Ladybug psychrometric chart / passive solar heating question

I am using the powerful psychrometric chart component in Ladybug, but have a question that I can’t seem to find an answer to online.

The passive solar heating strategy seems to have a mind of its own. I was using the GitHub file posted by Chris from 2018 (

When you check Passive Solar Heating, the “comfort zone polygon” is huge, but the “strategy percent of time” reads as a small number (< 3%.). Also, it seems that when Internal Heat Gain is turned on (checked), Passive Solar Heating changes (%’s, as well as the polygon). The data seems to show this as well when viewed in a 3D comfort hours chart (the charts that show a spread of red—comfortable—over time of day for the year).

Any ideas what may be happening? Has anyone come across this before? I’ve attached the script here in case that helps. It is a slightly tweaked version of Chris’s file from GitHub. (psychchart component is clustered)

Thanks for any assistance you may be able to provide - this component is really awesome and is a great starting point for all projects.

7-3_psychrometric (127.2 KB)


Hi @martin88smith, please post your Ladybug Tools related questions to Ladybug Tools forum:

whoops, sorry about that. didn’t realize there was a separate forum