[jpd25]

Original author here. Those figures are from a local study done last year by the Laminar Collective (linked to in the piece). They do not account for state or federal rebates/incentives. They're included to demonstrate the wide range of installation costs, which can feel arbitrary to a homeowner and undermine their confidence, thus making it less likely that they will choose to install a heat pump.

Comparing the cost of a heat pump to window AC units is missing the point since, as you're well aware, a heat pump provides both cooling and heating. A homeowner who is considering a heat pump is almost certainly replacing a gas furnace and/or a central AC system. When you factor in the cost of replacing two systems with one, plus higher effiency gains/lower operating costs, and money back on rebates, heat pumps can be cost competitive.

Massachusetts (where this study was done) is still offering generous incentives as well as 0% financing through the Mass Save program.