A: Cellular shades are great because they help insulate your windows against energy loss as well as sound. They act a lot like double-pane windows by trapping air between their layers, becoming an insulating barrier.
Cellular shades actually have small tunnels of air that expand as you close the shades. Each of these little tunnels helps keep warm air in during the winter time and blocks some of the sun's heat in the summer. They're especially nice for windows that get a lot of direct sunlight during the summer months and can even help muffle the sound of your neighbor's parties, too!
Keep in mind that cell counts and sizes have a lot to do with how well a cellular blind insulates your window. Take a look at my other post here to find out more about cell counts and click here to find out more about cell sizes.