Don't just take into account the SIZE of the room but also look at what needs to be cooled. In a large open office, are there a couple employees that need to be comfortable of is it a room full or workstations and cubicles? You might be able to strategically position a few spot coolers in the commercial space for comfort cooling the employees rather than cooling the entire area.
Don't forget to include all the heat-generating equipment needed to cool a server room if there is one in the space. A 10 x 10 room with one server will require much less cooling than the same room with 20 servers.
Be sure to check out the available power in the space that needs cooling. Do you have dedicated 120VAC outlets? Any 208/230/1 power you can pull from a panel? Whether you own portable air conditioners or need to rent spot coolers, the power you have readily available will determine which units you can use to cool the space.
To effectively cool the space, you will need to duct the warm condenser air out of the space you are cooling. This doesn't mean you will need to duct the air outside the building but you will need to check and see if you have plenum return above the ceiling. You may even be able to temporarily duct the air to an adjacent room or unused area. Bottom line -- if you don't get rid of the warm air from the condenser, it will eventually get warmer in the space.
All air conditioners will produce condensate. All spot coolers will have some type of condensate reservoir or condensate tanks. You can manually empty the condensate container. Some portable air conditioners have optional condensate pumps to automatically pump the condensate to a drain line. The COOLIT Portable Air Conditioners have BOTH condensate tanks AND a condensate pump -- you choose the condensate removal method that works best for your application. The super sweet part is that the pump is already in the unit so you won't have to install it to replace the tanks.
Next time you need portable air conditioners -- and you know you will sooner or later -- you'll be ready to go!