Many homeowners do not choose to have central air conditioning for practical and understandable reasons. Attic space in low or flat-roofed homes prevents the installation of ductwork. Retrofitting older structures to permit it requires a significant investment in money, time and disruption to home life. A new bedroom or workroom may give you space to expand, but it becomes a significant project to heat and cool it with a central HVAC system. As affordable and efficient alternatives, mini or multi ductless units offer many options worth considering.