Need expert opinion

[lmsmedley]

We have a two-story 3200 sq. ft. house with a 5-ton and 3-ton unit. The 5 ton works on both levels and does a fine job on its own. The 3-ton is nice to have on those really hot days because it really helps cool the upstairs.

The 3-ton died. Both furnaces are in great shape. Besides replacing the 3-ton, here's what we're considering:

Our family room does not have a register. It could use one, although it isn't essential, it would be nice. Needs about 200cfm.

The AC company made several suggestions. One is a mini-split that'll cost $5000. No way. Another is that we may just wait until we replace the windows in that room and stick in a wall unit.

But here's one other possibility:

Upgrade the 3 ton to a 3.5 or 4 ton.
Run a duct from the attic down the side of the house into the family room.

Questions:
If we do this, must we:
1) Upgrade the furnace?
2) Upgrade the refrigerant lines with a line set cover?
3) Upgrade the cooling coil?
4) They suggest using the Lennox 13ACD-048 4 ton Merit Series and
Lennox G40UH-48B-090X 90000 BTU Merit Furnace
Lennox CH33-48C-2F 4 ton Hi eff. cooling coil with TXV.

Many many many thanks!!!!!

[tn a/c man]

When you say furnace died do you mean indoor or outdoor unit.

[comfortdoc]

I think load calculations are in order before you do anything. Seems like you have a lot of cooling for your home.

[lmsmedley]

It's an indoor furnace, in the attic.

What are "load calculations"?

[rickboggs]

ex·pert (kspûrt)
n.
1. A has-been drip under pressure.