Question-and-Answer Resource for the Building Energy Modeling Community
Get s tarted with the Help page
Ask Your Question

I am getting a warning that says: "Both surfaces 'Surface 1', and 'Surface 2 reference the same construction 'Wall Interior 1' but it is not symmetric, creating a reversed copy." What does this mean?

asked 2017-07-13 08:37:42 -0500

Student gravatar image

updated 2017-07-13 08:52:35 -0500

I saw a similar error asked by someone else but there was no explanation as to why this error comes up.

This error came up when I translated my openStudio model to EnergyPlus. What does this error mean? Is there anything I can do to fix it?


edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2017-07-13 08:45:52 -0500

Student gravatar image

I just realized why this error occurs. It happens when a custom construction material is hard assigned to 2 surfaces that are touching. To fix it, delete one of the hard assigned construction materials from one of the surfaces. The program will automatically pick up the construction from the surface's 'outside boundary condition object'.

edit flag offensive delete link more



The problem is not with custom constructions specifically, it's with asymmetric constructions, i.e., constructions with material layer orders that are not the same when read from one side vs. another. If you assign asymmetric construction ABC to matched surfaces in zones 1 and 2, you create an impossible/ambiguous situation. The construction must look like ABC from zone 1 and CBA from zone 2 or vice versa. It cannot look like ABC from both zones. If only one surface is assigned ABC, EnergyPlus automatically creates the CBA construction and assigns it to the matched surface.

__AmirRoth__ gravatar image __AmirRoth__  ( 2017-07-13 09:06:40 -0500 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer


Question Tools

1 follower


Asked: 2017-07-13 08:37:42 -0500

Seen: 92 times

Last updated: Jul 13 '17