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Sloped Glazing

Both Heat Mirror® Insulating glass and XIR® Laminated glass are designed to address these issues, with particular emphasis on solar control performance.

Project: National History Museum Location: Washington, DC Architect: I.M. Pei FabSolution: Heat Mirror 55/Clear

A less well-known but equally important challenge with sloped glazing is to adequately account for the degradation in insulation performance which affects insulating glass units when they are installed in sloped orientations.

Failure to address this issue can result in unexpected condensation problems and excessive heat loss through sloped glazing areas.

Unlike most high-performance low-e insulating glass products, which lose up to one third of their insulation performance when sloped, Heat Mirror Insulating Glass units experience only a 6% loss of insulation performance when sloped.

Heat Mirror enables higher light transmission and lower reflectivity to be achieved in sloped glazing while maintaining the required level of thermal insulation, compared with conventional low-e insulating glass products.

	A)  Horizontal convective heat transfer in vertical insulating glass plays a relatively minor role due to the long up and down path of circulating gas molecules.
B)  As an IG unit approaches horizontal, convective heat transfer increases as the up and down molecular loop becomes shorter.
	C) The presence of a suspended Heat Mirror Film (blocking the up and down gas-molecule path)  dramatically reduces convection in sloped IG units. For example, a Heat Mirror-66 unit rotated from vertical to 27 degrees loses only 6% of its insulating value.  Soft-coat low-e performance drops over five times this figure, or 31%.