Useful Info

Condensation is a direct result of interior humidity and the difference between indoor and outdoor air temperature. If you keep the humidity in your house low, then the likelihood of experiencing condensation is also low. However, the efficiency of your window will also impact the temperature and humidity level at which condensation occurs. Energy efficient windows will help reduce condensation. Here’s why – high performance windows with low U-factors result in inside glass surface temperatures much closer to the room air temperature. Windows with non-metal frames and more thermally-efficient spacers in the dual-pane glass units are also less likely to have condensation on the frame or at the edge of the glass.   Also, realize that in certain conditions (such as humid mornings after a clear night sky), some highly insulative windows may have dew on their outside surface. These windows are such good insulators, that dew is condensing there just like it does on an insulated wall. Well to put it simply, a U Value is the measurement of the rate of heat loss through a material.   Which means that in all aspects of home design one should strive for the lowest U Values possible because the lower the U Value, the less heat will be needlessly escaping. A single glazed window with standard glass will have a typical centre pane U Value of 5.6, while a double glazed window with standard glass will have a U Value of 2.8 The calculation of U Values can be quite complex as it is measured as the amount of heat loss through a 1 square meter of material for every degree difference in temperature either side of the material.   It is indicated in units of watts per square meter per degree Kelvin or W/m2K.   Kelvin is used as the scale of temperature difference, but this is numerically equal to degrees celsius.

SC is a value that determines one type of thermal performance of a glass unit (panel or window) in a building. It is basically the ratio of solar gain (due to direct sunlight) passing through a glass unit to the solar energy which passes through 6mm thick Clear Float Glass . It is referred to as an indicator to how the glass is thermally insulating (shading) the interior when there is direct sunlight on the panel or window. The shading coefficient (SC) depends on the colour of glass and degree of reflectivity. It also depends on the type of reflective metal oxides for the case of reflective glass. Sputter-coated reflective and/or sputter-coated low-emissivity glasses tend to have lower SC compared to the same pyrolitically-coated reflective and/or low-emissivity glass. It is usually a value ranging from 1.00 to 0.00, but experiments show that the value of the SC is between 0.98~0.10. It is known to designers and architects that the SC value plays a significant role in the selection of glass, especially at high-temperature areas. Usually at those areas, low SC is needed to lower the solar heat gain through the glass. It works with the direct sunlight, and with the absence of sunlight SC loses its significance in design.