New HVAC system -- what to choose?
I'm a long time lurker, but really in need of help choosing the right HVAC system. The motor blower died last week on my 17+year old 90000btu gas furnace and 3 ton a/c. I've gotten three quotes (with a fourth expected tonight). I'm reasonably confident that any of the systems proposed will be fine for the main floor. My problem is the 2nd floor, which was renovated after a fire, and the air flow has never been adequate since. The guy that came out today looked in the attic, and noted that there are 3 flex ducts (6" I think) coming off of one 4x12 duct. One of them is fairly short and the airflow is fine, but the other two run into the attic and there is almost no air coming out of them. Since I'm replacing the system, is there anything that can help resolve this? I know it won't be perfect, but on hot days it's about 10 degrees warmer on the 2nd floor than the 1st floor.
One guy said they would use a 4 ton blower with a 3 ton a/c to help push the air. Does that sound reasonable?
Any suggestions are greatly apprecitated -- thanks!