In the past few years, documents to standardize and eventually codify IEQ measurement and performance have been written. In the United States, the ASHRAE/CIBSE/USGBC Performance Measurement Protocols for Commercial Buildings [24] and the Performance Measurement Protocols Best Practices Guide [25] add to the scope of the European standard EN15251 (2007), which provides guidance on IEQ measurement, standards, and input values to use in energy simulation software.