%0 Conference Paper
%A Yu Joe Huang
%A Robin Mitchell
%A Stephen E Selkowitz
%A Dariush K Arasteh
%A Robert D Clear
%B SimBuild 2004
%C Boulder, CO
%D 2004
%G eng
%L LBNL-55517
%T Development of Trade-Off Equations for EnergyStar Windows
%1 <p>Windows and Daylighting Group</p>
%2 LBNL-55517
%8 08/2004
%X <p>The authors explore the feasibility of adding a performance option to DOE's EnergyStar© Windows program whereby windows of differing U-factors and SHGCs can qualify so long as they have equivalent annual energy performance. An iterative simulation procedure is used to calculate trade-off equations giving the change in SHGC needed to compensate for a change in U-factor. Of the four EnergyStar© Window climate zones, trade-off equations are possible only in the Northern and Southern zones. In the North/Central and South/Central zones, equations are not possible either because of large intrazone climate variations or the current SHGC requirements are already near optimum.</p>