Hi all I'm new here. I am adding a second floor to my 1450sqft ranch home addition will be 672 sqft and was wondering what I will need to run for forced air heat. My furnace is a lennox pulse model # G1 403-80-19 80,000 btu the hot air runs are 6 inch dia. tubes there are three registers in the same area directly under the addition. Do I run one big tube up and split to three or run three separate ducts. Any help is appreciated.
Didn't realize no one replied to you, My reccomendation at this time would be to bring in a HVAC contractor and explain to him what you are wanting to do, its hard to tell what trouble you could get into by doing this without consulting a professional. Most of us give free estimates, and alot of time if you buy the stuff from that contractor they will help you DIY. Just one last note, you have an excellent furnace, but it has to be tuned up every other year with a new ignitor, flame sensor, intake flapper and condensate trap cleaned. If you have not kept up on that you might want to get the heat exchanger pressure checked, it takes a special kit to do this, leave that one to the pros.