Glass Roof U Value

In descending order these are typical u values for glass.

Glass roof u value.

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. Obviously improving the individual u factors in the calculation will improve the overall thermal performance. 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. There are various ways of improving the uw value of an installation.

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. Triple glazing with 16 20mm gap 2 2. 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. U value has an inverse relationship to r value.

For example a building with material with an r value of r 11 converts to an u value of 0 09 1 r or 1 11 0 09. This glass specification will produce a glass unit with ug value of 1 0 1 1 w m 2 k. It is proposed to use mineral wool insulation between and over the joists with a thermal conductivity of 0 04 w m k. Double glazing with 16 20mm gap 3 0.

Example of how u values work.