Solabacus® is a simple calculator for the iPhone and iPod Touch that graphically displays how much clean energy your home can generate using photovoltaic panels in any given location in the USA. The calculation is based on a database of solar radiation from over 1,400 weather stations distributed throughout the United States.

The amount of energy created by a photovoltaic array depends on many factors, such as the latitude, the angle of the array towards the sky (the tilt), the horizontal direction the array is facing (the azimuth), and the ambient temperature. Shade and albedo (locally reflected radiation), which are unique to each site, are additional considerations that need to be factored into the final calculation. Solabacus® should not be considered a substitute for a professional assessment, but it does provide a good indication of how much photovoltaic monthly energy you can expect to generate and graphically comparing this with your estimated consumption.

The Solabacus® database of solar radiation is based on the National Solar Radiation Database TMY3 data set, which is the result of the hourly capture of meteorological data throughout the US over a 14-year period.

Solabacus® also includes a comprehensive database of currently available photovoltaic modules, providing convenient access to their electrical and physical specifications and touch links to their manufacturers' websites.