Passive Solar Calculator Sizes the Eave Between Summer Heat and Winter Sun

Field notes

The calculator combines latitude, eave and sill heights, window height, wall thickness, and two seasonal dates to estimate an overhang beyond the wall face. It uses solar-noon elevation derived from latitude and declination, then chooses the lower-angle date as the governing case. The page includes a to-scale cross-section, an annual angle display, English and Spanish options, and a NOAA calculator link for comparison. Its stated scope is preliminary design, with special limitations near the tropics.