You could also define this as a window construction assembly. For example, if the original or old window is single-pane, and the new window is double-pane, then you could define the final window assembly as (ordered from outermost to innermost layers):
If you want to explore the impact of installing the new double-pane window on the inside rather than the outside, then the layers of the construction above would be switched.
OK. What are often called storm windows. Look up the EnergyPlus WindowProperty:StormWindow object. It's pretty straightforward. Unfortunately, I don't think the OpenStudio SDK supports this feature. You're likely left with either:
EDIT, in response to the follow-up comment:
For greater flexibility (e.g. exterior storm window vs extra interior pane), you can always look into the following EMS features to dynamically switch a subsurface's construction:
The EMS "thermochromatic window" example was implemented as an OpenStudio measure 8 years ago. I couldn't get to work after a few tries. Haven't taken a deeper dive, though. However, it does provide step-by-step EMS guidance on how to implement something similar. May help.
Thank you so much. I think this will work for me. I also want to analyze the case of having the secondary window inside. I do not think I could implement it in the same way.
Asked: 2026-02-05 13:59:45 -0600
Seen: 120 times
Last updated: yesterday
What do you mean by "secondary window"? Like a clerestory window? If you're indeed referring to a window subsurface, how are you usually adding windows in OpenStudio? With the SketchUp Plugin, or FloorspaceJS?
Not a clerestory window. I mean adding a secondary exterior window in front of an existing window without removing or retrofitting the original one.
For example, in an old house where the existing window cannot be replaced, an additional window is installed on the outside, creating an air gap that acts as a thermal barrier. I’m trying to represent this configuration in OpenStudio.