Glass Roof U Value

Double glazing with 16 20mm gap 3 0.

Glass roof u value.

Triple glazing with 16 20mm gap 2 2. Obviously improving the individual u factors in the calculation will improve the overall thermal performance. 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. 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.

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. Example of how u values work. 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. 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.

This glass specification will produce a glass unit with ug value of 1 0 1 1 w m 2 k. There are various ways of improving the uw value of an installation. It is proposed to use mineral wool insulation between and over the joists with a thermal conductivity of 0 04 w m k. U value has an inverse relationship to r value.

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.