Cellular shades are a window covering used to block or filter light and insulate windows to save energy. Cell size can vary. Cell shapes hold trapped air and create a barrier between the window surface and the room. Since there is no test for them, they qualify for a US energy tax credit. Windows and doors make up for one-third of a home’s total thermal loss, according to the Natural Resources Defense Council. This applies to heat loss in winter, and entry of undesired heat in summer. When it is in the room, it is cooled or warmed. By convection this air circulates around the room. Cell shapes in the blinds are trapped air and create a barrier between the window surface and the room. Shades, however, provide only slight control of air infiltration. Cellular shades can be constructed as single cell, double cell, or triple cell shades. Single cell fabric has an R-Value between 0.28 and 0.44 (1.6 and 2.5 imperial), and has a metric R-value between 0.49 and 0.70 (2.8 and 4.0 imperial). A 6 mm (¼ “) thick single window has a metric R-value of 0.16 (0.91 imperial). Unlike window blinds, which are made of hard materials, they are made of a soft paper- or cloth-like material. Typically, they are used, but other fabrics can be used during the manufacturing process. In common with all cellular blinds, we can reduce solar gain in summer. Also, they are raised and lowered horizontally with a string.