For energy efficiency and passive solar gain, the home uses double-pane, fiberglass-framed casement and awning windows from Inline Fiberglass. All of the RISE windows have a maximum U-factor of 0.28—the lower the U-factor, the greater a window’s resistance to heat transfer and the better its insulating value. The south-facing windows have an SHGC of 0.42 (meaning 58% of solar heat is blocked), and the other windows (east, west, and north) have an SHGC of 0.24 (blocking about 76%). Inside, honeycomb shades or interior shutters further reduce summertime heat gain and provide a small amount of insulation during the winter.
“At the time of window selection, Inline was one of the few companies that made windows that met the solar heat gain coefficient (SHGC) and U-factors required by the home’s design specifications. Other U.S.-based companies have since improved their specs,” Palmer says.