Editing Passive solar building design (section)

==Design tools==
Traditionally a [[heliodon]] was used to simulate the altitude and azimuth of the sun shining on a model building at any time of any day of the year. In modern times, computer programs can model this phenomenon and integrate local climate data (including site impacts such as [[shadow|overshadowing]] and physical obstructions) to predict the solar gain potential for a particular building design over the course of a year. [[GPS]]-based [[smartphone]] applications can now do this inexpensively on a hand held device. These [[design tool]]s provide the passive solar designer the ability to evaluate local conditions, design elements and orientation prior to construction. Energy performance optimization normally requires an iterative-refinement design-and-evaluate process. There is no such thing as a "one-size-fits-all" universal passive solar building design that would work well in all locations.