Heat pump vs furnace calculator
Most calculators ask you to type in your energy prices. This one looks them up from your ZIP code, using the latest figures the US Energy Information Administration publishes for your state.
How this is worked out
Your heating need is estimated from floor area and your state's heating degree days, then converted to running cost at your local prices — gas through your furnace's AFUE rating, electricity through the heat pump's HSPF2. Payback compares the roughly $3,200 extra a heat pump costs to install over an equivalent furnace, not its full price, because someone replacing a dying furnace is choosing between two purchases rather than one.
It is an estimate. Insulation, air sealing, ductwork and how you actually use your thermostat all move the answer, and no calculator can see those. Treat it as a way to sanity-check a contractor's quote, not as a substitute for one.