How to interpret a Performance Datasheet?
When an inquiry is received, King Glass will offer a combination of glass solution based on client’s glazing specification. There will normally be a performance datasheet provided based on the specifications. There are various parameters on the performance datasheet, among which Visible transmittance, SHGC(SC), and U-Value are considered key indicators of the performance of a specific glass product. 
Visible Light

SHGC
U-Value
Also known as the U-factor or coefficient of heat transmission, a measure of the rate of non-solar heat loss or gain through a material or assembly. U-values gauge how well a material allows heat to pass through. The lower the U-value, the greater a product’s resistance to heat flow and the better its insulating value. The inverse of (one divided by) the U-value is the R-value.

U-value is expressed in units of W/m2 °C or Btu/hr-sq ft °F. In the US, values are normally given for NFRC/ASHRAE winter conditions of 0°F (-18°C) outdoor temperature, 70°F (21°C) indoor temperature, 15 mph wind, and no solar load.
U-values are often quoted for windows and doors. In the case of a window, for example, the U-value may be expressed for the glass alone or the entire window, which includes the effect of the frame and the spacer materials.
To reduce U-factors, often a low-e coating is applied to glazing. Low-E coatings reduce heat loss, improving both heating and cooling performance. Windows can also be assembled to improve thermal performance. Some assembly strategies include using two or more layers of panes or films, low-conductance gas fills between the layers, and thermally improved edge spacers, which are placed between the panes.
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