Hi All, As soon as I get all the junk out of there, I'm going to be starting on my basement finish project. So, you'll probably be hearing a lot more from me over the next few months. :) Thought I'd start with a quick question. Has anyone ever tried using a Rotozip to cut holes for the takeoffs in the main trunk? I was thinking this might be easier than using snips, but I'm not sure if a standard Rotozip bit will cut through the sheet metal. Scott

I am hoping to get some feedback or advice on my planned ducting for a new furnace. It is a Goodman GMV90905DXA (90,000 BTU input on high stage), which I will hook up to existing supply ducting in the attic. The return ducting will be all new, and will consist of a centrally mounted grille, with filter(s) housed behind it, and a duct(s) leading back to the furnace. The combined supply duct area is about 420 sq in, or 2.9 sq ft. The furnace will only be used in heating mode, as I don't have or need an A/C. Here are some of my questions: 1. Does the supply ducting seem about right? With 2000 CFM and 2.9 sq ft, that's about 690 FPM through the supply ducts, which is close to the 700 FPM I saw recommended. Or is 2000 CFM too high for heating only? 2. The Goodman manual recommends 960 sq in of filter area, to give 300 FPM at 2000 CFM. So would this mean (2) 20"x24" filters? Would that require two 20x24" grilles? 3. I was going to try for about 500 FPM in return duct, so at 2000 CFM, that's 4 sq ft, or 576 sq in. This would require one 27" duct or 2-18" ducts. Is that right, or is that overkill? 4. Finally, this has me confused - the manual says to adjust blower speed at start-up until the correct temperature rise is obtained - but I need to size the ducts now based on the blower speed, without knowing what the final heating blower speed will be. So should I just use the worst case speed (2000 CFM) like I have been doing? Thanks in advance for any help and suggestions. Leon