Editing Passive solar building design (section)

====Equator-facing glass====
The requirement for vertical equator-facing glass is different from the other three sides of a building. [[Insulated glazing|Reflective window coatings]] and multiple panes of glass can reduce useful solar gain. However, direct-gain systems are more dependent on [[Insulated glazing|double or triple glazing]] or even [[quadruple glazing]] in higher geographic latitudes to reduce heat loss. Indirect-gain and isolated-gain configurations may still be able to function effectively with only single-pane glazing. Nevertheless, the optimal cost-effective solution is both location and system dependent.