NRCA's EnergyWise Roof Calculator Online is a web-based application that provides a graphical method of constructing roof assemblies to evaluate thermal performance and estimated energy costs under normal operating conditions. Developed in 2007, EnergyWise Roof Calculator Online has been updated to include information from the most recent versions of the International Code Council's International Energy Conservation Code (IECC); the International Green Construction Code (IgCC); and ASHRAE Standard 90.1, "Energy Standard for Buildings Except Low-Rise Residential Buildings" (ASHRAE 90.1).
In addition, NRCA has included revised minimum long-term thermal resistance (LTTR) values and its latest recommendations for minimum R-values for polyisocyanurate insulation in the application. This most recent update also offers a new feature—the application now can determine the temperature gradient through a roof assembly and present the information graphically on a report. Users will find this feature beneficial when evaluating a vapor retarder's effectiveness.
EnergyWise Roof Calculator Online is a free, web-based application that provides a graphical method of constructing a roof assembly to determine the overall R-value; the minimum R-value requirements for a selected code or standard; and estimated energy costs attributed to a roof assembly under normal operating conditions.