Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
It is not a bug in OS nor anything you are doing wrong. EnergyPlus itself cannot model a U-value higher than 5.8 W/m2-K. The reason for this is that there is some thermal resistance in the surface-to-air interfaces and with standard film coefficients the U maxes out at about 5.8. To go any higher there would need to be 3-D fins, a tall curb, or projecting glazing to augment heat transfer, but in EnergyPlus the windows are flat planes. I believe most reviewers understand this and you can just go with the highest value the software can use.
