Understanding just how much sunlight falls on a home’s roof can help a homeowner make conclusions concerning roofing materials, insulating material and also the placement of solar panels. Calculating the quantity of sunlight that falls onto a roof is a intricate process, but several tools make it possible for homeowners to determine a roof’s sun exposure with varying degrees of ease and precision, depending on the instrument.
Straightforward online calculation tools will permit a homeowner to find out the average number of sun-hours experienced in a particular location; other online calculators can determine the angle at which a roof surface or solar panel must be positioned to be able to get the optimum quantity of sunlight at the location, based on the location’s latitude. These calculators only give typical values for any given location, however, and the consequences don’t take into consideration the roof’s specific construction or the position of trees or other objects that cast shade on the roof.
Manual solar accessibility analysis tools such as the SolarPathfinder enable users to precisely calculate the solar exposure of a specific construction. The SolarPathfinder is a transparent plastic world the user levels and positions on-site together with a template. The user can then browse through the reflective world and trace the website’s shade horizon onto the template; the resultant profile will indicate precise data concerning the site’s solar exposure. Supplementary software, when used along with the manual tool, partly automates the process.
Electronic solar analysis tools, such as Solmetric Corporation’s SunEye program, combine the functionality of a manual tool with integrated software that analyzes the data gathered by the instrument and produces a solar exposure record. The user speeds the unit and takes a photograph of the site with the built-in electronic camera; the unit then generates data that indicates the site’s solar access at different times of day and at different seasons. The data can also be uploaded to your personal computer for further analysis.
Geographical Information Systems
Online systems have been developed that will compute solar exposure for certain roofs based on actual climate and geographical data. These systems will take into consideration the actual physical surroundings of a certain roof instead of simply create average values for a location. As of November 2012, however, these tools were accessible only in very specific and restricted places.