Hello. I need some advice in adding a cental A/C system to a ductless house. The house is a duplex. I want to add a seperate system to the first and second floor. The second floor has an attic above and the first floor has a crawl space. The heating is electric and is really only used in the summer so heating is not a issue. It currently uses room ac which I want to do a way with. What systems would you recommend? Thanks.