I have an existing 2-story home that was built without an attic and without A/C. I need to get A/C installed. The only vents are downstairs for the heater, locatedin the basement. How well will A/C work with floor vents (return air low on a wall)? Also, for the two bedrooms upstairs, do you recommend a Ductless Split system? If so, is it better to have two entire systems for each bedroom, or one dual system?

I do not want window units or portable units.

Thank You!