Heat pump vs. gas furnace in Phoenix, AZ
In Phoenix, a heat pump is the cheaper choice, and not by a little. $1,000 is what Phoenix would pay extra to go electric rather than replace the furnace and AC with the same again, once the $2,000 federal credit is applied. That premium is recovered through $384 of lower running costs every year, landing the payback clock at roughly 2.6 years. That verdict holds specifically for Phoenix's own climate and rates, not a national average.
How cold Phoenix actually gets
1212 heating degree days pile up here every year, so Phoenix barely has a winter to speak of; the cooling side runs to 4406 cooling degree days, where summers are severe enough that cooling can dominate the annual bill. The 99% winter design temperature here — the cold snap equipment must be sized for, not the seasonal average — is 30°F, against a record low of 30°F. That puts the seasonal coefficient of performance at 3.09 for the recommended standard unit. Phoenix's winters don't get cold enough to need the cold-climate premium — a standard unit holds up fine. Source: NOAA station PHOENIX DEER VALLEY ARPT, 8 miles from Phoenix — the closest one on record.
Phoenix's running-cost comparison, in dollars
Electricity use for heating alone comes out to about 993 kWh a year on the 2000-square-foot reference house; folding in cooling puts the electric bill near $739 a year. Phoenix's gas rate of 18.58 per Mcf, applied to the 13 Mcf a year the furnace burns, puts its running cost near $1,122 a year, against 15.55¢ per kWh for electricity. Looked at as a full purchase rather than an incremental one, payback here is roughly 28.7 years, leaving the 15-year total $4,758 ahead.
The other scenario: no gas furnace to begin with
Not every home in Phoenix has gas service. Swap the comparison to resistance heat instead of gas, and Phoenix's answer improves. About $627 a year comes back this way, enough that the 8.8-year payback clears the $5,500 premium comfortably within the equipment's life.
Phoenix against the rest of the country
Phoenix lands at position 2796 out of 3206 cities on heating severity (coldest is 1), and 5 out of 3206 by population size (biggest is 1). That's the mildest third of cities covered, where utility rates carry more of the answer than climate does.
Next step for 1,673,164 people in Phoenix
Phoenix, Arizona is home to about 1,673,164 people, and the figures above are the same ones a local HVAC contractor uses to size and quote a system — this site doesn't guess where a real quote would land, it just tells you whether it's worth asking for one. Given the math above, Phoenix is a place worth lining up quotes ahead of a breakdown, not waiting for one.
Get quotes from local HVAC contractors before deciding.
More on how this number was built
Nothing above is a black box: the methodology guide shows the full arithmetic behind Phoenix's 3.09 seasonal COP and payback figure. The $2,000 federal credit baked into Phoenix's number is explained, with the before-and-after math, in the tax credit guide.