Central ducted heat pump (4-ton): the short answer
As configured, budget roughly $12,500 – $22,500 for a central ducted heat pump (4-ton), rising toward $14,500 – $27,500 once new ductwork and electrical work are included. Four tons is near the top of common residential sizes, and per-ton pricing means equipment and install cost scale with it. A system this large also raises the odds of extras — ducts sized for a smaller unit may need reworking to move enough air, and the bigger circuit makes panel work more likely. The biggest swing is still your own site, so itemize your estimate above.