Desperately need advice on mini split vs high velocity for old Georgetown home!

Hello,

I have been tasked with overseeing a project (volunteer) and am totally lost and need some advice.

The house is an old brownstone in historic Georgetown, Washington DC. 2 living floors, attic space, and semi-below ground basement. My GC had an engineering firm come out and give a proposal on installing a mini split system (because they said conventional would be too much construction for ductwork). We did not want the units on the walls, so we brought someone to give a proposal for a high velocity system.

I have so much conflicting information, and can't sort it out. Here's the general story: 1) GC provided Mini split proposal (in link below) 2) "Sila" provided HV proposal (in link below) 3) We had an independent construction consultant review and provided comments (thread PDF in link below)

To me, it seems that the MS did a calculation based on Sqft, but HV did one based on load. The consultant thinks that 1 zone is not good (as you can read), but the HV company is insisting that's just how the systems work and proper installation ensures proper airflow.

I know it's a lot to ask, but I would greatly appreciate an expert's take on this - I need to make a decision and don't know what is sales and what is fact.

All the info in the two proposals as well as the consultants comments and responses can be found in this dropbox link.

Thank you so much!!!!

https://www.dropbox.com/sh/halqe0swe0hnqf4/AAC8YveQDaqI0Z7XYVPvoq5ma?dl=0

submitted by /u/atess91
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