According to the Energy Savings Trust, 18% of heat loss in homes occurs through windows. Blinds and shutters can help to reduce heat loss.
New independent research at the University of Salford’s Energy House Laboratory has demonstrated that blinds and shutters can reduce heat loss through windows by up to 33%. The results of product tests showed that centre pane U-value measurements on a modern double glazed low-e window improved by 33%, compared to the same window with no covering.
Conduction is the transfer of heat through direct contact. When warm air from inside your home comes into contact with the cold glass of a window, the heat is conducted away from the air and into the glass.
Convection is the transfer of heat through the movement of fluids. When warm air from inside your home comes into contact with the cold glass of a window, the air molecules cool down and sink. This creates a convection current that pulls more warm air from inside the home to the window, where it is cooled and sinks again.
Radiation is the transfer of heat through electromagnetic waves. The glass of a window is transparent to visible light, but it is opaque to infrared radiation. This means that heat from inside your home can pass through the glass in the form of infrared radiation, but it cannot pass back through the glass.