I'm sorry, I did not provide enough info. for a more informed answer.
I have a 3 ton downflow unit,which I am converting to upflow because the floor diffuser ducts are rusted through.
The attic area space is very limited. I was thinking about using the same furnace 'because it is almost new'...
What would be the maximum FPM for a 4way ceiling diffuser in a master bedroom that has 165 SF and no windows ?
Using the 1/1 fpm to cfm ratio, I would need 165 CFM. Should I use two small diffusers or one large one and if so what sizes ?