I would start by placing an exterior room. I have several posts outlining how to do this on the forum, so start there if you don’t already have one.
Once that is done you can query the boundaries of any room. So start by getting all rooms, and filter out any which are conditioned using a filter by bool mask method. The remaining rooms would all require thermal isolation for any wall, ceiling, or floor which bound them. The API, some out of the box nodes and a few nodes in packages (Clockwork, Archi-lab, I think Genius Loci, and others) allow querying room boundaries, so you can use the queried results to check for isolation.
Now this may return some false positives where unconditioned rooms are adjacent to other unconditioned rooms, but it is a good start!