Thermal shades and draperies are very effective for insulating windows and improving comfort. The shades, draperies, or shutters are more effective if they are airtight or custom fitted, because they create a dead air space between themselves and the glass. The airtight seal also prevents warm, most indoor air from depositing condensation on the window glass.
The energy efficiency of window coverings is measured in R-values, like insulation. The higher the R-value, the more it will protect your home from heat loss. A shading co-efficient is an important measurement for summer cooling, and it indicates the window covering’s ability to shade against heat gain. The lower the number, the more effective the shade will protect your home from the summer sun.