Replacing your windows during the weeks leading up to summer will help you prepare for hot weather. Worn or old windows not only let in the cold during winter, but they also allow the hot air in during the summer. If you have air conditioning, you will notice that your electric bill will be fairly higher than it could be with new, energy-efficient windows. Energy-efficient windows have multiple chambers in the frame and at least two panes of glass to help maintain a comfortable temperature in your home or office. In addition, new windows will also make your home more aesthetically pleasing and increase the value of the property.