2/3rds of that cost is labor. 3 ton multi-zone heatpump kit is $2500-3500, another $250-500 for an electrician to pull #6s and a ground to a 60A disconnect outside and sealtite whip into the heatpump, and 60-80 hrs at $125/hr to install the heat pump and air handlers, including all the exterior wall penetrations and sealing, running glycol lines, installing thermostats, wiring air handlers, etc.