Using square duct vs. round

[dash]

Round pipe takes less metal ,for the same airflow,doesn't make for any better airflow the sq.,or flex,if it's sized correctly.

[trane]

Round pipe takes less metal ,for the same airflow,doesn't make for any better airflow the sq.,or flex,if it's sized correctly.

The statement round is best for air flow should have been round is the most efficient way to move air. 150 CFM out of round pipe, flex, or square is still the same amount in the end

[mlo1]

If I can believe the original installer the system was to be a 3.5 ton. But a 3 ton was actually chose because of availability.

I just looked at my the contract/invoice. Mr. installer had told me he figured the system requirements to be 3.5 ton. He wrote the Carrier air handler # FV4BNA00500 w/15KW strip heat on the contract. Seems that is a 4 ton unit, so he rounded up as there is no 3.5 ton offered. He made a big deal about this handler as it was an "A" coil, which he said would help with dehumidification.

But he installed a Carrier FV4BNF003000 AAAA air handler with out telling me. Upon inspection, this has a "slant" coil.

If I am interpreting the numbers correctly. It appears the 003 has to low of CFM for my supply needs. And possibly with the slant, may be less capeable of dealing humidity which was high on my list of priorities (bad asthma).

Any insight between the two?

[dash]

Those are indoor units,air handlers,what outdoor unit was installed?

[mlo1]

The intention was to use a 223ANA048. Though when I found out it was the lower line of products, I asked it be upgraded.