Sort of depends on the structure and heat load of the building. Around here it's hot and warehouses generally get rooftop units (RTUs) which are packaged (all in one) units. These you may have seen at Home Depot which they use in the ceiling.
Depending on the state/country you live in, there are probably regulations selling equipment with R-22 and R-410A refrigerant. Here in Texas an unlicensed person can purchase a package unit, but not a split unit that needs to be assembled and charged. So you might be able to get a packaged unit for side of building installation or RTU online or direct, then pay a local contractor to set it up for you. If it's a big warehouse there will probably be additional cost in them needing to bring a crane or cherry picker lift to the site. A quick browse online is showing 10 ton RTUs starting at about $5,000.
I'm actually in Dallas. Yeah I need a packaged unit, our previous was 208-230 refrigerant, 3 phase, 10 ton. That's all I know; somehow all the information regarding the actual units were ripped off.
I know little other than I pretty much hate HVAC contractors here. Seems like they're all out to rip you off, more so than plumbers/electricians/doctors. And no one wants to actually repair a unit any more; they all want to sell you a new one.
here is an inside tip, call 6 contractors and have them all look at the job at the same time....it will be great!! you were planning on using a contractor right? unless you and brother-in -law are going to do it?
As a long time veteran of the HVAC business(mostly on the sales side for 2 of the top 5 manufacturers in the US) this business can be really confusing-I would agree that you should use a contractor- (the 208/230 3phase is electrical designation btw-nothing to do with your refrigerant)
Odds are about 90% that the refrigerant is R22-is the unit on the roof already or is it sitting on the ground with the duct work going through the side of the building?
Wholesale cost of a unit to the contractor for this unit will be around 4-5k depending on the manufacturer and the contractor(bigger contractors buy more units and get better pricing-but usually have higher overhead also)-depending on what needs to be done on the site you will spend as little as 1k on install or as much as 5k or more if the unit is on the roof and items like new transition roof mounts(called roof curbs in the industry) and cranes etcetera.
It is difficult to buy a unit this large without a contractor.
Oh-and cheapest and most efficient and mutually exclusive terms when buying HVAC equipment
