Inefficient windows allow heat to get into your house in the summer, slip out of it in the winter, and are responsible for up to 30% of a home's heating and cooling bills. If your windows are old or single-pane, you might want to consider replacing them. If they are in good shape or new windows are not in the budget, try updating them to make them more energy efficient.
Inspect your windows for air leaks, caulk around them and install weatherstripping. Apply weatherstripping to areas that can handle friction and weather changes, and apply caulk on the sides and joints of your window frame and other window areas.
For south and west-facing windows, adding awnings is a smart choice. Awnings on south-facing windows can reduce the amount of solar heat gain in your home by as much as 65% in the summer. Awnings used on west-facing windows can reduce it by up to 77%.
Window blinds and thermal drapes can reduce heat gain by up to 45%.
Window films can block up to 35% of solar heat and 95% of ultraviolet rays on a hot summer day. This is a fairly inexpensive DIY project. Find more energy savings tips here.