With three days of more than 100-degree, potentially record-breaking heat on the horizon for Colorado, Colorado energy bills are ready to skyrocket. Here’s how to save money during the extreme heat. Home cooling can account for about half of most consumers’ summertime electricity bills, according to Xcel Energy officials. To use less energy and save money, the energy service provider said customers should: Close the blinds or shades to keep rooms cool during the day. Open interior doors to help circulate cool air throughout the house and use weather stripping to seal exterior doors and windows to prevent cool air from escaping. Improve the insulation of walls, crawl spaces, floors and vents.