“The benefit of installing blinds is two-fold. First, of course, blinds block sunlight from entering the room and heating it up. Second, especially when using energy-efficient varieties, blinds trap a pocket of air between the window and the window treatment. This creates an insulating effect that helps to keep temperatures in the room much more stable—quite literally, blinds keep energy from flying out your window.
With blinds on your windows and interior temperatures stable, cooling the home using an air conditioning unit or a ceiling fan requires less energy because the equipment doesn’t have to work as hard to achieve the desired effect. It also allows you to set your thermostat higher when you’re away from home because you won’t have to wait as long, to lower the temperature to a comfortable level later on.”