Where does “sunroom” come from?

I need to work through this chain carefully, but I notice some significant issues that make it impossible to write an accurate etymology statement. The chain provided appears to have errors: - It jumps from "English room" to "Japanese 寸" (which means "sun" or a unit of measurement), but there's no historical pathway from Japanese to English - "Old English synn" means "sin," not related to room/space - The subsequent Proto-Germanic and Proto-Indo-European roots don't coherently support a single word's evolution - The chain seems to conflate multiple unrelated etymologies Since the rules require me to "state only what the chain supports" and "do not invent," I cannot construct an accurate one-sentence etymology from this chain. The chain itself appears corrupted or incorrectly transcribed. Could you verify the etymological chain for "sunroom"? A proper chain should show a single continuous descent

sunroom (English): A room in a residence with numerous large windows...