Does anybody know if EnergyPlus uses full (or partial) spectral properties of translucent materials and glass to calculate solar transmission (and associated gains)? Attached C:\fakepath\Spectral properties of polycarbonate.png for instance is the transmission of a poly-carbonate surface that I am modelling as a function of varying wavelength. I noticed that DesignBuilder (that I use as graphical interface) allows me to edit a fairly detailed spectral data library for fabric opening materials, and I am wondering if this gets used in E+ for simulations, as opposed to only static figures that asign a single value to infra-red, solar and visible properties of glass, films and polymers? Thanks a lot Roy