Windows provide views, sunlight, ventilation, and solar heating, but they also let 10% to 25% of your heating leak outside.
Because the glass in the window doesn’t hold in temperatures as well as your walls, consider caulking and sealing around them to fill any air leaks.
If you live in a warm climate, install tinted window films on south- and west-facing windows that get the most heat gain. For better performance, consider installing an awning or overhang on really hot windows.
Tip: Planting a tree in front of the window provides shade and makes your home more attractive.
If you live in a colder climate, install plastic sheeting to cover the window and keep out any drafts. For even better performance, have storm windows installed. It costs more, but you’ll be much more comfortable in the winter.