How do I calculate heating demand for a rooms in a house when trying to do duct work?
Lots of in-depth calculations required to size equipment and ductwork. Heat loss calculation required for equipment size. Another set of calculations to size the ductwork. Best bet is to ask for help from supply house. They will most likely size equipment for you, but ductwork is another story. It’s a lot more work than most people think. The supply house may suggest a fabrication contractor for you. They could make up the ducts and you could save money by self installation. If you wanna give a shot on your own, check out this site for load calcs: http://www.heatload.com Ductwork: http://www.hamiltonhomeproducts.
