Thermal conductivity coefficient – U

Thermal insulation of joint glass and windows is often described by a thermal  conductivity coefficient – U [W/m2*K]. It is the amount of heat which passes in an hour through a plate of particular area and thickness when its opposite faces differ in temperature by one Kelvin. The smaller coefficient, the better insulation of the glass and the window.

The Ug coefficient shows the amount of heat conducted in certain conditions.

Lower coefficient means less heat will be lost through the glass

EXTERNAL TEMPERATURE

INTERNAL TEMPERATURE

Ug 

Amount of the heat conducted