beginning of summer by reminding its customers to use energy efficiently during hot humid days as they use energy to cool their homes. To keep their monthly bills as low as possible all summer, ComEd encouraged customers to follow some simple energy efficiency tips. ComEd also has other information on its website about saving energy and money. Another section lists energy saving tips for renovations. Owens Corning also reminds homeowners that they can save energy in the summer by adding another blanket -- of insulation, that is.