The EnergyWise Roof Calculator Online from the National Roofing Contractors Association (NRCA) now includes information from recent green building standards and energy codes. The calculator, which is available for free on NRCA’s website at, now includes information from the 2010 version of SAHRAE 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, the 2009 version of ASHRAE 189.1, Standard for the Design of High-Performance Green Buildings, and the 2006 and 2009 versions of the International Energy Conservation Code (IECC) from the International Code Council.

The calculator offers an interactive graphic method of constructing virtual roof assemblies to evaluate thermal efficiency. The application denotes minimal thermal insulation requirements established by Standards 90.1 and 189.1 and the IECC, and users also can determine whether a vapor retarder’s placement is effective. The calculator prompts users for specific roof assemble information, such as roof area, climatic region, heating appliance type and cost, roof openings, and roof materials to be used. A report can then be generated to summarize the proposed roof assembly design, estimated heating and cooling costs, and required minimum thermal requirements.