In 2024, the U.S. Department of Energy purchased the RED online building science tools, both the free version (now called Standalone) and the enhanced Pro version. Both versions of the tools are now free and are available on the Building America Solutions Center website, maintained by Pacific Northwest National Laboratory (PNNL): https://basc.pnnl.gov/redcalc. The tools are officially referred to as the “RED Calc” tools at their new location. Once the RED Calc tools were relocated, they were no longer available on the website you are now on, www.redcalc.com. This article will walk you through most of the details of using the Pro version of the ASHRAE 62.2-2016.