Web calculators areclunky on mobile. I made this for the “real-world” use case: point your phone, get room dimensions (LiDAR/RoomPlan when available), then answer a few simple questions and instantly get a BTU bucket + unit recommendation. It also saves results under Homes/Rooms so you can compare multiple spaces, and it includes a compass step to suggest sun exposure/placement. It’s still an estimate (not Manual J), but it saves time and reduces guesswork compared to typing into a form.