Today I found a bug related to window construction of E+. When I added an adiabatic window construction (with very low solar transmittance, very high solar reflectance and very low conductivity ) into a residential building IDF file, even though I did not use this adiabatic window construction for fenestration (just keep this construction in the IDF file), I got different building energy simulation results from the case that did not include the adiabatic window construction in the IDF. In other words, the window construction itself could affect the building energy simulation results even though I did not use this window construction in fenestration (FenestrationSurface:Detailed) at all but just include it in the IDF file. That is unbelievable. The difference is about 2%.

I tested this problem using E+ 8.5 and E+ 8.6. If you guys need more detailed info, I can share my IDF file with you for finding out the problem.