Base window selection on solar orientation

Conditions vary on different sides of the house, so order windows accordingly.
On south-facing windows, where winter heat gainIncrease in the amount of heat in a space, including heat transferred from outside (in the form of solar radiation) and heat generated within by people, lights, mechanical systems, and other sources. See heat loss. is a plus, specify low-eLow-emissivity coating. Very thin metallic coating on glass or plastic window glazing that permits most of the sun’s short-wave (light) radiation to enter, while blocking up to 90% of the long-wave (heat) radiation. Low-e coatings boost a window’s R-value and reduce its U-factor. windows with a high solar heat gain coefficient(SHGC) The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. (SHGCSolar heat gain coefficient. The fraction of solar gain admitted through a window, expressed as a number between 0 and 1.). On east and west windows, minimizing heat gain in summer is the issue, so install windows with lower SHGC values and higher R-values (lower U-values). On north windows, maximizing the R-value is important and SHGC isn't much of a concern.

Green points

LEED for HomesLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. : Up to 3 points for windows that meet certain requirements for U-value and SHGC (EA 4).

NGBSNational Green Building Standard Based on the NAHB Model Green Home Building Guidelines and passed through ANSI. This standard can be applied to both new homes, remodeling projects, and additions. /ICC-700: Up to 8 points, depending on climate zone, for windows meeting U-value and SHGC minimums.

Learn more in the Green Building Encyclopedia


Learn more in the Green Product Guide


Further resources

Efficient Windows Collaborative
Residential Windows

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