Best heating/cooling & water solution for 7-unit multifamily?
Hi, I'm in the midst of renovating a ~5500 sq ft commercial building and converting it to a ~6000 sq ft multi-family residential. It'll have 6 resi rental units + 1 ground-level commercial space. The building currently has natural gas and uses radiator heating, there is no central cooling system. We currently have a small central boiler that provides hot water, but it's undersized once we add 8 showers, 7 dishwashers, 2 common W/D, 2 in-unit W/D, etc.
My question is what's the best strategy for adding heating/cooling to each unit? And what's the best way to improve the provision of hot water?
Our current plan is to install VTACs for heating/cooling, or vertical terminal air conditioners, in each unit (GE Zonline, see here http://www.geappliances.com/ge/zoneline.htm), sub-metered to each tenant's electric meter. Does anyone have experience with VTACs for residential rentals? Pros and cons? Is there a better way to do heating/cooling?
In terms of hot water, we were planning to install a Commercial High Efficiency Gas Water Heater in the basement (Rheem's SPIDERfire Water Heater, see here https://www.grainger.com/product/6FGU6), and use it to serve all 7 units. What do people think of this?
Thanks for your time & help