Window Performance 4 – Dealing with Edge Losses

Energy Solutions: Window Performance 4 – Dealing with Edge Losses

Over the last three weeks I've focused on the major strategies for improving the energy performance of windows : adding extra layers of glass, increasing the thickness of the airspace between the layers of glass, adding low-emissivity Amount of heat radiation emitted from a particular body or material. Emissivity is expressed in a fraction or ratio, with the lowest values indicating low emissivity and the highest indicating the high emissivity of flat black surfaces. coatings, and replacing air with a low-conductivity gas fill. These strategies all help to reduce heat flow through an insulating glass unit (IGU), and if we do a really good job with these strategies we can achieve center-of-glass R-values of R-5 or higher. But these measures don't do much to improve the energy performance at the edges of an IGU. In the olden days, when windows were single-glazed and wood-fra...

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