Originally Posted by
545GAlady
Ok thanks! We are short on return on the whole system, with only 7 8 inch returns. There's a total of three ducts coming off the return box which two of them are 10 inch. The other one is either 10 or 12 inch (most likely 10). The contractor mentioned that another return will have to be added, but it can't be added through the wall unless its a new construction, according to code. A new return will have to be installed in the floor. The current returns are located low on the sidewall. A 3.5 ton system needs 1400 cfm,and our current furnace has a 4 ton blower which can go up to 1600 cfm. I'm surprised he didn't exactly say what size return should be added. What do you think? Unfortunately, I don't think we're able to downsize on the furnace since the heat pump is 3.5 ton, which requires 1400 cfm. Is there is a brand that has a 70,000 BTU furnace with a 4 ton blower? Our current furnace sometimes short cycles. It heats up the floor in short period of time.