Glass Roof U Value

In descending order these are typical u values for glass.

Glass roof u value.

All insulated glass from iq is specified to this standard as a minimum. It is proposed to use mineral wool insulation between and over the joists with a thermal conductivity of 0 04 w m k. You can expect a standard double glazed panel to have a u value of around 3 w m2k whilst a triple glazed panel with xenon filled cavities and low e coatings will have a u value of around 0 4 w m2k. The u value of a single sheet of glass as found in a traditional window pane is 6 0w m 2 k which means that for every degree of temperature difference between the outside and the inside a square metre of the glazing would lose 6 watts.

Reference table for u values u value is the coefficient of transmission i e the transmission of heat through the materials which compose the building s envelope or outer shell. So for example if the temperature difference on a typical cold day was 15 degrees then the amount of heat loss would be 15x6 90 watts per square metre. There are various ways of improving the uw value of an installation. U value has an inverse relationship to r value.

Triple glazing with 16 20mm gap 2 2. Technically u values are calculated as the amount of heat lost through one square meter of glass for every degree difference in temperature either side of the glass. Determine the thickness of the insulation layer above the joists required to achieve a u value of 0 20 w m2k for the roof construction shown below. Example of how u values work.

Double glazing with 16 20mm gap 3 0.