4-zone mini-split: the short answer
As configured, budget roughly $8,400 – $15,500 for a 4-zone mini-split, rising toward $10,900 – $23,000 once new ductwork and electrical work are included. Four zones put a ductless system at the top of its typical range, and at that size the installed total often overlaps what a central ducted system would cost. You are paying for a larger outdoor unit and four separate head installations — but none of the budget goes to ducts. The biggest swing is still your own site, so itemize your estimate above.